1

Paulo Fernando Ribeiro, PhD, IEEE FellowCo-Chairman of the Power Quality Steering Committee of the IEEE

Professor: Calvin College

Visiting Scholar: Center for Advanced Power Systems (FSU)

Tópicos Avançados em Qualidade de Energia Elétrica

5 0 5

0

10 5 0 5 102

0

2

5 0 5

0

AgradecimentosMark McGranaghan

Alex McEachernAlex EmanuelErich Gunther

Gerald HeydtONS, EPRI August, 2005

A Power System of the Future?

Hospital with cogeneration (1.5 MW)

SubstationFeeder

Residential photovoltaic system

(6 kW)

Utility-owned Photovoltaic site

(500 kW)

Small wind turbine (10 kW)

Factory with natural gas fuel cell (100 kW to 5 MW)

Residential Fuel cell (7 kW)

Utility-owned wind turbine site (1 MW)

With permission of M. McGranaghan, and T. Key

2

E x a m p l e W a v e s h a p eo r R M S v a r i a t i o n

P o w e r Q u a l i t yV a r i a t i o nC a t e g o r y

M e t h o d o fC h a r a c t e r i z i n g T y p i c a l C a u s e s

E x a m p l eP o w e rC o n d i t i o n i n gS o l u t i o n s

Impulse

10 15 20 25 30- 150

- 100

- 5 0

0

50

10 0

15 0

Tim e (m S )

I m p u l s i v eT r a n s i e n t s

P e a k m a g n i t u d e ,R i s e t i m e ,D u r a t i o n

L i g h t n i n g ,E l e c t r o - S t a t i cD i s c h a r g e ,L o a d S w i t c h i n g ,C a p a c i t o rS w i t c h i n g

S u r g e A r r e s t eF i l t e r s ,I s o l a t i o nT r a n s f o r m e r s

Oscillatory Transient

0 20 40 60 80- 20 0

- 15 0

- 10 0

- 50

0

50

10 0

15 0

Tim e (m S )

O s c i l l a t o r yT r a n s i e n t s

W a v e f o r m s ,P e a k M a g n i t u d e ,F r e q u e n c yC o m p o n e n t s

L i n e / C a b l eS w i t c h i n g ,C a p a c i t o rS w i t c h i n g ,L o a d S w i t c h i n g

S u r g e A r r e s t eF i l t e r s ,I s o l a t i o nT r a n s f o r m e r s

Voltage Sag

0 100 200 300 400 500 - 10

10

30

50

70

90

1 10

Tim e (m S )

S a g s / S w e l l s R M S v s . t i m e ,M a g n i t u d e ,D u r a t i o n

R e m o t e S y s t e mF a u l t s

F e r r o r e s o n a n tT r a n s f o r m e r s ,E n e r g y S t o r a gT e c h n o l o g i e s *U P S

Interruption

0 20 00 40 00 60 00 0

20

40

60

80

10 0

12 0

Tim e (m S)

I n t e r r u p t i o n s D u r a t i o n S y s t e mP r o t e c t i o n( B r e a k e r s ,F u s e s ) ,M a i n t e n a n c e

E n e r g y S t o r a gT e c h n o l o g i e s *U P S ,B a c k u pG e n e r a t o r s

RMS Overvoltage

0 1 00 0 2 00 0 3 00 0 4 00 0 5 0

6 0

7 0

8 0

9 0

1 00

1 10

1 20

Tim e (m S )

U n d e r v o l t a g e s /O v e r v o l t a g e s

R M S v s . T i m e ,S t a t i s t i c s

M o t o r S t a r t i n g ,L o a d V a r i a t i o n s ,L o a d D r o p p i n g

V o l t a g eR e g u l a t o r s ,F e r r o r e s o n a n tT r a n s f o r m e r s

Distorted Current Waveform

10 20 30 40 50 60- 100 0

- 5 00

0

500

10 00

Tim e (m S )

H a r m o n i cD i s t o r t i o n

H a r m o n i cS p e c t r u m ,T o t a l H a r m .D i s t o r t i o n ,S t a t i s t i c s

N o n l i n e a r L o a d s ,S y s t e mR e s o n a n c e

F i l t e r s ( a c t i v e p a s s i v e ) ,T r a n s f o r m e r s( c a n c e l l a t i o n oz e r o s e q u e n c ec o m p o n e n t s )

Voltage Flicker

0 25 50 75 100 125 90

95

100

105

110

Tim e (s)

V o l t a g e F l i c k e r V a r i a t i o nM a g n i t u d e ,F r e q u e n c y o fO c c u r r e n c e ,M o d u l a t i o nF r e q u e n c y

I n t e r m i t t e n tL o a d s ,M o t o r S t a r t i n g ,A r c F u r n a c e s

S t a t i c V a rS y s t e m s

Peak overvoltage(pu)

XXXTransients

SARFI70(2)

XXXVoltage Sags

THD < 3.0%CP95%

XXXHarmonics

V2/V1 < 2.0%CP95%

XXXUnbalance

PstD95%< 1.0PltS95% < 0.8

XXXFlicker

–1Hz <fc < +1HzCP99.9%

XXXXXXFrequency Variation

-5% <Vn< +5%(1)

XXXVoltage Regulation

DEC, FECXXXContinuity

Indices and compatibility levels

DisturbancePhenomena

SteadyState

Phenomena

3

IndustryAssessments

Performance Indices

System Monitoring(Permanent or

Surveys)

System Studies(Simulations)

Actual Performance

Compare withIndices

IdentifyResponsibility and

Solutions

Implement Solutionsand Assess

Performance

Periodic ReportingEducation and

InformationPrograms

ExpectedPerformance

Information , Regulation,and Industry Interaction

Analysis and SimulationTools and Procedures

Monitoring and PerformanAssessment Systems

Qualidade de EnergiaUma Visão Integrada

QUESTIONS

What is power quality and its context?

What is the cost of power quality and related responsibilities?

What is the value of power quality for the different players?

Are the definitions and standards appropriate?

How deviations should be treated (rigid or flexible approach)?

What is the impact of deregulation and DG developments on PQ?

How is the power sector addressing power quality needs and risks?

How well equipped is the sector for dealing with an increasingly complex environment?

What are topics for future research and development (real needs)?

4

The Current Revolution is a Consequence of the Convergence of:

Power Systems Classical OperationAdvanced Power Systems Management

New Generation and Distribution TopologiesNew Power Electronics Technologies

Advanced Signal Processing and AnalysisAdvanced Monitoring

Much Higher Computer PowerAdvanced / Intelligent Communications, and Computer

Controls

Vision"Where there is no vision, the people perish"

Proverbs 29:18

Philosophy / StrategyNo aspect of reality (or a system) should be viewed in isolation

Initiative

Imagination, Creativity, Sustainability Norms and Citizenship (Ethics / Morality – engineering/technology is not a morally neutral activity)

Philosophy / Strategy?

5

Generation

Transmission

Performance Parameters

Planning

Operation

Economic Feasibility

Distribution

The Big, Integrated, Macro Picture

ConsumersConsumers

Accessibility

Security

Continuity

Reliability

Voltage (Power) Quality

Performance Parameters

The Big, Integrated, Macro Picture

6

The Big, Integrated, Macro Picture

Concepts and Issues

Techniques (software)Systems and ConceptsHardwareMeasuring and MonitoringComputer Modeling and SimulationDeregulation and Distributed GenerationStandardsManagement

Caution

Advanced Concepts

Techniques (software)

Wavelet Theory

Expert Systems

Fuzzy Logic

Genetic Algorithms

Neural Network

Real Time Digital Simulation

Chaos Theory

Multi-Agents

7

Advanced Concepts

Systems and Concepts

PQ Parks

Custom Power / FACTS / Transfer Switches

Higher Immunity

Special Contracts

Power Management Companies

Macro-Economic Analysis

Advanced Concepts

Hardware

Active Harmonic Filters

Micro SMES for Power Quality

Large SMES for Transmission / Distribution

PWM Based Higher Power Compensators

FACTS Controller, Custom Power Devices

Transfer Switches

8

Advanced Concepts

Measuring and Monitoring

Artificial Intelligence Instruments

Remote Access (Internet)

Integrated Diagnostic

Comprehensive System Monitoring

Centralized Monitoring (GPS)

Advanced Concepts

Computer Modeling and Simulation

Graphical Environment

Inclusion of Artificial Intelligence (fuzzy / neural, wavelets)

Integrated Economic Analysis

Real Time Digital Simulation(Hardware-in-the-Loop)

9

Advanced Concepts

Deregulation and Distributed Generation

Impact of Deregulation and DG on PQ

Impact of PQ on Deregulation and DG

Advanced Concepts

Standards

Flexibility

Compatibility

Commonality (IEEE / IEC)

Increased Immunity

10

Advanced Concepts

Management

Integrated PQ

Integrated Self-Healing Network and Communication Systems

Integrated Consumers, Agents Communication Interface

Integrated / Comprehensive PQ Database

Advanced Concepts

Caution

Useless research

Unnecessary technical sophistication

Pet subjects

Be aware of the increasing complexity of the system

Keep an integrated (global) perspective

11

VSI CSI

Natural Forced

Synchronous PWM

Hard Soft

Two-Level Multi-Level

SCR GTO IGBT MCT MTO

System

CommutationApproach

SwitchingTechnology

TransitionApproach

CircuitTopology

DeviceType

Power Electronics - Semiconductor DevicesDecision-Making Matrix

Example of aA Multifaceted Decision Process

An Integrated Perspective is necessary

Example

General Guidelines

General Philosophy: Main Function

Within each power quality category, the PQ Program defines the following aspects.

Philosophy

•Problem Definition – Why is it important to ----?

•Responsibilities – What needs to be done? By whom? (individual, global limits to be respected by ONS / Agents)

•Flexibility to allow for different system characteristics

Management

•Data Collection (Format, etc.)

•Duration, Management, etc.

•Tracking system performance

•Where, When, How?

12

General Guidelines

General Philosophy: Main Function

Within each power quality category, the PQ Program defines the following aspects.

Technical•Indices (definitions)

•Monitoring (functional Specs, etc)

•Standards

What is Power / Voltage Disturbance / Quality?

Definitions

“Any power problem manifested in voltage, current, or frequency deviations that results in the failure or misoperation of customer equipment."

IEEE PES Working GroupP1433 Power Quality Definitions

Of all power quality problems, approximately 60% are internally generated within the home or business. Twenty percent(20%) are the result of neighboring customers.Fifteen percent(15%) arethe result of natural phenomenon such as lightning, tree limbs, and animal contacts. And five(5%) are normal utility operations such as the operation of a circuit breaker.

13

Power Disturbance

Any deviation from the nominal value (or from some selected thresholds based on load tolerance) of the input ac power characteristics.

When monitoring electric power, with many devices, thresholds are established to define what constitutes a power disturbance. Often, these thresholds are determined by the type of problem that is occurring. For example, if a certain piece of equipment is failing, device specific thresholds will be used (i.e. voltage limitations and noise limitations from the manufacturer) to establish the definition of a power disturbance.

What is Power / Voltage Disturbance / Quality?

Definitions

“Any power problem manifested in voltage, current, or frequency deviations that results in the failure or misoperation of customer equipment."

Power Quality

The concept of powering and grounding sensitive equipment in a manner that is suitable to the operation of that equipment.

NOTE—Within the industry, alternate definitions or interpretations of power quality have been used, reflecting different points of view. Therefore, this definition might not be exclusive, pending development of a broader consensus.

What is Power / Voltage Disturbance / Quality?

Definitions

“Any power problem manifested in voltage, current, or frequency deviations that results in the failure or misoperation of customer equipment."

14

Power Quality

A point of view of an equipment designer or manufacturer might be that power quality is a perfect sinusoidal wave, with no variations in the voltage, and no noise present on the grounding system. A point of view of an electrical utility engineer might be that power quality is simply voltage availability or outage minutes.

Finally, a point of view of an end-user, is that power quality or “quality power”is simply the power that works for whatever equipment the end-user is applying. While each hypothetical point of view has a clear difference, it is clear that none is properly focused.

What is Power / Voltage Disturbance / Quality?

Definitions

“Any power problem manifested in voltage, current, or frequency deviations that results in the failure or misoperation of customer equipment."

Power Quality

An environment where the equipment designer or manufacturer clearly states the equipment needs, and the electrical utility engineer indicates the system delivery characteristics, and the end-user then predicts and understands the equipment operational disturbances that will likely be encountered on a yearly basis is a better scenario. This allows a cost justification to be performed by the end-user to either improve equipment operation by installing additional components or improve the electrical supply system through installation of additional, or alteration of existing components.

What is Power / Voltage Disturbance / Quality?

Definitions

“Any power problem manifested in voltage, current, or frequency deviations that results in the failure or misoperation of customer equipment."

15

What is Power / Voltage Quality?Definitions

IEEE Power Quality StandardsIEEE SCC-22: Power Quality Standards Coordinating Committee

IEEE 1159:Monitoring Electric Power Quality

IEEE 1159.1: Guide For Recorder and Data Acquisition Requirements

IEEE 1159.2: Power Quality Event Characterization

IEEE 1159.3: Data File Format for Power Quality Data Interchange

IEEE P1564:Voltage Sag Indices

IEEE 1346:Power System Compatibility with Process Equipment

IEEE P1100: Power and Grounding Electronic Equipment (Emerald Book)

IEEE 1433: Power Quality Definitions

IEEE P1453: Voltage flicker

IEEE 519: Harmonic Control in Electrical Power Systems

Padrões De Qualidade de Energia

Perspective GlobalDefinições, Índices, Medições, Comprovações, etc.Filosofia: Níveis de Compatibilidade (sistema / equipamento, fontes de desvios)Implementação Prática

16

Os Padrões de Qualidade existem num contexto global e, são sujeitos a função objetivo dos sistemas de suprimento elétrico, o qual é providenciar suprimento adequado, tecnicamente compatível, confiável, e econômico da energia elétrica.

Uma Perspective Global

Padrões de Qualidade de Energia

© 2004 Power Standards Lab. All rights reserved.

Electricity Price - World-wide

Source: © 2004 EPRI

Uma Perspective Global – Preço

17

© 2004 Power Standards Lab. All rights reserved.

Major Power Outages Around the World

Source: © 2004 EPRI

Uma Perspective Global - Apagões

© 2004 Power Standards Lab. All rights reserved.

Distribution Reliability Index – SAIFI

Source: © 2004 EPRI

Uma Perspective Global - Confiabilidade

18

PSL

© 2004 Power Standards Lab. All rights reserved.

Distribution Reliability Index – SAIDI

Source: Mark Lauby, EPRI, Fukuoka. © 2004 EPRI

Uma Perspective Global - Confiabilidade

© 2004 Power Standards Lab. All rights reserved.

Voltage sags can have the same effect as outages for industrial customers.

Source: Mark Lauby, EPRI, Fukuoka. © 2004 EPRI

SARFI70

Uma Perspective Global - Impacto

19

Teorias e Princípios de Ética e Padrões Sociais

Aplicados a Utilização de Padrões de Qualidade

Lei Natural – Consistente com a funcionalidadeUtilitarianismo – Maior valor para a comunidadeFormalismo – Independente de Interesses

Autonomia - Liberdade de EscolhaNão – maleficência – Evitar problemasBeneficência – Promover melhoramentoJustiça – Retribuir infratores

Virtude – Ação responsável em situações difíceis e complexas

Heresias Morais

Aplicados a Utilização de Padrões de Qualidade

Subjetivismo – Muito complexo ...Emotivismo – Deve ser a culpa dele ...Positivismo – Tudo vai dar certo no fim ...Pragmatismo – Com tanto que funcione...Otimismo - Nada vai acontecer ...Relativismo - Não se pode dizer nada ...Ceticismo – Essas medições não valem...Egoísmo – É o problema dele ...

Virtude – Ação responsável em situações difíceis e complexas

20

Mas o Porquê de Padrões?

•Estabelece Expectativas

• Melhora a Compatibilidade Entre Sistemas

• Permite Melhor Comunicação Entre Engenheiros de Potencia e Engenheiros de Equipamento

O Porquê de Problemas Com Padrões

• Escrito por seres humanos. Erros

• Aplicados por seres humanos. Erros.

•Exemplo: IEEE 519 aplicado a terminais de equipamento

• Desencorajam inovações .

• Normas contem suposições não claramente definidas.

• Normas podem tornar-se peso para alguns.

• Normas tolhem / impedem inovações.

21

Compatibility level

Assessed level

Disturbance magnitude

time

Equipment immunity test levels

Utility planning levels

Perspectivas: Social, Ética, Etc.

IEC, IEEE, CIGREXIndustria

Uma Perspective GlobalEstabelecendo Padrões

Generation

Transmission

PQ Performance Parameters

Planning

Operation

Economic Feasibility

DistributionConsumersConsumers

22

Accessibility

Security

Continuity

Reliability

Voltage (Power) Quality

Performance Parameters

The Big, Integrated, Macro Picture

Uma Perspective GlobalEstabelecendo Padrões

Compatibility Levels

Customer System Impact Limits

System Performance Expectations

Measurement and Assessment

Methods

Customer System and Equipment

Immunity Requirements

Equipment PQ Limits

System Solutions and their implementation

Customer and equipment solutions

to limit impact on system

Customer and equipment solutions

for immunity improvement

23

Desenvolvimentos de Padrões

International Standards Groups – IEC (mostly SC 77A)– CENELEC – CIGRE (AG 4.1) UIE, UNIPEDE, CIRED.....

Standards Groups in North America– IEEE (mostly PES & IAS)– ANSI, CSA

– UL, NEMA, NEC, NIST.....

IEC Power Quality Standards

Numbering61000-1-X - Definitions and methodology 61000-2-X - Environment (e.g. 61000-2-4 is compatibility levels in industrial plants) 61000-3-X - Limits (e.g. 61000-3-4 is limits on harmonics emissions) 61000-4-X - Tests and measurements (e.g. 61000-4-30 is power quality measurements) 61000-5-X - Installation and mitigation 61000-6-X - Generic immunity & emissions standards

IEC SC77A: Low frequency EMC Phenomena -- essentially equivalent of "power quality" in American terminology

TC 77/WG 1: Terminology (part of the parent Technical Committee)SC 77A/WG 1: Harmonics and other low-frequency disturbances SC 77A/WG 6: Low frequency immunity tests SC 77A/WG 2: Voltage fluctuations and other low-frequency disturbances SC 77A/WG 8: Electromagnetic interference related to the network frequency SC 77A/WG 9: Power Quality measurement methods SC 77A/PT 61000-3-1: Electromagnetic Compatibility (EMC) - Part 3-1: Limits -Overview of emission standards and guides. Technical Report

24

IEEE Power Quality StandardsIEEE SCC-22: Power Quality Standards Coordinating Committee IEEE 1159:Monitoring Electric Power Quality

IEEE 1159.1: Guide For Recorder and Data Acquisition Requirements IEEE 1159.2: Power Quality Event Characterization IEEE 1159.3: Data File Format for Power Quality Data Interchange

IEEE P1564:Voltage Sag Indices IEEE 1346:Power System Compatibility with Process Equipment IEEE P1100: Power and Grounding Electronic Equipment (Emerald Book) IEEE 1433: Power Quality Definitions IEEE P1453: Voltage flicker IEEE 519: Harmonic Control in Electrical Power Systems IEEE Harmonics Working Group

Single-phase Harmonics Task Force IEEE P519A Guide for Applying Harmonic Limits on Power Systems Interharmonics Task Force Harmonics Modeling and Simulation Task Force Probabilistic Aspects of Harmonics Task Force

Surge Protective Devices CommitteeSeventeen sub-committee links can be found at the "Sub-committee pages" link... IEEE P446: Emergency and standby power IEEE P1409: Distribution Custom Power IEEE P1547: Distributed Resources and Electric Power Systems Interconnection

Other Power Quality Standards

UIE: International Union for Electricity Applications

CENELEC: European Committee for Electrotechnical Standardization

UNIPEDE: International Union of Producers and Distributors of Electrical Energy

ANSI: American National Standards Institute

ANSI C62: Guides and standards on surge protection

ANSI C84.1: Voltage ratings for equipment and power systems

ANSI C57.110: Transformer derating for supplying non-linear loads

CIGRE: International Council on Large Electric Systems

CIRED: International Conference on Electricity Distribution

CBEMA / ITIC curve

25

Two Basic Types of PQ Variations

Steady State PQ– Voltage regulation– Unbalance– Frequency– Harmonics– Flicker

Disturbances– Outages and interruptions– Voltage sags (rms variations)– Transients

IEC – Estrutura Geral

Part 1: General (IEC Pub 61000-1)– fundamental principles, definitions, terminology

Part 2: Environment (IEC Pub 61000-2)– description, classification and compatibility levels

Part 3: Limits (IEC Limits 61000-3)– emission and immunity limits, generic standards

Part 4: Testing and measurement (IEC Pub 61000-4)– techniques for conducting

Part 5: Installation and mitigation (IEC Guide 61000-5)– installation guidelines, mitigation methods and devices

26

Working Group 1 – Harmonics and other Low frequency Disturbances. Focus on limits and methods of measurement for harmonics and interharmonics.

Working Group 2 – Voltage Fluctuations (flicker) and other Low Frequency Disturbances. Develops limits for voltage fluctuations caused by end user equipment and methods of measurement as appropriate. This working group will be working on an update to the document on reference impedances that can be used for evaluatingthe impact of equipment on the system.

Working Group 6 – Low Frequency Immunity Tests. Develops testing procedures for evaluating equipment immunity from power quality variations.

Working Group 8 – Electromagnetic Interference Related to the Network Frequency. This group is addressing the full range of power quality phenomena on the network and the interaction issues with consumers.

Working Group 9 – Power Quality Measurement Methods. Currently developing IEC 61000-4-30, an overall guide defining the requirements for power quality monitoring equipment.

IEC – Atividades

CIGRE Study Committee C4 Input Para Normas

JWG C4.1.01 Power Quality General Aspects E. Gunther (US) 1977 2006 TF C4.1.02 Voltage Dip Prediction Tools J.M. Vlasco (SP) 2003 2005 JWG C4.1.03 Emission Limits for Disturbing Loads G. Beaulieu (CA) 2003 2006 JWG C4.1.04 Power Quality Indices and Objectives G. Beaulieu (CA) 2000 2004 JWG C4.1.05 Technical Performance Benchmarking Guidelines M. McGranaghan (US) 2005 2008 JWG C4.1.06 PQ Instrument Test Protocols E. Gunther (US) 2005 2007 JWG C4.1.07 Economic Framework for Voltage Quality JL Gutierrez Iglesias (ES) 2005 2008 TF C4.1.08 Review Of Flicker Objectives - HV,MV&LV Systems A. Detmar (DE) 2005 2007 TF C4.1.09 Emission Assessment Techniques E de Jaeger (BE) 2005 2007 WG C4.1.10 Dip Immunity of Equipment - Customer Installations To be appointed 2005/6 2008 ActiveCompletedScope & proposed convener reviewed and approved by Study Committee C4Scope under preparation

27

Recentes Desenvolvimentos

CIGRE C4.07 (C4.1.04) – Recommended Indices and Benchmarking Results for PQ and ReliabilityIEC 61000-4-30 provides specifications for pq monitoring and provides the basis for IEEE coordinationIEC 61000-4-15 provides flickermeter specifications. It was amended to include 120 volt and 100 volt lamps and has been adopted by IEEE 1453.IEC 61000-3-2 provides harmonic limits for equipment. This approach has not been adopted in North America.IEC 61000-3-6 and 61000-3-7 provide guidelines for harmonic and flicker emissions from customer facilities. They are undergoing revision in parallel to a revision of IEEE 519.

Some important recent developments

CIGRE C4.07 (C4.1.04) – Recommended Indices and Benchmarking Results for PQ and ReliabilityIEC 61000-4-30 provides specifications for pqmonitoring and provides the basis for IEEE coordinationIEC 61000-4-15 provides flickermeter specifications. It was amended to include 120 volt and 100 volt lamps and has been adopted by IEEE 1453.IEC 61000-3-2 provides harmonic limits for equipment. This approach has not been adopted in North America.IEC 61000-3-6 and 61000-3-7 provide guidelines for harmonic and flicker emissions from customer facilities. They are undergoing revision in parallel to a revision of IEEE 519.

28

IEEE Standards Coordinating

1159 – Measurements1453 – Flicker519 – Harmonics1564 – Voltage Sags…

Voltage sags and interruptions –What is needed?

Common method of measurement and assessment (indices)Benchmark performance as a function of system characteristicsStatistical methods of characterizing performance (1564)Application guidelines for performance improvement options (e.g. IEEE 1409)Equipment performance standards (e.g.IEC 61000-4-11, 4-34)Economic evaluation with a system perspective

29

Possible Problems

Caution SevereDistortions

DangerousLevels

NormalLevels

A B C D E F G RTL0

1

Norm

alB

elowN

ormal

Over

Heating

Very

Hot

Below

Norm

alab

cd

e

Equi

pmen

t Ma l

fun c

tion

Mag

nitu

de $

Pha

se

An g

le

Individual Harmonics (Vh)Equipment Malfunction

Fuzzy - Color Code Criteria

No Problem

Caution

Possible Problems

Imminent Problems

Normas Flexíveis e Criativas

( ) ( ) ( )( ) ⎟⎟

⎠

⎞⎜⎜⎝

⎛ −=

kUrefkUrefkUkRTL ,0max

Relative Trespass Level (RTL)

Uk - measured or calculated harmonic voltage

Uref - harmonic voltage limit (standard or particular equipment)

k - harmonic order

2 4 6 8 10 12 140

2

4

6

88

0

RTL k

132 k

0 0.05 0.10

2

4

6

88

0

RTL k

.10 Uk

30

( )∑=

=50

2

22

kkRTLHDD

Harmonic Distortion Diagnostic Index

Exponent = 2 or 4 ?k = 50 or less ?

Total Harmonic Distortion Diagnostic Index

⎟⎠⎞

⎜⎝⎛ −

=Vthd

VthdVTHDTHDD ,0max

VTHD - total harmonic distortion measure or calculated

Vthd - total harmonic distortion limit

31

2 4 6 8 10 12 140

0.02

0.040.03

1103−×

Uk

Urefk

132 k

Uk

0.0010.0150.0010.030.0010.0150.0010.0090.0010.020.0010.015

:= Urefk

0.010.010.010.010.010.010.010.010.010.010.010.01

:=

RTL

2

2

34

56

78

9

1011

1213

0

0.50

20

0.50

0

01

00.5

=

T

Example 1

VHDD2

13

k

RTLk( )2∑=

:=

VHDD 2.398=

VTHD2

13

k

Uk( )2∑=

⎡⎢⎢⎣

⎤⎥⎥⎦

100⋅:=

VTHD 4.541=

THDD max 0VTHD Vthd−( )

Vthd,⎡⎢

⎣⎤⎥⎦

:=

THDD 0=

Example 1

Vthd=5%

32

Example 2

2 4 6 8 10 12 140

0.01

0.02

0

Uk

Urefk

132 k

Uk

0.0010.010.0010.0

0.0010.010.0010.010.0010.010.0010.01

:= Urefk

0.010.010.010.010.010.010.010.010.010.010.010.01

:=

RTL

223

456

789

101112

13

00

000

000

000

0

=

VHDD2

13

k

RTLk( )2∑=

:=

VHDD 0=

VTHD2

13

k

Uk( )2∑=

⎡⎢⎢⎣

⎤⎥⎥⎦

100⋅:=

VTHD 2.249=

THDD max 0VTHD Vthd−( )

Vthd,⎡⎢

⎣⎤⎥⎦

:=

THDD 0=

Example 2

Vthd=5%

33

Example 3

2 4 6 8 10 12 140

0.02

0.040.05

1 10 3−×

Uk

Urefk

132 k

Uk

0.0010.0010.0010.020.0010.020.0010.0010.0010.050.0010.04

:= Urefk

0.010.010.010.010.010.010.010.010.010.010.010.01

:=

RTL

2

2

34

5

6

7

89

10

11

12

13

0

00

1

0

1

00

0

4

0

3

=

Example 3

VHDD2

13

k

RTLk( )2∑=

:=

VHDD 5.196=

VTHD2

13

k

Uk( )2∑=

⎡⎢⎢⎣

⎤⎥⎥⎦

100⋅:=

VTHD 7.006=

THDD max 0VTHD Vthd−( )

Vthd,⎡⎢

⎣⎤⎥⎦

:=

THDD 0.401= Vthd=5%

34

0 5 10 15 20 25 300

0.01

0.020.025

0.01

Uk

Urefk

292 k

Uk

0.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.01

:= Urefk

0.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.010.01

:=

RTL

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

=

VHDD2

n

k

RTL k( )2∑=

:= VTHD2

n

k

U k( )2∑=

⎡⎢⎢⎣

⎤⎥⎥⎦

100⋅:= Vthd 5:=

VHDD 0= VTHD 5.292=

THDD max 0VTHD Vthd−( )

Vthd,⎡⎢

⎣⎤⎥⎦

:= THDD 0.058=

Example 3

Example 1: HDD>0, THDD=0Example 2: HDD=0, THDD=0Example 3: HDD>0, THDD>0Example 4: HDD=0, THDD>0

Pattern

35

•Indices may provide additional insight on diagnosing harmonic problems

•HDD provides information on individual harmonic distortion compatibility

•THDD provides information on total harmonic distortion compatibility

•Reference values can be adjusted to individual equipment or standard

•When equipment is more sensitive to waveform distortion use HDD

•When equipment is more sensitive to heating effects THDD use THDD

Steady State Grades of Power Quality

Reduced level of quality that may be the result of particular equipment connected at the site but is still adequate for this equipment operation. This level may cause problems of heating or misoperation for some equipment (e.g. motors).C - Industrial

Basic quality that should be adequate for the great majority of equipment without causing problems. This quality is designed to be consistent with the majority of industry standards.B - Basic

Highest quality for equipment with strict voltage quality and voltage regulation requirements, conditioned quality.A - Premium

DescriptionGrade

36

Qualidade de Energia – Regime Permanente – Valores Básicos

São Satisfatórios ???

Voltage THD - 95% of 10 minute values - IEC 61000-4-78%Harmonic Distortion

Max deviation for motor starting or other switching occurrences more than once per week (min single cycle rms voltage)10%Motor Starting

Pst 95% over one week period<1.0Flicker

99% 10 minute values in one week<2%Unbalance

99% 10 minute values in one week+/- 10%Voltage Regulation

Evaluation MethodRequirementCategory

Qualidade de Energia

Solução Integrada

• Matching Customer Needs with Utility Services.

• Establish An Open Environment

• Optimize Economics

37

Normas devem ajudar a determinação de níveis de compatibilidade ótima com objetivos de desempenho e econômicos

Optimizing the Investments in Reliability and Quality

Level of Quality and Reliability Provided

Cos

t

Objective - Determine optimum investment strategies from global cost perspective

Customer PQ & reliability impact costs and investment

Supply system investments to improve PQ and reliability

PowerQuality A B C dPd= + +∫∫ ( ) $A - Electric parametersB - Economic ParametersC – Society’s Infrastructure

• A Qualidade de Energia continuará a ser um aspecto de grande importância dentro da operação de sistemas elétricos, mas deve ser visto como parte de um contexto bem mais amplo do que a pureza analítica e platônica de condições ideais (abaixo a senoide pura).• Normas precisam ser contextualizadas dentro de cada sistema e comunidade.•Participação ampla de todos setores é essencial para obtenção de normas mais úteis.•Encontros como esse devem ocorrer mais freqüentemente para assegurar o sucesso desses desenvolvimentos.•Geração Distribuída irá contribuir sensivelmente para o aumento da complexidade e importância desse tópico. Precisamos nos preparar.

38

What is Power / Voltage Quality?

What is Power / Voltage Quality?

39

http://www.ece.umr.edu/courses/w03/ee304/Def/transients.htm

http://www.ece.umr.edu/courses/w03/ee304/Def/shortduration.htm

http://www.ece.umr.edu/courses/w03/ee304/Def/longduration.htm

http://www.ece.umr.edu/courses/w03/ee304/Def/interrup.htm

http://www.ece.umr.edu/courses/w03/ee304/Def/waveform.htm

http://www.ece.umr.edu/courses/w03/ee304/Def/flicker.htm

http://www.ece.umr.edu/courses/w03/ee304/Def/frequency.htm

What is Power / Voltage Quality?

Why are we concerned with PQ?

$$$$$$$$$$$$$$$$$$$$$$$$$$$

Cost Categories

Lost production

Scrap

Restart costs

Labor

Repair and replacement costs

Process inefficiency

40

Why are we concerned with PQ?

Costs Cost

Intangible Costs

Increased Business Risk

Lost Business Opportunity

Microeconomics Framework for Assessing PQ Benefit Cost

The Utility Perspective

The following block diagrams describe the proposed steps for the microeconomics of the cost assessment of power quality problems. The structure or framework is based on a four step procedure.

Step 1 - Assessment of power Disturbance Cost. This should be done based on the type of industry/process, etc. and type of disturbance. Boundary conditions should be specified to determine the actual effect of power disturbance. Direct and indirect costs, varying from production loss to reduced efficiency, should then be calculated. Step 2 - Assessment of the Cost of Mitigation. This step should compute the total cost of mitigation varying from initial monitoring and analysis to final testing of performance. Alternative options should be suggested. Step 3 - Assessment of Benefit due to Mitigation. This step should compute the direct/indirect benefits plus energy savings due to mitigation. Step 4 - Financial Computation of the Benefit-Cost - With the input from steps 1 to 3, the final assessment of the benefit-cost and payback period should be determined for the different options.

Why are we concerned with PQ? Costs Cost

41

Why are we concerned with PQ? Costs Cost

kWh not Distributed Investiment in PQuality Legal

Assessing the PQ Costfor The Utility

Total Cost Utility

Assessing The Costof Mitigation for The Utility

Total Cost of Mitigation

Level of Quality

Types of Disturbance

ImpulsesDistortions, etc.

Filtering, Power Conditioners, Motor-generator, etc.,

B

Why are we concerned with PQ? Costs Cost

42

Market Effects Return on Investiment Reduced Losses

Assessing the PQ Benefitfor The Utility

Total Benefit - Utility

Improved EfficiencyNew Customers

C

Why are we concerned with PQ? Costs Cost

Cost of Disturbance Cost of Mitigation

Financial Analysis

Option 1 Option 2

Net Benefit

Payback

A B B

Benefit due to Mitigation

Option 1 Option 2

C C

Why are we concerned with PQ? Costs Cost

43

I n t e g r a t e d M a c r o e c o n o m i c / F i n a n c i a l A n a l y s i s

Benefit CostSensitive Customer

Benefit Cost Benefit CostDistuurbing Customer Utility

Cost Benefit CurvesSensitive Customer

Cost Benefit Curves Cost Benefit CurvesDisturbing Customer Utility

Integrated Macroeconomic/Financial Analysis

Cost

Quality

Cost

Quality

Cost

Quality

Invst

Payback

Invst

Payback

Invst

Payback

Why are we concerned with PQ? Costs Cost

How does the deregulated environment affects PQ?

Reduced Investment (Operation, Maintenance, etc)

Responsibilities

Power Electronics Penetration (T, D, and User-End)

Distributed Generation (DG): Trends, Interconnection Issues

Regulating Control / Coordination Issues

Randomly Varying Sources (PV, Wind)

What is New in PQ?Instrumentation, Modeling, etc., Initiatives

44

Challenges

Distribution and Power Quality Strategic - EPRI – Roadmap - Difficult Challenges

Improved Transmission Capacity, Grid Control, and Stability

Maintain and Strengthen Portfolio of Generation Options

Accelerated Development of Carbon Capture and Storage Technologies

Achieving Low/Zero Emissions of Key Pollutants

Improved Power Quality and Reliability for Precision Electricity Users

Increasing Robustness, Resilience, and Security of Energy Infrastructure

Creation of the Infrastructure for a Digital Society

Advances in Enabling Technology Platforms

Exploiting the Strategic Value of Storage Technologies

High Efficiency End Uses of Energy

Maintaining and Improving Water Availability and Quality

Global Electrification

Development of Electricity-Based Transportation Systems

Harmônicos

Philosophy – Harmonics need to be monitored to assure that the system does not see levels of distortion that are unacceptable. The harmonic limits are established in a simplified manner, and they allow for flexibility. It is suggested that the limits should be specified in ranges indicating acceptable, requiring investigation, and unacceptable conditions. The basic system must also consider the possibility of resonance conditions due to capacitors.

Management Considerations – The system must do periodic monitoring of various locations to verify that levels are acceptable. The agent must react to situations where the harmonics are approaching unacceptable levels. Objectionable situations are to be handled on a case-by-case basis using a knowledge of the load characteristics and a study.

Technical Implementation – Various international standards exist for harmonics, but the system requires a simplified approach to allow for flexibility of various instruments. The main goals of the instrumentation are simply to flag areas of concern. When specific problems are found, then advanced instrumentation and harmonics penetration studies will be used to evaluate the best course of action.

45

Harmônicos

Breve Introdução

Nonlinear loads, such as power electronic equipment, produce non-sinusoidal current waveforms when energized with a sinusoidal voltage. They inject currents at harmonic (integer multiple of the fundamental frequency) frequencies into the system. Harmonic currents, and the voltage distortion they create as they flow through the system impedance, can reduce equipment operating reliability and service life (0-100th harmonic).

Harmônicos

Breve Introdução

Modelagem (Sources)

-Current injection model.

-Frequency- or time-domainNorton equivalent circuit model.

-Harmonic coupling matrix model.

-Time- or frequency-domaindevice model used with frequency-domain network model.

-Time-domain model.

46

Harmônicos

Breve Introdução

Modelagem (System and Loads)

Sensitivity Analysis

Harmônicos

Breve Introdução

Modelagem (System and Loads)

47

Harmônicos

Breve Introdução

Modelagem (System and Loads)

Harmônicos

Breve Introdução

Modelagem (Solution)

Harmonic Power Flow Solutions:

In this analysis, the harmonic sources are also represented as current sources. However, their magnitudes and phases are updated using an iterative scheme based on detailed (voltage-dependent) harmonic source models. Inter-phase coupling of the harmonic-sources can be modeled with good accuracy. The harmonic iteration scheme solves the network one frequency at a time. The calculated nodal voltages are then used to update the current source model. In theory, simultaneous solutions of all harmonic orders like those used in the HARMFLO program can also be developed for the multiphase analysis, but the algorithm would be extremely complex.

48

Harmônicos

Breve Introdução

Modelagem (Solution)

Harmonic Power Flow Solutions:

In this analysis, the harmonic sources are also represented as current sources. However, their magnitudes and phases are updated using an iterative scheme based on detailed (voltage-dependent) harmonic source models. Inter-phase coupling of the harmonic-sources can be modeled with good accuracy. The harmonic iteration scheme solves the network one frequency at a time. The calculated nodal voltages are then used to update the current source model. In theory, simultaneous solutions of all harmonic orders like those used in the HARMFLO program can also be developed for the multiphase analysis, but the algorithm would be extremely complex.

Harmônicos

Breve Introdução

Modelagem (System and Loads)

Geração Distribuída

Fontes e Aspectos Probabilísticos

49

Harmônicos

Breve Introdução

Aspectos Probabilísticos

Time-Varying Nature of Harmonics

THDV

0.0%

0.4%

0.8%

1.2%

2/2 2/3 2/4 2/5 2/6 2/7 2/8

THDV

The causes of variations are the continuous changes in system configurations, linear load demands and operating modes of non linear loads

An Inevitable Reality

“The variations generally have a random character and the only way one can describe the behavior of such characteristics is in statistical terms”

Harmonic Indices

Probability Functions

Statistical measures

Summation Laws

Harmonic Impedances

Time-dependent Limits

Aspects to be Considered

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

50

Harmonic phases angles are randomly varying:

Im(V5)

Re(V5)

Im(V23)

Re(V23)

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

Marginal probability density function

-4 -3 -2 -1 0 1 2 3 40

0.1

0.2

0.3

0.4

fX

X

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

51

Time ranges involved (hours, day, etc.)

Multimodal patterns

Time interval between readings and the window width

Application to estimate the thermal effects of harmonics

The time factor is completely lost and the same pdf can correspond to different time varying harmonics, with consequent different thermal responses of electrical components

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

Example: pdf of the 5th Harmonic Voltage given that its amplitude is greater than or equal to 6%

0

0.5

1

1.5

2

V5

fV5

5V 6%V

Conditional probability density functions

to reduce the volume of data to be analyzed

to represent extreme events

to introduce intriguing new statistical measures

00.5

11.5

22.5

33.5

44.5

V5

f*V5

6%V 5V

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

52

standard deviation σ

95% probability value PC95%

99% probability value PC99%

maximum value MAX

The IEC 1000-3-6 and EN 50160 refer to PC95% and MAX

average value µStatistical Measures

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

Harmonic pdfs with the same PC95% and MAX can cause different effects

µ = 0.70 σ = 0.27 µ = 0.27 σ = 0.16

x0.95 x0.95

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

53

hh

αj

αhjh UU ∑=

∑=j

hjhjh IkIαh = summation exponent dependent on harmonic order

Two semi-empirical approaches have been proposed in literature in order to allow easy and fast evaluation in practical applications such as standards

Summation Laws

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

The laws should be continuously verified to take into account:

new electronic components

the presence of unbalanced conditions

the influence of the network supplying the harmonic sources

Summation Laws

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

54

Usually, the network harmonic impedances are assigned with reference to deterministic values and without taking into account the correlation with disturbing currents

Harmonic Impedances

The network harmonic impedance has statistical behavior due to:

• network component uncertainties

• load variability (including power factor correction capacitors)

• supply system variability

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

Equipment

THDV

0.0%

0.4%

0.8%

1.2%

2/2 2/3 2/4 2/5 2/6 2/7 2/8

THDV

Up to now the studies on harmonic effects mainly (but not only) refer to static distortions

Studies are needed on harmonic effects when time-varying distortion is applied

Time-Dependent Limits

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Time-Varying Nature of Harmonics

55

IEEE 519-1992 introduced the concept of probability distribution plots to characterise variations in harmonic levels.

•A reasonable method of using these types of plots to evaluate harmonic levels would be to compare the steady state harmonic limits with the measured harmonic level that is not exceeded 95% of the time (the 95% probability point). This is consistent with the evaluation of compatibility levels in IEC standards.

•In order to further develop this topic the IEEE Probabilistic Aspect of Harmonics Task Force is preparing a proposal for the Std. 519 in which the time-varying nature of harmonics voltages are considered in the establishment of the limits. •Any limits on the short duration harmonic levels should be based on the possible impacts of these harmonic levels. Effects such as metering error and equipment ageing are the accumulated result of harmonic levels over time. Other effects include the sensitive electronics to short burst of high harmonic levels or certain types of waveform distortions.

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Proposition For IEEE 519

Recommendations are being prepared, with suggested procedures and values to be discussed by the members of the Std. 519 Revision Task Force. These recommendations will be consistent with the 519 Application Guide.

Probability distributions and short-term disturbance limits shall be established.

The “continuous limits” could be taken as, for example, the 95% probability limit.

The values will be established based on the impact of short-term harmonics on different equipment.

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Proposition For IEEE 519

Recommendations are being prepared, with suggested procedures and values to be discussed by the members of the Std. 519 Revision Task Force. These recommendations will be consistent with the 519 Application Guide.

Probability distributions and short-term disturbance limits shall be established.

The “continuous limits” could be taken as, for example, the 95% probability limit.

The values will be established based on the impact of short-term harmonics on different equipment.

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Proposition For IEEE 519

56

T H D B i n s ( % )

Freq

uenc

y

0

5

1 0

1 5

2 0

2 5

3 0

3 5

4 0

4 5

5 0

0 . 7 0 . 8 0 . 9 1 1 . 1 1 . 2 1 . 3 1 . 4 1 . 5 1 . 6 1 . 7 1 . 8 1 . 9

0 . 0 0 %

1 0 . 0 0 %

2 0 . 0 0 %

3 0 . 0 0 %

4 0 . 0 0 %

5 0 . 0 0 %

6 0 . 0 0 %

7 0 . 0 0 %

8 0 . 0 0 %

9 0 . 0 0 %

1 0 0 . 0 0 %S i t e 1 0 9 2 T H D H i s t o g r a mJ u n e 1 9 - J u n e 2 6 , 1 9 9 2

C o u n t = 3 0 5M i n i m u m = 0 . 7 3 9

M a x i m u m = 1 . 9 4 9R a n g e = 1 . 2 1 1

M e a n = 1 . 4 0 6M e d i a n = 1 . 4 8 9

S t a n d a r d D e v i a t i o n = 0 . 3 1 8S t a n d a r d E r r o r = 0 . 0 1 8 2

V a r i a n c e = 0 . 1 0 1S k e w n e s s = - 0 . 5 2 1

K u r t o s i s = - 0 . 7 7 7

Table 1 – Short-Term Limits Short-Time

Limits

Duration of Disturbance

A x Continuous Limits

a1 sec < T < b1 sec

B x Continuous Limits

b1 sec < T< a2 min

C x Continuous Limits

a2 min < T< b2 min

THD V

0.0%0.4%0.8%1.2%

2/2 2/3 2/4 2/5 2/6 2/7 2/8

THDV

Harmônicos

Breve Introdução

Aspectos Probabilísticos - Proposition For IEEE 519

Histogram and cumulative distribution of THD levels for a week long measurement.

138kV bus voltage THD as a function of time

Harmônicos

Breve Introdução

Aspectos Probabilísticos

57

Drawing of cumulative distribution (Ttotal) and the maximum duration and maximum duration of individual burst (Tmaximum) for a harmonic measurement. The curve also includes a conceptual limit for short term harmonic levels.

Harmônicos

Breve Introdução

Aspectos Probabilísticos

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Monitoring and Analysis to Evaluate Compliance

Monitoring to characterize system performance

Monitoring to characterize specific problems

Monitoring as part of an enhanced power quality service

58

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Monitoring Program Components

Power quality and/or energy demand monitors

Data storage

Download computers

Web or company Intranet server

Some viewgraphs used with permission of Mark McGranaham and

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Why monitor power systems?

Benchmark system performance levels (understand power quality that can be expected, Allows option for expanded power quality services)

Reliability reporting (reliability defined based on customer impacts)

Prioritize system investments

Information service for customers

Identify and solve problems

Improve system operations and reliability

59

Example of SystemMonitoring Concept

Transmission

DistributionSubstation

SubstationMonitoring

System

CustomerMonitoring

System

CustomerMonitoring

System

MonitoringDatabase

Local Network

Data Collection Data Collection

Database Management/Local Data Analysis

CorporateIntranet

Internet/World Wide Web

Power Quality/Energy

Information Service

Power Quality/Reliability

Performance andData Analysis

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Harmônicos

Breve Introdução

Important components for a system Open architecture

Systems should allow integration of different technologies within utility and customer networks

Power Quality Data Interchange Format (PQDIF)IEEE Standard 1159.3

Web-based access to the informationIntelligent applicationsAutomated reporting functions

60

Harmônicos

Breve Introdução

Benchmarking – First we need to understand existing PQ and reliability

Reliability is more than SAIFI and SAIDI for many customers.

We have to understand the expected system performance before establishing regulations or developing contracts.

Harmônicos

Breve Introdução

Documenting performance for continuous PQ variations

Voltage regulationUnbalanceFlickerHarmonics

Compatibility level

Assessed level

Disturbance magnitude

time

Equipment immunity test levels

Utility planning levels

61

Harmônicos

Breve Introdução

The concept of compatibility levels

Harmônicos

Breve Introdução

Monitoring to improve operations & reliability

Fault locationCapacitor bank performance assessment Voltage regulator performance assessment DG performance assessment Cable fault identifier Arrester failure identifierTransformer loading assessment

This is where the real financial return for system monitoring comes in

62

Example –Identifying harmonic problems

Power factor correction equipment can result in resonances that magnify harmonic levels. The monitoring system can identify and alarm based on these conditions before they cause equipment failures.

-600

-400

-200

0

200

400

600

0.00 0.02 0.04 0.06 0.08

Example Voltage Waveform showing Voltage Distortion Problem

Vol

tage

( V

)

Time ( s)

0

20

40

60

80

100

120

0 2 4 6 8 10

Harmonic Components of the Voltage Waveform

Vol

tage

(%)

Harmonic Component

Harmônicos

Breve Introdução

Monitoring to improve operations & reliability

Prioritizing new applicationsFaults

Fault locationFault typeCauses of faultsTrends of fault locations indicating problemsIncipient faults for cable and arrester failures

Protective Device OperationsTimingCoordination problems (fuses, reclosers, sectionalizers, etc.)Misoperation identification

BreakersPole spanTimingDuties and maintenance requirement

Harmônicos

Breve Introdução

Monitoring to improve operations & reliability

63

Capacitor operations

Capacitor location

Identification of blown fuses or unbalanced operation

Severity of transients

Breaker restrikes

Operation of transient control technology (e.g. synchronous closing)

Magnification concerns

Impacts on customers

Transformer evaluation

Loading issues

Harmonic impacts

Regulator performance and maintenance requirements

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Distributed generation applications

Energy monitoring

Operation of protection systems and coordination with power system protection

Harmonic impacts

Impacts on voltage regulators

Power factor issues

System performance assessment and control

Power factor control

Harmonic resonance identification and control

Feeder loading

Voltage regulation

Harmônicos

Breve Introdução

Monitoração and Instrumentação

64

Prioritizing new interfaces – Integrating with current systems

Smart RelaysSchweitzerABB…

Reclosers (Cooper)Digital Fault Recorders

HathawayRochester…

Transformer MonitorsSCADA Systems…

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Web interface to the substation -monitoring system

Harmônicos

Breve Introdução

Monitoração and Instrumentação

65

We can manage the data for you www.powermonitoring.com

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Harmônicos

Breve Introdução

Monitoração and Instrumentação

66

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Harmônicos

Breve Introdução

Monitoração and Instrumentação – System Configuration

67

Harmônicos

Breve Introdução

Monitoração and Instrumentação – Data Analysis

Harmônicos

Breve Introdução

Monitoração and Instrumentação – Analytical Methods

68

•Performance benchmarking is very important but difficult to justify economically

•Power system monitoring can have benefits in improving operational reliability and efficiency – these benefits can easily justify the monitoring system

•Reduces time to locate and repair faults

•Identification of equipment problems (possibly avoiding outages and improving reliability)

•More efficient scheduling

•Don’t cut too many corners – build the system so that it can take advantage of new technologies and applications (detailed waveform recording, communication systems, open architecture, etc.)

•Should be Internet-based for interfacing, ease of use, and ongoing support

Harmônicos

Breve Introdução

Monitoração and Instrumentação

Harmônicos

Breve Introdução

Normas / Recomendações (IEEE 519)

Current Distortion Limits (in % of IL) for General Distribution Systems (120-69,000 V)

Current Distortion Limits (in % of IL) for General Sub-Transmission Systems (69,001-161,000 V)

69

Current Distortion Limits (in % of IL) for General Transmission Systems (>161,000 V)

Voltage Distortion Limits (in % of V1)

Harmônicos

Breve Introdução

Normas / Recomendações (IEEE 519)

GENERAL PROCEDURE FOR APPLYING HARMONIC LIMITS

Step 1: Choose the point of common coupling,

Step 2: Characterize the harmonic-producing loads,

Step 3: Assess power factor correction needs,

Step 4: Calculate expected harmonics at the PCC,

Step 5: Design and implement solutions (if needed), and

Step 6: Verify performance with measurements.

Harmônicos

Breve Introdução

Normas / Recomendações (IEEE 519)

70

2.5 > Wi >0.5

Harmônicos

Breve Introdução

Normas / Recomendações (IEEE 519)

1. Modeling of network components such as overhead lines, cables, transformers, etc. (The analyst has some flexibility in selecting the level of detail needed; sensitivity studies should be considered to determine which degrees of detail can be avoided in any particular study.)

2. Modeling of various nonlinear loads including predefined models and the capability for user-defined models based on measured or typical data. (It is left to the analyst to determine what degree of sophistication is required, especially if time-domain simulation techniques are to be used.)

3. Modeling of power factor correction capacitors should be “built in” to any software being considered. (The representation of the equivalent capacitance is the most important requirement; other details are somewhat insignificant for limit compliance evaluations.)

4. Modeling of utility system equivalents should be straightforward. (In an advanced study, the analyst should consider the capability to represent the frequency dependence of network equivalents.)

Harmônicos

Breve Introdução

Normas / Recomendações (IEEE 519)

71

519 Revisions

Update sponsors– PES T&D Committee– IAS IPC CommitteeIntroduction– Establish applicability of 519– Demonstrate PCC via single-line diagramDefinitions– Update according to content modifications as

appropriateChapter 4 “Harmonic Generation”eliminated– Include bullet list of “causes” in introduction

72

Chapter 5 “System Response Characteristics” eliminated– Add cautions in introduction regarding the

possibility of resonances creating compliance problems

– Also caution that customer-side modifications that create undesirable resonances are customer’s responsibility to fix

This is part of the “shared responsibility” flavor of 519

Chapter 6 “Effects of Harmonics”significantly reduced (to general information) and moved to an annex– Update TIF based on Std. 776-1992 (R2003)– Include this material in 519.1 “next time” and

then remove from future 519 revisions

Chapter 7 “Reactive Power Compensation and Harmonic Control” eliminated– Information is either well understood now,

widely documented in other literature, or not necessary for a “limits” document

73

Chapter 8 “Analysis Methods” mostly eliminated– Provide up-to-date bibliography– Move Section 8.5 “Notching” into annex– Use Figure 8.7(a) (or similar) in introduction

to define PCC and related conceptsChapter 9 “Measurements” completely re-written– Endorse IEC 61000-4-7 (2ed) and 4-30– Provide sufficient material to understand

meter outputs and on-line statistics– Harmonize with 1159 as necessary

Chapter 10 “Recommended Practices for Individual Consumers”– Make sure PCC is clear in introduction and

again here519 is an interface standard, not an equipment standard

– Section 10.3 moved to annexUpdate with additional info from 519-1981

– Section 10.4: remove “value added” for higher pulse order

If 5th, 7th (11th, 13th, etc.) are below 25%, then user gets credit (1.5x, 1.75x, 2.0x, etc) regardless of how the <25% levels were obtained

74

Chapter 10 “Recommended Practices for Individual Consumers”– Section 10.4: Make sure that definition of load

current (IL) is clear– Current limit tables

Justify limits for generation to avoid the “negative load” conceptDo not eliminate even-order limitsMake each table a full page with common and consistent footnotes, explanations, and disclaimers…Interharmonics should not create objectionable lamp flicker or other undesirable or damaging effects

– Interharmonic limit curve based on flicker in annex

Chapter 10 “Recommended Practices for Individual Consumers”– Express limits using 4-7 & 4-30 measurement

protocol95th percentile of the 10 minute values less than the given limits over a period of one week99th percentile of the 10 minute values less than 1.5 times the given limits (over one week)99th percentile of the 3 second values less than 2.0 times the given limits over one (each) day

– Section 10.4.1 “Transformer Heating” reduced to a table footnote

75

Chapter 10 “Recommended Practices for Individual Consumers”– Section 10.4.2 “Probabilistic aspects”

eliminatedCaptured using 4-7 & 4-30 protocols

– Section 10.5 “flicker” eliminated

Chapter 11 “Recommended Practices for Utilities”– Put chapter in front of “customer limits”

chapterEmphasize that voltage problems are what are trying to be avoidedCurrent limits depend on system and economics

– Section 11.2 “addition of harmonics”eliminated

– Section 11.3 “short duration” eliminatedCaptured using IEC protocol

– Section 11.4 eliminated

76

Chapter 11 “Recommended Practices for Utilities”

– Section 11.5 “voltage limits” focused on compatibility concept

Refer to “effects” material that was moved to annex

– Limit table (Table 11.1)Add new row for <1kV (5% & 8%)Remind about PCC, especially for <1 kV case95th percentile of 10 minute values less than limit values over one week99th percentile of 3 second values less than 1.5 times the limit over one dayAdd new limits for h>13 for <1kV and 1-69 kV rows

– 0.5 times existing limits for these higher orders

Chapter 11 “Recommended Practices for Utilities”– Possible additional modification

Changing rows from 69-161 kV and >161 kV to 69-230 kV and > 230 kV???

– Section 11.6 “interference with communications” moved to annex with other TIF material

77

Chapter 12 “Recommended Practices for Utilities”– Almost all 519.1 material– Capture philosophy in introduction

New Structure– Expanded introduction focusing on why 519 is needed

(effects) and where it is to be applied (PCC definition)Very limited information on “what is required” and “how” to apply it

– This is the domain of 519

– Measurement protocol (should majority be in annex?)IEC 61000-4-7 & 61000-4-30

– Voltage distortion limits– Current distortion limits– Multiple annexes with “good, old” and “good, new”

material– Expanded bibliography

78

Harmônicos

Breve Introdução

Índices Harmônicos

Harmônicos

IEC 61000-3-6 Voltage Harmonic Planning Levels

79

At the PCC, system owners or operators should limit harmonic voltages as follows:

• Daily 99th percentile very short time (3 second) values should be less than 1.5 times the values given in Table 5-1.

• Weekly 95th percentile short time (10 minute) values should be less than the values given in Table 5-1.

All values should be in percent of the rated power frequency voltage at the PCC. Table 5-1 applies to voltage harmonics whose frequencies are integer multiples of the power frequency.

Interharmonics – IEEE 519For harmonic components which are not integer multiples of the power frequency, system owners or operators should limit the weekly 95th percentile short time harmonic voltages to the values shown graphically in Figure 5-1 up to 120 Hz. Depending on the voltage level, the integer harmonic limits in Table 5-1 may be more restrictive and should be used. The portions of the 0-120 Hz range where the integer harmonic limits of Table 5-1 are more restrictive are appropriately labeled in Figure 5-1. The numerical values corresponding to Figure 5-1 are given in Table 5-2 for voltages at the PCC less than 1 kV. It is important to note that the recommended voltage interharmonic limits are based on lamp flicker assessed using the measurement technique described in IEEE Std. 1453 and IEC Std. 61000-4-15. These voltage interharmonic limits correlate with a short-term flicker severity Pst value equal to 1.0. The recommended limits in Figure 5-1 are not based on the effects of interharmonics on other equipment and systems such as generator mechanical systems, signaling and communication systems, and filters. Due consideration should be given to these effects and appropriate limits should be developed on a case-by-case basis using specific knowledge of the supply system and connected user loads.

80

81

COMPARISON AND CONTRAST: IEEE VS. IEC LIMITS

A. Driving principle

The basic premise of the IEEE harmonic limits is a shared responsibility between utility and customer. All customers are granted some reasonable share of the system’s ability to absorb harmonics.

If voltage distortion problems exist with all customers within their current limits, the utility is responsible for taking action to restore voltage quality.

The IEC approach is based on assigning current limits that are more rigorously derived from voltage quality targets and is designed to insure that if all customers are within their individual limits, then system-level voltage quality problems will not exist.

COMPARISON AND CONTRAST: IEEE VS. IEC LIMITS

B. Voltage harmonic limits

Both standards provide voltage harmonic limits. The IEEE voltage harmonic limits are constant across all frequencies whereas the permissible voltage harmonic magnitudes decrease with frequency in the IEC.

C. Current harmonic limits

Current harmonic limits are the centerpiece of IEEE 519-1992, but the limit values are only loosely correlated with system voltage targets. The IEC avoids giving current harmonic limits in a general sense, preferring that these limits be more rigorouslyderived based on voltage limits and system impedance characteristics.

82

COMPARISON AND CONTRAST: IEEE VS. IEC LIMITS

D. Even-order harmonics

IEEE 519-1992 does not specifically address even-order harmonics for voltage (all voltage harmonics are treated equally), but does recommend that even-order current harmonics be limited to 25% of the values for corresponding odd-order harmonics. The IEC specifically addresses evenorder voltage harmonics and appears to allow greater evenordercurrent harmonic emission (depending on system impedance characteristics) than IEEE.

E. Non-characteristic harmonics

Both IEEE and IEC consider harmonics in a general sense, without regard to characteristic harmonics generated by certain types of equipment (e.g., six-pulse rectifiers generating characteristic harmonics at the 5, 7, 11, 13, etc., frequencies). IEEE does, however, offer a “credit” for higherpulseorder equipment provided that non-characteristic harmonics (for the equipment in question) remain low.

COMPARISON AND CONTRAST: IEEE VS. IEC LIMITS

F. Time-varying harmonics

IEEE suggests that the current harmonic limits may be exceeded by 50% for short periods of time. IEC rigorously addresses time-varying aspects of harmonics by utilizing percentiles (e.g., 95th and 99th) for very short time (3 second) and short time (10 minute) aggregated measurements. In addition, IEC provides a multiplyingfactor by which harmonic limits may be increased when considering very short time emissions.

G. Interharmonics

IEEE 519-1992 does not address interharmonics. IEC 61000-3-6 addresses interharmonic voltage limits by recommending a frequency-independent limit of 0.2% so as to avoid problems with lamp flicker and ripple control, signaling, and communications equipment.

83

IEEE P1547.1 Standard for Conformance Tests Procedures for Equipment Interconnecting Distributed Resources with Electric Power Systems

Scope This standard specifies the type, production, and commissioning tests that shall be performed to demonstrate that the interconnection functions and equipment of a distributed resource (DR) conform to IEEE Standard P1547.

Purpose Interconnection equipment that connects distributed resources (DR) to an electric power system (EPS) must meet the requirements specified in IEEE Standard P1547. Standardized test procedures are necessary to establish and verify compliance with those requirements. These test procedures must provide both repeatable results, independent of test location, and flexibility to accommodate a variety of DR technologies

Standards currently under development are:•P1547 - Draft Standard for Interconnecting Distributed Resources with Electric Power Systems •P1547.1 - Draft Standard for Conformance Test Procedures for Equipment Interconnecting Distributed Resources with Electric Power Systems •P1547.2 - Draft Application Guide for IEEE P1547 Draft Standard for Interconnecting Distributed Resources with Electric Power Systems •P1547.3 - Draft Guide for Monitoring, Information Exchange and Control of DR Interconnected with EPS

84

Harmônicos

Debates – Mesa Redonda

Harmônicos

Contratos e Seguros

Harmonic Distortion.IEEE 519-1992 describes the responsibility between the customer and the distribution system supplier in controlling harmonic distortion levels. The distribution company is responsible for the voltage distortion and the customer is responsible for harmonic currents being created by nonlinear loads within the facility.

Involvement of Multiple Entities

Transmission Provider

Local Distributor

Independent Power Producers

Retail Marketers, Energy Companies

End User

85

Harmônicos

Contratos e Seguros

Requirements for Power Quality Contracts

· Reliability/power quality concerns to be evaluated

· Performance indices to be used

· Expected level of performance (baseline)

· Penalty for performance outside the expected level and/or incentives for performance better than the expected level (financial penalties,performance-based rates, shared savings, etc.)

· Measurement/calculation methods to verify performance

· Responsibilities for each party in achieving the desired performance

· Responsibilities of the parties for resolving problems

Harmônicos Contratos e Seguros

Power Quality Contracts in a Restructured Competitive Electricity Industry, Barry W. Kennedy – Bonneville Power, Administration, Portland, OR 97209, Mark McGranaghan – Electrotek Concepts, Knoxville, TN 37923 -http://www.dranetz-bmi.com/pdf/contracts.pdf

86

Harmônicos

Contratos e Seguros

Harmônicos

- Aspectos Econômicos / Custos

87

Debates – Mesa Redonda

Questions for Discussion and Deliberation

What is Really Power Quality? Evaluate Definitions

How Should Harmonics Be Treated (Rigid / Flexible Approach)?

How should the probabilistic nature be incorporated?

What about costs?

How does the deregulated environment affects PQ?

Topics for future research and development.

Other Questions and Issues?

Example – What was causing this event?

Debates – Mesa Redonda

Quiz

88

More clues from the current waveform

Debates – Mesa Redonda

Quiz

Problem -- found before failure!

Transformer tap changing mechanism

Debates – Mesa Redonda

Quiz

89

Distúrbios na Tensão-Breve Introdução

-Definições (Sags, Swells, Flutuações de Tensão, etc)

-Instrumentação

Voltage sags are typically characterized by the minimum rms voltage and the duration of the sag.

Distúrbios na Tensão

-Breve Introdução

- Definições (Sags, Swells, Flutuações de Tensão, etc)

- Instrumentação

Benchmarking voltage sag performance

Basis for evaluating ongoing system performanceBasis for evaluating economics of power quality improvement

options Basis for implementing PQ-based contractsBasis for attracting customers that are concerned about PQ levelsCan be basis for standards

90

Distúrbios na Tensão

- Breve Introdução

- Definições (Sags, Swells, Flutuações de Tensão, etc)

- Instrumentação

Voltage sag performance on medium voltage systems

Benchmarking Project SARFI-70 SARFI-80 SARFI-90

Power Grid - Singapore 7.8 10.6 13.2

United States (DPQ Project) 17.7 27.3 49.7 Europe – Mixed Systems (UNIPEDE) 44.0 NA 103.1 Europe – Cable Systems (UNIPEDE) 11.0 NA 34.6

South Africa (NRS-048 indicative levels) 47.0 78.0 153.0

Distúrbios na Tensão

-Sources of Voltage Sags and Interruptions

-Estimating the Voltage Sag Performance

-Area of Vulnerability

-Equipment Sensitivity

-Magnitude

-Magnitude and Duration

-Other than Magnitude and Duration

-Transmission System Performance

-Utility Distribution Systems Sag Performance Evaluation

91

Voltage SagsVoltage sags and other system disturbances are emerging as important power quality concerns, due chiefly to the economic problems that they cause for consumers. Voltage sags can be caused by faults on the distribution systems or on the transmission system (basic grid). It is important to understand how faults on the basic grid contribute to the overall voltage sag performance experienced by an end user.

F a u l t s o n O w n C i r c u i t

2 3 %

F a u l t s o n P a r a l l e l C i r c u i t s

4 6 %

F a u l t s o n T r a n s m i s s i o n

S y s t e m3 1 %

Example of the breakdown of voltage sag performance at an end user location illustrating the relative causes of voltage sags between the transmission system and the distribution system.

Voltage Sags and Momentary Interruptions

With regards to voltage sags, the basic principles are:

Philosophy – The system should track and evaluate faults on the system that cause voltage sags on the basic grid. There is a need for a methodology both to measure sags and to calculate voltage sag performance from a historical data base of the system faults, in order to get benchmarking data for the system and inform the results to the customers/agents.

Management Considerations – The system is able to track the number of faults (per 100 km of line) as the most meaningful control action. This is similar to the continuity issue. It can also provide information to customers/agents. This is the best measure of the transmission system performance since it is not dependent on the system topology.

Technical Implementation – Issues regarding the specific characterization procedures for voltage sags, the monitoring equipment requirements, the location of monitors, and the analysis of the data are all being studied in the international community at this time

92

SARFI

The “System Average RMS (Variation) Frequency Index” or “SARFI” was developed by EPRI to describe voltage sag performance. It has been adopted by several U.S. utilities, and also utilities in the U.K. and Singapore. It is recommended for the basic grid in Brazil.

The SARFI index is usually expressed as a function of equipment sensitivity (or minimum phase magnitude). For example a

SARFI70 Indicates the annual number of voltage sags where the retained voltage (on the minimum phase) is less than 70%. This is equivalent to an event when the voltage is 30% below the nominal (prefault voltage).

SARFI90 Indicates the annual number of voltage sags where the retained voltage (on the minimum phase) is less than 90%. This is equivalent to an event when the voltage is 10% below the nominal (prefault voltage).

SARFICBEMA Indicates the annual number of voltage sags where magnitude and duration of the event is outside the CBEMA equipment sensitivity tolerance curve.

What are the monitor requirements? What is the required sampling rate for the waveform (e.g. 16 samples per cycle)?

The general requirements are that the monitor must have good time synchronization. It should establish a “floating nominal” for the triggering of events – given the nature of the system. It must cross-trigger all phases during an event. It should aggregate the phase measurements. It should provide the data in a format (IEEE 1159.3) that allows software programs to exchange and analyze the data.

The instrument could have as few as 16 samples per cycle to do a good job of trending rms voltage versus time. This would be enough for voltage sag characterization. However, many utilities find that the waveforms from the sag help identify the cause of the fault or the performance of the system protection operation. A faster sampling rate (say 128 sample per cycle) will give this extended information.

93

What are the central data analysis requirements?

1That the data is secure. Data storage and archiving are important.

2That the data is accessible. The internet/intranet technologies are important for access.

3That the data is up to date. Data retrieval from the instrument must be considered, especially if there is a wide system event when all of the sites will be reporting.

4That the data is summarized in a meaningful way. This process may or many not be automated.

5That system alarms or e-mails or pages can be sent. Many instruments will natively have this capability in the future.

Should voltage sag limits be developed for the system?

This is not recommended. There have been a number of attempts todevelop limits for voltage sag performance that can be applied to the power system at both transmission and distribution levels. These are very problematic to develop and they have limited benefit to the customer. Any limits that must be developed will necessarily be based on the worst performing parts of the system. This will result in a very pessimistic assessment of the voltage sags to be expected.

Guidelines for the transmission system in terms of expected fault performance of transmission lines and transmission systems is a much better idea. These guidelines would be expressed as expected numbers of faults/100 km/year.

94

What are the important parameters affecting voltage sag performance?

Fundamentally, voltage sag performance is affected by end user equipment sensitivity. From a utility perspective, the performance is affected by the nature and location of faults. The pattern of generation at the time of the fault is also a factor in voltage sag levels. The number of phases involved in the fault is very important. Sag shifting transformations (such as delta-wye transformer banks) between the fault and the measurement point will change the characteristics of the voltage sag.

Estimating voltage sag performance based on fault performance levelsThe voltage sag performance for a given customer facility will depend on whether the customer is supplied from the transmission system or the distribution system. For a customer supplied from the transmission system, the voltage sag performance will depend on only the transmission system fault performance. On the other hand, for a customer supplied from the distribution system, the voltage sag performance will depend on the fault performance on both the transmission and distribution systems. Voltage sag performance at a system location can be estimated using records of the system fault performance and accurate short circuit models of the system. The analysis starts with the determination of the “area of vulnerability”. This is the area where faults on the system can cause voltage sags that may result in equipment misoperation. Short circuit programs such as ASPEN One Liner can calculate the voltage throughout the system resulting from faults around the system, essentially providing the area of vulnerability information.

Example of the area of vulnerability concept.

95

TLine Disturbances Vs Voltage Level

0 2 4 6 8 10 12 14

69 kV

110-138 kV

220-230 kV

440-500 kV

Events per 100 mile / Year

Example of fault performance statistics (from recent survey of transmission system fault performance levels from around the world).

Example of summarizing expected voltage sag performance at a system interface point.

96

0

10

20

30

40

50

60

70

Num

ber o

f Eve

nts

per Y

ear

Interruptions < 50% < 60% < 70% < 80% < 90%Minimum Sag Voltage

Expected Voltage Sag Performance

Distribution

Transm ission

Example of summarizing voltage sag performance at typical SARFI threshold values.

Example of characterizing voltage sag events with actual waveforms.

97

Example of characterizing voltage sag events with rms vs. time plots for the event.

Example of characterizing voltage sag events by summarizing magnitude and duration of events with respect to equipment sensitivity (ITIC curve).

98

0 to 10

30 to 40

60 to 7090 to 100

1 cy

c2

cyc

3 cy

c4

cyc

5 cy

c6

to 1

0 cy

c10

to 2

0 cy

c20

to 3

0 cy

c30

to 6

0 cy

c

050

100150200250300350400450500

Cou

nt

Magnitude

Duration

Magnitude Duration RMS Events

Example of characterizing voltage sag performance using a three dimensional chart showing the count of events with magnitude and duration.

S a g T y p e DO n e - p h a s e f a u l t , p h a s e s h i f t

S a g T y p e BO n e - p h a s e f a u l t , n o p h a s e s h i f t

S a g T y p e CT w o - p h a s e f a u l t , p h a s e s h i f t

S a g T y p e ET w o - p h a s e f a u l t , n o p h a s e s h i f t

S a g T y p e AT h r e e - p h a s e f a u l t

Characterization of voltage sag events according to the sag type. The magnitudes of the voltage on each phase and the phase shift must be determined for each voltage sag event in order to determine the sag type. This information helps to identify the fault location and the type of fault that caused the sag.

99

Managing system disturbances

It is not recommended to establish limits for voltage sags. Limits have the effect of establishing mediocre performance for the entire system, and not to improve performance. Rather it is recommended that the system be monitored for the causes of faults, and those cause addressed by maintenance action. The lines that have a high incidence of faults be investigated for ways to improve their fault performance. The equipment that has a higher failure rate be replaced or new specifications may be developed. This process involves the establishment of a database to detect these problems, and aggressive maintenance action to resolve those causes.

Some useful tools of the PQMS for implementing the management system include the following:

Trends of voltage sag performance over time.Reports of voltage sag performance across the system.Correlation of voltage sag events with important system parameters and system conditions (e.g. lightning events, breaker operations, equipment failures, tree contacts, other causes, etc.)Summaries of voltage sag performance by region, voltage level, short circuit capacity, etc.

Example of trends illustrating voltage sag performance over time (SARFI indices).

100

Comparison of UI Substation's SARFI 70 performance of the last 12 months vs. their 3 year average

0

2

4

6

8

10

12

14

16

ALLINGS CROSSIN

G

ANSONIA

ASH CREEK

BARNUM

BROADWAY

CONGRESS

EAST SHORE

ELMWEST

HAWTHORNE

INDIA

N WELL

JUNE ST.

MILL RIV

ER 1

MILL RIV

ER 2

MILVON

MIX A

VENUE

NORTH HAVEN

OLD TOWN

PEQUONNOCK

QUINNIPIA

C

SACKETT

TRAP FALLS

WATER ST.

WOODMONT

BAIRDA

BAIRDB

CONGRESS NEW

Substation Name

Num

ber

of ti

mes

whe

n Su

bsta

tion'

s Bus

Vol

tage

was

less

th

an 7

0% o

f Nom

inal

per

365

day

s

SARFI70 from Distribution Events 3 years average SARFI70 from Trasmission Events 3 years averageSARFI70 from Distribution Events during the last four Quarters SARFI70 from Trasmission Events during the last four Quarters

Example of comparing voltage sag performance at different substations. The chart shows the breakdown of events caused by transmission faults vs. distribution faults and compares the three year average performance with the last year’s performance for each substation.

ENV SENOKO INCINERATOR

SENOKO

QUEENSTOWN

LABRADOR

LABRADOR

ADMIRALTY WEST

PULAU BUKOM

PIONEER SECTOR

UPPER JURONG

GUL CHANNEL

PIONEER RD

TUAS P/S

NORTHERN TUAS

S ERAYA CHEMICALS

PANDAN

PULAU SERAYA

PULAU SERAYA S/H

PULAU SAKRA

PULAU AYER CHAWAN

NEW MOBIL

PULAU AYER MERBAU I

PULAU AYER MERBAU II

PULAU MERLIMAU

JURONG HARBOUR

JURONG PIER

JURONG PIER

JURONG WEST

INTERNATIONAL RD

CHOA CHU KANG

UPPER JURONG

JLN BAHAR

NTU

BUONA VISTA

NUS AYER RAJAH

BUKIT PANJANG

AYER RAJAH

JURONG EAST

CLEMENTI

BUKIT BATOK

CHOA CHU KANG

DUNEARN

CHOA CHU KANG NEW TOWN

MARSILING

MANDAI

230kV SUPPLY ZONES

OCTOBER 1999

ALJUNIED

MARINA CENTRE

KALLANG BASINKG JAVA

OUTRAM

NEW ARMENIAN ST

SOMERSET

STAMFORD RD

ΣΕΝΤΟΣΑ

TK BLANGAH

ΠΥΛΑΥ ΒΡ ΑΝΙ

KG BAHRU

ST JAMES

GRANGE RD

HENDERSON

ANN SIANG HILL

TRAFALGAR

GEORGE ST

RAFFLES

CRAWFORD

CHANDERRD

SUNTEC CITY

THOMSON

BRIGHT HILL

KALLANG BASIN

KG JAVA

TOA PAYOH

SERANGOON NORTH

ANG MO KIO

BISHAN

MARINE PARADE

TG RHU

YASIN

PAYA LEBAR

AIRPORT

EUNOS

PAYA LEBAR

HOUGANG

AIDA

BEDOK

TAMPINES

TAMPINES

YISHUN

ADMIRALTY WEST

CHANGI AIRPORT

CHANGI

TAMPINES NEW TOWN

PASIR RIS

PAYA LEBAR

SOXAL

NISM

TAMPINES AVE 10

PANDAN LOOP

TUAS SOUTH AVE 3

WOODLANDS LINK

TUAS INCINERATOR

SenokoSARFI 90 – 11.2SARFI 80 – 6.1SARFI 70 – 4.6

Paya LebarSARFI 90 – 13SARFI 80 – 12.1SARFI 70 – 7.1

TampinesSARFI 90 – 13.2SARFI 80 – 10.9SARFI 70 – 9.2

Kallang BasinSARFI 90 – 13.2SARFI 80 – 11SARFI 70 – 6.6

Kg JavaSARFI 90 – 12.9SARFI 80 – 10.7SARFI 70 – 6.5

LabradorSARFI 90 – 14.7SARFI 80 – 11.1SARFI 70 – 6.8

Ayer RajahSARFI 90 – 13.4SARFI 80 – 10.9SARFI 70 – 8.0

P SerayaSARFI 90 – 13.3SARFI 80 – 11SARFI 70 – 9.5

Jurong PierSARFI 90 – 13.7SARFI 80 – 10.7SARFI 70 – 10.6

Upp JurongSARFI 90 – 12.9SARFI 80 – 11SARFI 70 – 6.5

Choa Chu KangSARFI 90 – 13.3SARFI 80 – 10.8SARFI 70 – 10.7

22kV SARFI MAP

Example of presenting expected voltage sag performance as SARFI indices for different parts of the system (SARFI Map).

101

We recommend that an annual report of expected voltage sag performance (and reliability performance) be developed that can be used by distribution companies and other agents to incorporate into overall expected voltage sag performance at customer locations. Seminars and workshops should be held on an annual basis to discuss various topics related to power quality concerns:

--Problems being experienced by customers as a function of specific types of power quality variations.

--Costs of power quality impacts.

--New solutions available to help improve performance (with economics).

--System performance expectations.

--System interaction issues.

Distúrbios na Tensão

-Fundamental Principles of Protection

102

Quality of Supply Guarantee

Outage– Complete loss of ac power (voltage

less than 10% of nominal) for 1 minute or more.

– Used past five years of outage data to obtain an average

Utility Payments to Customer

Every outage over the target number– Target: ½ an outage every year– after four years, one outage every four

years– rolling twelve month period

Payments will vary by facility– $2,000 - $326,000 per outage

103

DefinitionsCustomer “definition” of an outage– Includes voltage sags

Magnitude vs Duration Scatter Plot with CBEMA Overlays

10-1 100 101 102 103 104 0

25

50

75

100

125

150

Duration (Cycles)

Voltage Magnitude (%)

Total Events:Events Below:Events Above: Below CBEMA: Above CBEMA:

31 31 0 3 0

Voltage sag (dip) agreement

Had to monitor the system for two years before voltage sags could be included Had to determine how to count events such as circuit reclosing, multiple phases, or minor events

104

Electric utility deregulationRe-regulation ? – Privitisation– Corporatization

Financial returns instead of the “public good”Need for minimal standards (benchmarking)

3 - OverallProtection

Inside Plant

CONTROLS

MOTORS

OTHER LOADS

32

1

2 - ControlsProtection

1 - EquipmentSpecifications

INCREASING COST

UtilitySource

4

4 - Utility Solutions

Feeder or Group of Machines

Where is the best solution?

105

Some significant international benchmarking efforts

DPQ Project - USA– 300 sites, 24 utilities, 2 years of

monitoring

UNIPEDE Benchmarking Project -Europe– 85 substation sites, European utilities, 1

year of monitoring

Benchmarking for development of NRS 048 Standard - South Africa– 200 sites 2 years of monitoring

Utility participantsBoone Electric CooperativeChattanooga Power BoardCincinnati Gas & Electric CompanyDelmarva Power & Light CompanyDuke Power CompanyEast Kentucky Power CooperativeElizabethan Electric SystemEmpire District Electric CompanyFlorida Power CorporationGeorgia Power CompanyGibson County Electric MembershipHouston Lighting & PowerIllinois Power Company Kansas City Power & Light CompanyLong Island Lighting CompanyLos Angeles Department Of Water & PowerMassachusetts Electric CompanyNortheast Utilities ServicePacific Gas & Electric CompanyPublic Service Electric & Gas CompanyRochester Gas & Electric CorporationSierra Pacific CompanySnohomish Public Utility District #1Western Resources

Multi-phase, multi-year projectwhich involved 24 EPRI member utilities.

106

Voltage sags

Focus now on voltage sags because these are the most important power quality variations affecting industrial customers.

DPQ voltage sag performance

Average Yearly Rate Substations Only

Feeders Only

Feeder Average

Interruptions V<10% 3.65 5.08 4.58Sags 10%<V<90% 43.60 46.22 45.31Sags and Interruptions 47.25 51.30 49.90

Note: these results arebased on the minimumvoltage and one minuteaggregation.

Sag and Interruption Rate Magnitude Histogram

0.00

0.25

0.50

0.75

1.00

1.25

0 to

5

5 to

10

10 to

15

15 to

20

20 to

25

25 to

30

30 to

35

35 to

40

40 to

45

45 to

50

50 to

55

55 to

60

60 to

65

65 to

70

70 to

75

75 to

80

80 to

85

85 to

90

RMS Voltage Magnitude (%)

Sags

and

Inte

rrup

tions

per

Site

pe

r 30

Day

s

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Cum

ulat

ive

Freq

uenc

ySag and Interruption RateCumulative Frequency

All Sites, One-Minute Aggregate Window

107

UNIPEDE benchmarking results -EuropeCable Systems

Mixed Systems

Summary comparison of major benchmarking projects

SARFI – System average rms frequency indexSARFI-70 – The expected annual number of

voltage sags with a retained voltage of less than 70% of nominal

108

Categories of system voltage sag performance

Category 1 - Best Systems or Systems with Low Fault Exposure– SARFI-70 less than 10– SARFI-90 less than 30

Category 2 - Typical or Average Systems– SARFI-70 between 10 and 30– SARFI-90 between 30 and 100

Category 3 - Rural Systems or Systems with High Fault Exposure– SARFI-70 greater than 30– SARFI-90 greater than 100

Using simulations to study performance

109

Newman

Blackwater

West MesaB-A

NortonLos Alamos

Ojo

Santa Fe

Albuquerque

Roswell

Las CrucesDeming

Clovis

Arroyo

Sandia

Luna

FarmingtonFour Corners

Gallup AmbrosiaPlains (PGT) Tap

345kV230kV

Area of vulnerability<90% voltage retained

345kV230kV

West MesaB-A

NortonLos Alamos

Santa Fe

Albuquerque

Roswell

Las CrucesDeming

ClovisSandia

FarmingtonFour Corners

Gallup

Area of vulnerability<70% voltage retained

110

Expected annual voltage sag profile

Voltage Sags(Percent Normal Voltage)

Events Per

Year

0

5

10

15

20

25

30

35

40

<50% <60% <70% <80% <85% <90%

46kV

115kV

230kV

345kV

1.85.0

10.315.2

23.3

33.9Fault

Location

Voltage Class Median Performance (Faults/100mi/year)

345/500kV 1.8 230kV 4.0 115/138kV 6.5 46/69kV 18

Key parameter – transmission line fault performance

111

Panel Session PN13Non-periodic Currents:

Causes, Effects and Identification

Interharmonics in Power Systems

Interharmonics in Power Systems

DefinitionStandardsSourcesImpactsSolutions

112

Interharmonics -Definition

IEC-61000-2-1 defines Interharmonics as:

“Between the harmonics of the power frequency voltage and current, further frequencies can be observed which are not an integer of the fundamental. They can appear as discrete frequencies or as a wide-band spectrum”

Standards and Working Groups

IEC 61000-4-7 - MeasurementsIEEE Task Force on InterharmonicsIEEE 519 - under revision - adds interharmonicsCigre 36.05 - Voltage Quality Working Group

113

IEC Harmonic / InterharmonicMeasurement Standard: IEC 61000-4-7

Number of cycles to sample chosen to provide 5 Hz frequency bins– 10 Cycles for 50 Hz Systems– 12 Cycles for 60 Hz Systems

Grouping concept– Harmonic factors calculated as the square root of the sum of

the squares of the harmonic bin and two adjacent bins.– Interharmonic factors calculated as the square root of the

sum of the squares of the bins in between the harmonic bins (not including the bins directly adjacent to the harmonic bin).

Frequency Bin Grouping

114

Frequency Bin Grouping

Interharmonic Sources

Arc furnaces CycloconvertersPower line carrier communicationsPWM power electronic systemsInteraction of controls and power system components

115

Example Case Where dc Arc Furnace Caused Unacceptable Flicker Levels

Converter control problems result in increased interharmonic generationSystem resonance magnifies the interharmonic component (186 Hertz)Result is 6 Hertz modulation that causes light flicker over a wide area

Example System One Line Diagram for Harmonic and Flicker Evaluations

Customer

Customer

116

Frequency Response with Initial Filter Design

0 200 400 600 800 0

25

50

75

100

125

150

Frequency (Hz)

Driving Point Impedance (Ohm)

186 hertz

Voltage at the 26 kV Bus

117

Current at the 26 kV Bus

Effect of the Rolling MillModern rolling mills will typically use cycloconverters. They also generate significant interharmonic components.Example waveform and spectrum used for design purposes:CASE41>S35K3A-FEED3A(Type 9)

270 280 290 300-2000

-1000

0

1000

2000

Time (mS)

Current (A)

Max:Min:Avg:Abs:RMS:CF :FF :

1536.08 -1498.02 821.937 1536.08 940.961 1.63245 1.14481

DERIVED>S35K3A-FEED3A(Type 9)

0 6 12 18 24 0

10

20

30

40

Frequency (Hz pu)

Current (A)

Freq :Fund :THD :TID :TD :RMSh :RMSi :RMSfh:RMS :ASUM :TIF :IT :

1 966.448 6.40455 0 6.40455 61.8967 0 968.428 968.428 1349.88 146.679 142048

118

Impacts

Similar to impact of harmonic distortion– Heating– Altered/multiple zero crossing– Telecommunications interference

Unique impacts– Light flicker– Torsional oscillation excitation

Light Flicker due to Interharmonics

119

SolutionsFix control problems to reduce level of interharmonic generation.Non-characteristic harmonics and interharmonics must be considered in the filter design for dc arc furnaces and other interharmonic producing loads.Resonances created by the filters in parallel with the system inductance can magnify interharmonic components causing high distortion and flicker.Damping should be included in filter designs to avoid interharmonic problems.

Conclusions

Interharmonics have always been around, they are just becoming more important and visible.Power electronic advances are resulting in increasing levels of interharmonic distortion.Traditional filter designs can result in resonances that make interharmonic problems worse.Light flicker is the most common impact.Measurement is difficult, but standards make them possible and the results comparable.

120

Procedimentos para Campanhas de Medição de Indicadores de

QEE e Ensaios de Instrumento de Medição

239

MÉTODO DE AVALIAÇÃO UFU

Nenhum instrumento recebeu apenas conceitos B/E nos módulos;

Apenas 1 instrumento apresentou todos conceitos R/I nos módulos;

Cinco instrumentos apresentaram apenas 1 conceito R/I nos cinco módulos;

Constatações Quanto aos Resultados da Avaliação

121

MÉTODO DE AVALIAÇÃO UFU

Número de instrumentos com conceitos B/E nos vários módulos:• Harmônica: 12• Desequilíbrio: 7• Flutuação: 3• VTCD: 9• Veficaz: 20

Número de instrumentos com conceitos B/I nos vários módulos:• Harmônica: 9• Desequilíbrio: 14• Flutuação: 18• VTCD: 12• Veficaz: 1

Constatações Quanto aos Resultados da Avaliação

MÉTODO DE AVALIAÇÃO UFU

Combinando-se módulos de VTCD e Veficaz (avaliação via SMF), resulta o seguinte número de instrumentos com conceito B/E:• VTCD / Vef: 9

Combinando-se os módulos de Harmônicas, Desequilíbrio e Flutuação (avaliação via campanha), resulta os seguintes números de instrumentos com conceitos B/E:• H / D / F: 1• H / D: 5• H / F: 3• D / F: 1

Constatações Quanto aos Resultados da Avaliação

122

MÉTODO DE AVALIAÇÃO PROF. PAULO RIBEIRO

Critérios Utilizados na Avaliação (Preliminar):

• Eliminação Simples (incluindo todos os testes)O instrumento será aprovado caso apresente em todos os testes do módulo erro inferior ou igual a 10% (o valor de 10% procura para acomodar inúmeras condições de imprecisão, variações nos proticolos de medicao, etc. ).

• Média Notas Desempenho (baseado critério UFU)O instrumento será aprovado caso obtenha desempenho médio no módulo considerado B ou E.

Constatações Quanto aos Resultados da Avaliação

MÉTODO DE AVALIAÇÃO PROF. PAULO RIBEIRO

Critérios Utilizados na Avaliação (Preliminar):

• Eliminação Simples (regime permanente)Nesta avaliação adotou-se o mesmo critério de 10%, contudo não foram considerados, por módulo de testes, as variações abruptas dos sinais, bem como sinais compostospor mais de uma perturbação. Apenas foram incluídas as avaliações de distorção harmônica, flutuação e desequilíbrio.

• Eliminação Simples (sem variações de freqüência)Nesta avaliação, além do critério anterior, não foram considerados os testes com freqüência diferente de 60 Hz.

Constatações Quanto aos Resultados da Avaliação

123

Eliminacao Simples (incluindo todos os testes)

A, B, C, D, E, F, G, H, I, L, M, N, O, P, Q, R, S, T,U, V

Variacao de Tensao em Regime PermaneneteEnsaios 67-74

QVariacao de Tensao de Curta Duracao (Voltage Sags)Ensaios 35-66

BFlutuacao de Tensao (Flicker)Ensaios 29-34

-Desequilibrio de TensaoEnsaios 22-28

-Tensoes HarmonicasEnsaios 01 - 21

Instrumento que satisfizeram o critério de erro relativo igual ou menor que 10%

Grandeza Medida

Media de Notas de Desempenho(baseado no Criterio UFU – B/E)

A, B, C, D, E, F, G, H, I, L, M, N, O, P, Q, R, S, T,U, V

Variacao de Tensaoem Regime PermaneneteEnsaios 67-74

C, D, F, G, J, L, M, N, O, Q, T, UVariacao de Tensaode Curta Duracao(Voltage Sags)Ensaios 35-66

B, Q, NFlutuacao de Tensao(Flicker)Ensaios 29-34

A, B, D, G, H, O, VDesequilibrio de TensaoEnsaios 22-28

A, B, C, D, F, G, L, M, N, O, Q, UTensoes HarmonicasEnsaios 01 - 21

Instrumento que satisfizeram o criterioGrandeza Medida

124

B, Q, NFlutuacao de Tensao (Flicker)Ensaios 29-34

B, D, G, H, O, VDesequilibrio de TensaoEnsaios 22-28

B, C, D, G, M, O, QTensoesHarmonicasEnsaios 01 - 21

Instrumento que satisfizeram o critério de erro relativo igual ou menor que 10% (regime permanente)

Grandeza Medida

Eliminacao Simples (Regime Permanente)

Eliminacao Simples(Sem Variações de Frequencia)

B, Q, NFlutuacao de Tensao(Flicker)Ensaios 29-34

A, B, D, G, H, O, VDesequilibrio de TensaoEnsaios 22-28

A, B, C, D, F, G, L, M, O, Q, UTensoes HarmonicasEnsaios 01 - 21

Instrumento que satisfizeram o critério de erro relativo igual ou menor que 10%

Grandeza Medida

125

Eliminacao Simples (incluindo todos os testes)

Número de instrumentos aprovados

20

1

1

0

0

Todos os testes

20

12

3

7

12

Criterio UFU

--

--

3

6

7

Regime

--Variacao de Tensao em Regime PermaneneteEnsaios 67-74

--Variacao de Tensao de Curta Duracao (Voltage Sags)Ensaios 35-66

3Flutuacao de Tensao (Flicker)Ensaios 29-34

7Desequilibrio de TensaoEnsaios 22-28

11Tensoes HarmonicasEnsaios 01 - 21

S/ Frequencia

Grandeza Medida

MÉTODO DE AVALIAÇÃO PROF. PAULO RIBEIRO

Baseado na Eliminacao Simples (regime permanente, sem variacoes de frequencia e sem variacoes abruptas e desequilibrios para testes 01 a 28):

Instrumentos Selecionados (Selecao Preliminar):

Harmonicos: B, C, D, G, M, O, Q

Desequilibrio de Tensao: B, D, G, H, O, V

Flutuacao de Tensao: B, Q, N

Em caso de medicoes com significantes variacoes rapidas no tempo, desequilbrio, etc., medicoes adicionais devem ser realizadas.

Contatar fabricantes de instrumentos que ultrapassaram criterios e realizar novostestes quando novos protocolos forem implementados.

Proposta preliminar e RecomendaçõesQuanto a seleção de instrumentos

126

Proposta preliminar e RecomendaçõesQuanto a seleção de instrumentos

MÉTODO DE AVALIAÇÃO PROF. PAULO RIBEIRO

Os ensaios de laboratório realizados foram capazes de proporcionar uma comparacao precisa (com relacao a valorespadroes de desvios da tensao) e relativa entre os diversosinstrumentos testados de forma a selecionar os equipamentostestados segundo o seu desempenho. Tal seleção permite inferirque os instrumentos classificados como aceitaveis/adequados, deverão apresentar melhores resultados em situações de campo.

Adicionalmente, os equipamentos de um mesmo grupo deverãoapresentar resultados de mesma qualidade, desde quesubmetidos a sinais com grau de perturbação semelhante aostestados.

Proposta preliminar e RecomendaçõesQuanto a seleção de instrumentos

MÉTODO DE AVALIAÇÃO PROF. PAULO RIBEIROConsiderando as condições que normalmente se apresentam emsistemas de transmissão, considera-se que os equipamentosconsiderados adequados na avaliação do tipo Avaliação Simples (regime permanente) devem satisfazer as necessidades de acompanhamento dos niveis de qualidade na rede basica. A excessão ocorre em pontos de medição que apresentem forte desequilíbrio ou que estejam suprindo cargas que apresentemvariações abruptas importantes. Nesta situação, considerandoque os equipamentos não responderam de forma conveniente, deve-se buscar uma evolução tanto nos testes de avaliação, emlaboratório e em campo, como uma melhoria nos protocolos de medição utilizados pelos instrumentos de forma a avaliar taissituações.

127

MÉTODO DE AVALIAÇÃO PROF. PAULO RIBEIROFinalmente, recomendamos ao ONS continuar esse projeto de afericao dos instrumentos de qualidade de energia ao mesmo tempo que deve acompanhar os desenvolvimentos nos orgaostecnicos internacionais para estabelecimento de protocolos de medicao.

Os resultados obtidos nesse projeto tem um potencial significante de influenciar tanto os orgaos tecnicos internacionais como os fabricantes de instrumentos no sentido de deteminar a compatibilidade de procedimentos e protocolos que facilitem o processo de genrenciamento da qualidade de energia .

Proposta preliminar e RecomendaçõesQuanto a seleção de instrumentos

Gerenciamento da Qualidade de Energia Elétrica

- Breve Introdução

- Consumidores na Transmissão / Distribuição

- Interface Transmissão / Distribuição

- Programas de Qualidade de Energia

- Aspectos Econômicos / Custos

- Contratos / Seguros de Qualidade

- Planejamento da Distribuição

128

Gerenciamento da Qualidade de Energia Elétrica- Breve Introdução

- Consumidores na Transmissão / Distribuição

- Interface Transmissão / Distribuição

Gerenciamento da Qualidade de Energia Elétrica

- Programas de Qualidade de Energia

- Aspectos Econômicos / Custos

- Contratos / Seguros de Qualidade

- Planejamento da Distribuição

129

Programas de Qualidade de Energia

ViolaçãoReportada

Obter Dados Detalhados, Caracterizar Fenômeno

Modelar Simular, Analisar

SistemaAvaliar Desempenho

InvestigarSoluções

Alternativas

Executar Solução

AvaliarSolução

MonitoraçãoVh, V2, ∆V

Determinar Responsabilidades

SatisfazParâmetros deDesempenho?

Objetivo:Operação Ótima

sim

OperaçãoÓtima

Parâmetros deDesempenhoVh, V2, ∆V

Resolver Aspectos Legais

Especificar Solução

Determinar Impacto Econômico

ViolaçãoSeria?

sim

não

Acompanhar

Performance Indices

MonitorMeasure

StudySimulate

CompareWith

IndicesSatisfactory

Possible SolutionsResponsibility

Assessment

Implementing Solutions

Reporting

VerificationEnforcement

FutureSystem/Agents

ExistingSystem/Agents

EducationInformation

PQ Program

Unsatisfactory

130

Why is a PQ Program Needed?

Power quality characteristics on the transmission system are a very important component of the overall power quality delivered to the end user, whether the end user is supplied directly from the transmission system or from a distribution company. A few specific examples of concerns are listed here:

Harmonic distortion on the transmission system can excite local resonances on the distribution system or within customer facilities, causing excessive voltage distortion at lower voltages. This can result in equipment failures (transformers, motors, capacitor banks) and interference problems. Coordinated solutions are required.Voltage fluctuations on the transmission system can propagate down to lower voltages resulted in light flicker for large numbers of customers. This can be very annoying and many customers may complain of these conditions.

Why is a PQ Program Needed?

Capacitor switching operations on the transmission system (not currently a problem in Brasil) can cause transient voltages that get magnified at lower voltages, resulting in equipment misoperation and even failures. Specific requirements for capacitor switching have been implemented in England and by many transmission companies.Voltage sags are caused by faults on the transmission system, as well as faults on distribution systems. Many times, 50% or more of the voltage sags that cause problems for industrial customers are associated with faults at the transmission level. Fault performance and the resulting voltage sags should be evaluated on an ongoing basis and an objective of continuous improvement in performance should be established, similar to the objectives for reliability improvement at the distribution level. Customers require information about the expected performance in order to optimize the design of their facilities and evaluate the economics of power conditioning systemsUnbalanced voltages or harmonic distortion on the transmission system can cause excessive heating in generators, resulting in tripping of the generators. Flicker can also be a concern for generators due to low frequency resonances that can result in torque oscillations that damage the turbine.

131

Specific Functions of the PQMS

Important functions of the PQMS include the following:Benchmarking the system performance (expected power quality levels). This may involve a combination of monitoring of system power quality levels over time and analysis of expected power quality levels using simulation tools.Assessing the actual performance with respect to established benchmarks, compatibility levels, system performance guidelines, and planning levels. This will primarily be a function of the monitoring system.Managing the database of transmission power quality performance information. The monitoring system database is the resource that will be used to assess ongoing performance, identify power quality trends, identify possible problem areas, and provide performance information for distribution companies and end users.Reporting on transmission power quality levels and concerns. Standard reports of system performance with respect to guidelines should be provided. Problem areas should be identified specifically for resolution.

Specific Functions of the PQMS

Developing recommended solutions for improving performance where there are problem conditions. The PQMS should incorporate the tools for evaluating the causes of problem conditions and should be used to develop recommended solutions to improve performance. This function of the PQMS will involve analysis and simulation tools that work in conjunction with the monitoring systems. This function of the PQMS will involve assigning responsibilities for improving performance at various levels of the system (transmission operators, distribution companies, end users, generators).Planning for new loads, distribution system connections, generators, andtransmission system changes. All changes to the transmission system infrastructure can impact the power quality levels. The PQMS should support evaluation of prospective changes and new connections to assure that they will not result in power quality problems. This is especially important for connections that can result in increased flicker or harmonic levels.Educating the various agents impacted by transmission power quality. Reporting functions of the PQMS should be used to educate the generators, distribution companies, and end users about power quality levels and their respective responsibilities in maintaining compatibility of the overall system.

132

D/A

Tested hardware

Simulator (computer)

A/D

Inputs tohardware

Outputs fromhardware

Outputs from simulatorsInputs to simulators

An Advanced Power Quality AssessmentUsing RT-HIL Approach

The Need for Integrated Laboratories and Research Centers

Example

Firing pulseboard

Power grid6-pulse

thyristor rectifier

YYVL-L=12.47 kV

Lline=0.05 p.u.Rline=0.005 p.u. LT=0.05 p.u.

RT=0.005 p.u.

Distribution transformer12.47 kV/480 V

IndustryDC load

-

+

RL=0.48 ohmLL=1 mH

PQ phenomena Simulation results

THD • Tolerate THD up to 14.8% and higher • Tolerance has no impact on distribution systems

Voltage sag • Tolerance depends on not only the time duration and voltage reduction, but also phase shift • Tolerance results in DC voltage drop or blackout

Frequency change • Tolerate system frequency from 30 Hz to 80 Hz

An Advanced Power Quality AssessmentUsing RT-HIL ApproachExample

133

Debates – Mesa Redonda

Power Quality Evolving Environment

How To Interpret This?

134

Power Quality Evolving Environment

How To Interpret This?

135

No definite indices

Indices short-time

95%95%95%Indices

Shipboard

Transmission Supply voltage characteristics

Supply voltage characteristics

Planning levels for controlling emissions

Supply voltage characteristics

Minimum standard used by the regulator

Planning Levels

PQ measurement methods

Emissions and Supply Voltage

Supply Voltage

Purpose

USABrazilQuebecEnglandFranceSouth Africa

International

International

USA and other countries

19 European Countries

Where

Military Standard

National Standard

VoluntaryNational Standard

Premium Power

National Standard

Technical Report

Technical Report

ANSI Standard; Recommended Practice

European Standard

Status

MIL Std 1399-300A

ONS -Brazil

HQ Voltage Charact

ER G5/4EDF Emerald Contract

NRS048-2 :96

IEC 61000-3-6 :1996

IEC 61000-4-30

IEEE-519

EN50160:2000

Standard

330 20 20 20 50 321

330.20.20.20.50.3820

331.21.51.21.51.7619

330.20.20.20.50.3918

331.621.62217

330.20.20.20.50.4116

330.30.30.30.50.415

330.20.20.20.50.4314

332.532.53313

330.20.20.40.50.4612

3333.533.53.511

330.40.50.40.50.510

331.21.51.21.51.59

330.40.50.40.50.58

33454557

330.50.50.50.50.56

33564665

33111114

33454553

331.621.6222

MIL 1399IEEE 519

IEC 61000-3-6

NRS 048-2ER G5/4EN50160IEC 61000-4-30Order

136

Proposed Voltage Harmonic Limits For Shipboard Systems

0.521

0.520

319

0.518

317

0.516

0.515

0.514

413

0.512

411

110

19

18

57

16

55

14

53

22

Recommended LimitsEven Odd TripleOrder

Proposed Voltage Harmonic Limits For Shipboard Systems

Recommended Action - > 9%Possible Problems – 7 - 9%THDCaution – 5 - 7%

1>25

225

0.524

223

0.522

Recommended LimitsEven Odd TripleOrder

137

5 10 15 20 250

2

4

6

Harmonic Voltages

Har

mon

ic O

rder

7

0

Veveni

Vtriplei

Voddi

IEEE519i

271 i

Proposed Voltage Harmonic Limits For Shipboard Systems

IEEE 519 Vh Limits (odd components) Limits

0 5 10 15 20 250

5

10

15

20

Time (Minutes)

Vol

tage

TH

D (%

)

20

0

THDProblems2i

THDCaution2i

THDShortTermi

IEEE519THDi

251 i

IEEE 519 THD Limit

Proposed Short-Term Limits

Proposed Max 95% THD Limit

Proposed Voltage Harmonic Limits For Shipboard Systems

138

0 0.01 0.02 0.03 0.04 0.052

1

0

1

21.25

1.25−

y1 t( )

y2 t( )

y3 t( )

y11 t( )

0.050 t

Upper Boundary

Lower Boundary

Zero Crossing Restrictions

Peak Variation

Waveform Distortion Limitation: An Alternative ApproachVia Envelop Boundaries

139

Generation Delivery Conversion Processing

CentralStation

T&D AC-ACSupplies

Motion

EnvironmentalMaintainability

AvailabilitySafety

EfficiencyReliability

PerformancePrice

Power Quality

Power System Value Chain

Power Electronics Systems and Components

SMESBatteries

FACTSSMESPQ Parks

UPS Appliances

INPUTS OUTPUTS

Valu

e Di

men

sions

Energy Power Communication

Light / Motion

Utility User

The Integrated Quality Environment

140

Technology Transmission Line Transfer Enhancement

Cost Range Operating principle Procurement Availability

Reconductor lines Increase thermal capacity $50K to $200K per mile

Increases thermal limit for line Competitive

Fixed or Switched Shunt Reactors

Voltage reduction – Light Load Management

$8-$12 kVAR Compensates for capacitive var-load

Competitive

Fixed or Switched Shunt Capacitors

Voltage support and stability

$8-$10 kVAR Compensates for inductive var-load

Competitive

Fixed or Switched Series Capacitors

Power flow control, Voltage support and Stability

$12-$16 kVAR Reduces inductive line impedance

Competitive

Static VAR Compensators Voltage support and stability

$20-$45 kVAR Compensates for inductive and/or capacitive var-load

Competitive

Thyristor Controlled Series Compensation (TCSC)

Power flow control, Voltage support and stability

$25-$50 kVAR Reduces or increases inductive line impedance

Limited competition

STATCOM Voltage support and stability

$80-$100 kVAR Compensates for inductive and capacitive var-load

Limited competition

STATCOM w/SMES Voltage support and stability

$150-$300 kW Compensates for inductive and/or capacitive var-load plus energy storage for active power

Limited

Unified Power Flow Controller (UPFC)

Power flow control, Voltage support, and Stability

$150-$200 kW SVC and TCSC functions plus phase angle control

Sole source

Unified Power Flow Controller (UPFC) w/SMES

Power flow control Voltage support and Stability,

$250-$350 kW SVC and TCSC functions plus voltage regulator, phase angle controller and energy storage

Sole source

Shaded area indicates technologies that are either permanently connected or switched on or off with mechanical switches. (i.e. these are not continuously controllable)

Cost Considerations

Summary Comparison of DG Technologies

On grid windfarms, off-grid telecom, instruments and other sites

700-1,200

Not configured for this capabilityNA0.2 kW up

to 5 MWWind

Turbines

Residential offgrid, net metered residential on-grid, green power, offgrid telecom and

instruments

4,000-6,500

Not normally configured for this capability – some products are available

NA1 W up to 10 MWPhotovoltaics

Industrial/commercial facilities, critical power, low emissions niche markets

4,000-50,000

Good potential for cogeneration (can be up to

90% efficient)35-60%<1 kW up to 10 MWFuel Cells

Small commercial and industrial applications

700-1,000

Good potential for cogeneration (can be up to

90% efficient)22–30%27-400 kWMicroturbine

Industrial/commercial facilities application/islanded power plants/standby

power300-900

Good potential for cogeneration (can be up to

90% efficient)25-38%1 kW up to

10 MW IC Engine

Industrial facilities/small utility peaking plants

500-1,000

Good potential for cogeneration (can be up to

90% efficient)25-40%1-50 MW

Industrial Combustion

Turbines

large utility owned central station power plants400-500

Not normally an application with this type of plant but

could be done50-60%50-500 MW

Combustion Turbine

CombiinedCycle

Common Applications

Current Installed

Cost($/kW)

Viability and Efficiency In Cogeneration Application

Electrical Efficiency (%LHV)

Applied Size Range

Generation Technology

141

Modeling of Linear Components for Harmonic Studies

Paulo F. Ribeiro

Task Force on Harmonic Modeling and Simulation

IEEE Transactions on Power Delivery, PRD 18-2, April 2003, pp. 625-30

Impact of Aggregated Linear Load Modeling on Harmonic

Analysis:A Comparison of Common Practice and

Analytical Models

Task Force on Harmonic Modeling and Simulation

IEEE Transactions on Power Delivery, PRD 18-2, April 2003, pp. 625-30.

142

Outline

Introduction: Linear and Non-Linear Loads

Survey of Linear Load Models– Mostly resistive loads– Loads with significant Induction Motor participation– Treatment of network elements

Comprehensive Load Models– Inclusion of electronic and other harmonic loads– Inclusion of background distortion– Reactive power compensation elements

Sensitivity Studies

Load Model Classification

Apparatus

Non-LinearHarmonic Producing

(ASD’s, Arc Furnace, Electronics, etc)

LinearNot Producing Harmonics

(Impedance representation)

Resistive Motors(Other than ASD’s)

143

Sample Load Composition

Linear (Resistive)Non-linearLinear (Resistive)Linear (Motor)

Non-linearNon-linearLinear (Motor)

Linear (Motor)Non-linearLinear (Motor)Non-linear

Domestic• Incandescent lamps • Home electronics • Resistive heater• Air conditioningCommercial• Fluorescent lamps• Computers• Air conditioningIndustrial• Motors• ASD’s• Pumps• Arc Furnace

Electrical CharacteristicsType of Load

Description of Linear Loads

Aggregate Real and Reactive Power (P and Q) corresponding to the Linear Load:– Precise impedance representation at

fundamental frequency– Imprecise motor impedance representation at

harmonic frequencies

Motor Participation:– K, the fraction of motor load on a bus:

Fraction of Motor Load: KFraction of Resistive Load: 1-K

PPK M=

144

Model Complexity vs. the K-Factor

Low Motor Participation (K<0.1):– Mostly resistive load– Simple series or Parallel RL models– Obtain model parameters from P and Q

Significant Motor Participation:– Damping at harmonic frequencies– Obtain model parameters from P and Q,

and typical motor characteristics

Mostly Resistive Loads (K<0.1)

Series RL

R

jhX

22

2

22

2

QPVQX

QPVPR

+⋅=

+⋅=

145

…Case K<0.1

Parallel RL

R jhX

QVX

PVR

2

2

=

=

…Case K<0.1

Inclusion of Skin Effect

R(h) jhX(h)

9.01.0)(

)()(

)()(

2

2

+⋅=

⋅=

⋅=

hhm

QhmVhX

PhmVhR

146

Significant Motor Participation

Treat Resistive and Motor Loads separately:1) Resistive load: (1-K)P2) Motor load: KP

• Additional Motor InformationQuality factor K3=X/RPU Locked rotor reactance XM

Install factor Km=1/(power factor)

…Significant Motor Load

Simple Parallel Model

R2 jhX1

Resistive Motive

PKKVXX

PKVR

mM ⋅⋅

⋅=

⋅−=

2

1

2

2 )1(

147

…Significant Motor LoadCIGRE-EDF Model

PQ

PKVX

RX

PKVR

=

−⋅⋅⋅=

⋅=

⋅−=

φ

φ

tan

)74.0tan7.6(

073.0

)1(

2

1

22

22

R2

jhX2jhX1

Resistive Motive

…Case with K>0.7

Inclusion of Damping

R1

jhX1

R2

jhX2

Resistive Motive

311

22 1.0KXRRX

=⋅=

PKKVXX

PKVR

mM ⋅⋅

⋅=

⋅−=

2

1

2

2 )1(

Skin Effect:R1,skin(h)=R1(1+0.05(hfo)0.5), X1,skin(h)=2X1(hfo)0.15

148

Network Elements

Power Lines and Cables– Thevenin Source, PI-sections, FDE– Detail representation at the points of

interest

Transformer Representation– Series RL, Skin Effect

PFC Capacitors

Comprehensive Load Representation

Electronically Controlled Load– Harmonic source

Background Distortion– Thevenin source at harmonic

frequencies

Reactive Power Compensation, PFC

149

Comprehensive Load Model

Electronic Load: KE

Motor Load: K

Resistive Load: 1-K-KE

e.g. Ih=I1/h

Sensitivity Studies

Load Composition

Reactive Power Compensation

Background Distortion

150

System Studied

0.001Ω

0.0107H

11 kVSystemSource

HarmonicSource

Load

PFC

Harmonic Source (A):I5 = 0.840I7 = 0.601I11=0.382I13=0.323

Linear Load: 743 kW

PFC: 741 kVAR

Varying Load Composition

2 4 6 8 10 12 14 16 18 2010

1

102

103

Frequency (x60Hz)

Impe

danc

e (O

hm)

7

8

9

Case 7: K=0.25Case 8: K=0.75Case 9: K=0.90

020406080

100120

7 8 9

Case #

Volta

ge (V

) 5th7th11th13th

151

Adjusting PFC

1. Vary Load CompositionK=0.25,0.75,0.90

2. Adjust PFC for Full CompensationMotor power factor: cosφM=0.83Motor reactive consumption:QM=QPFC=KPtanφM

Adjusted PFC

2 4 6 8 10 12 14 16 18 2010

0

101

102

103

Frequency (x60Hz)

Impe

danc

e (O

hm)

10 11

12

0

20

40

60

80

10 11 12

Case #

Volta

ge (V

) 5th7th11th13th

Case 10: K=0.25Case 11: K=0.75Case 12: K=0.90

152

Background Distortion

A 0.5% distortion at 5th, 7th, and 11th.

020406080

100120

16 17 18

Case #

Volta

ge (V

) 5th7th11th13th

Case 16: K=0.25 Case 17: K=0.75 Case 18: K=0.90

Conclusions

P and Q are Inadequate for Harmonic Studies.

Load Composition affects Damping and resonance frequency of harmonic impedance.

Background distortion can interact with a local harmonic source.

153

ConclusionsPQ will continue to grow in importance as the electric sector

operates within a truly free economy.

Utilities, customers and manufacturers will have to cooperate toestablish a stable model for the power quality industry sector

An integrated Approach Is EssentialVision, Philosophy/Strategy and Initiative

Initiatives:Grupos de QE ou Compatibilidade Eletromagnética (GCEM)

Promoção de Uma Visão IntegradaContinuem o excelente trabalho:

Cooperação: Consumidores, Concessionárias, Industria,Outros centros.

"No man who values originality will ever be original. But try to tell the truth as you see it, try to do any bit of work as well as it can be done for the work's sake, and what men call originality will come unsought.“

C.S. Lewis

154

Preperar declaração conjunta.

O instrutor e participantes do Curso Avancado de Qualidade de Energia Eletrica realizado …. PUCRS …… durante o period de …… apos intensos debates e avaliacoes sobre os possiveis impactos dessa qualidade no desempenho da rede eletrica concluiem que:-o setor eletrico acompanha de perto os desenvolvimentos a niveis internacionais…- investimentos adicionais precisam ser ……- pesquisas e desenvolvimentos ….----