sharing apic collaborative research results and experiencesapic/uploads/forum/speakers...

Wednesday, November 5, 2014

Sharing APIC Collaborative Research Results and Experiences

Alberta Power Industry Consortium http://www.ece.ualberta.ca/~apic/

October 15, 2014

Dear Delegates;

The Alberta Power Industry Consortium (APIC) is pleased to welcome you to our 7th Annual Alberta

Power and Energy Innovation Forum, “Sharing APIC Collaborative Research Results and Experiences”.

This year’s forum showcases a number of projects conducted by the University of Alberta in close

collaboration with APIC companies. These projects provide scientific support to the decision making

of APIC companies or introduce technical innovations to help their engineering work. The presenters

also share their collaborative experiences with you so that your department can take advantage of

the opportunities offered by the APIC platform.

We are very pleased to have Mr. Mark F. McGranaghan, Vice-President of Electric Power Research

Institute,( EPRI) US, as a guest speaker to the Forum. Mark will share his thoughts on emerging

technologies and innovations in the utility industry.

I would like to thank the presenters who have generously agreed to share their experience. Also, in

the spirit of collaboration a number of students, ElTs and researchers are also displaying posters of

their research results or project findings. We appreciate your time and contribution to the forum.

Our forum would not be possible without the support of the organizing committee and numerous

volunteers. Many thanks for their good work.

I hope you will enjoy our forum, and look forward to meeting you.

Barrie Gorrie

Chair, Board of Alberta Power Industry Consortium

Director, Distribution Engineering, ATCO Electric

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Table of Contents

About APIC ................................................................................................................................. 1

General Information .................................................................................................................... 2

Forum Location .............................................................................................................................. 2

WiFi Connection ............................................................................................................................ 2

Forum Website .............................................................................................................................. 2

Downloading Forum Materials Online .......................................................................................... 2

Forum Program ........................................................................................................................... 3

Presentations and Speaker Biographies ....................................................................................... 4

Poster Presentations – Industry Engineers in Training ................................................................ 14

Poster Presentations – University of Alberta Researchers ........................................................... 15

Summaries of APIC Project Reports ........................................................................................... 17

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1


About APIC

The Alberta Power Industry Consortium (APIC) consists of six Alberta utility companies,

AESO, AltaLink, ATCO Electric, ENMAX, EPCOR and FortisAlberta, and the University of

Alberta. Established in the fall of 2007, its goal is to bring Alberta power companies

together, with the University of Alberta as the coordinating organization, to solve technical

problems of common interest, to produce more power engineering graduates, to support

the professional development of APIC employees, and to promote technical cooperation

and exchange in Alberta’s power utility companies.

APIC operates under the guidance of an Industry Advisory Board. Current board members

are:

Dan Shield, Director, Transmission Engineering & Performance, AESO

Daniel Wong, Principal Engineer, ALTALINK, L.P. Management Ltd.

Barrie Gorrie, Senior Manager, Distribution Engineering, ATCO Electric Ltd.

Ken Chao, Director, Projects & Engineering, ENMAX Power Corporation.

Suresh Sharma, Director of Transmission, EPCOR Distribution & Transmission Inc.

Richard Bahry, Senior Manager of Distribution Planning, FortisAlberta Inc.

Wilsun Xu, Research Chair Professor, University of Alberta

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General Information

Forum Location

The forum is held in the Solarium, on the 2nd floor of the Engineering Teaching and Learning

Complex (ETLC building) of the University of Alberta, at 9107 - 116 street, Edmonton.

A map of the University of Alberta campus is here: http://www.campusmap.ualberta.ca/

WiFi Connection

A WiFi connection is available courtesy of the University of Alberta.

The connection id is: Guest@UofA. No password is required.

Forum Website

The website of the forum can be accessed at: http://www.ece.ualberta.ca/~apic/

(click on ‘Innovation Forum’ on the left side of the page)

or at: http://www.ece.ualberta.ca/~apic/pmwiki.php?n=Forum.Homepage2014

Downloading Forum Materials Online

Presentations and other forum materials can be downloaded via the forum website.

The password for accessing the materials is: APIC2014UofA

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Forum Program

Time Activity and Speaker

Morning

8:00 – 8:30 Breakfast, registration and poster session

8:30 – 8:40 Welcome and Opening Remarks Wilsun Xu, Professor, University of Alberta

8:40 – 9:10 APIC Activities and Benefits to Industry Partners Barrie Gorrie, Chair, APIC Board and Director, Distribution Engineering, ATCO

9:10 – 9:40 Magnetic Field Emission From Electronic Meters, FortisAlberta Zurex Fontanilla, Senior Engineer, Power Quality Robert Heimann, Manager, Meter Data Management & Technical Services

9:40 – 10:10 Effectiveness of Equipotential Bonding Mats for Hydro-excavation, EPCOR Ray Cislo, Compliance Specialist, Health, Safety & Environment Richard Vercholuk, Trainer, Hydro-Vac U3

10:10 – 10:40 Coffee break and poster session

10:40 – 11:10 Implementation Strategy for Harmonic Monitors in the Calgary Transmission System, ENMAX Samantha Hoffman, Transmission Planning Engineer

11:10 – 11:40 Feeder Neutral Potential Rise Due to GPR Transfer and Induction, ATCO Electric Alexandre Nassif, Senior Engineer, Power Quality & Technical Services

11:40 – 1:00 Lunch and Poster Session U of A researchers will present research work in posters and demonstrations.

Afternoon

1:00 – 1:45 Invited Talk: Emerging Technologies and Innovations for Utility Industry, Electric Power Research Institute (EPRI), United States Mark McGranaghan, Vice-President of EPRI

1:45 – 2:15 Estimation of Fault Resistance from Fault Recording Data, Altalink Daniel Wong, Principal Engineer, Protection & Control Michael Tong, Team Lead, Disturbance Analysis & System Operations

2:15 – 2:45 Coffee break and poster session

2:45 – 3:15 Transmission Line Impedance Estimation Using SCADA Data, AESO James Shen, Principal Engineer, System Operations

3:15 – 3:45 New Methods to Mitigate Power System Harmonics, University of Alberta Wilsun Xu, Professor, University of Alberta

3:45 – 4:00 Closing Remarks and Acknowledgements Barrie Gorrie, Chair, APIC Board and Director, Distribution Engineering, ATCO

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Presentations and Speaker Biographies

1. APIC Activities and Benefits to Industry Partners Barrie Gorrie, Chair, APIC Board and Director, Distribution Engineering, ATCO

Barrie graduated from University of Alberta in 1980. Upon graduation, he went to work with

ATCO Electric where he has held various engineering, operations, and management positions.

Barrie is currently the Director Engineering and Chief Engineer of ATCO Electric - Distribution

Division.

2. Magnetic Field Emission From Electronic Meters, FortisAlberta Zurex Fontanilla, Senior Engineer, Power Quality

Robert Heimann, Manager, Meter Data Management & Technical Services

Zurex Fontanilla is a graduate of Electrical Engineering from the University of Santo Tomas in

the Philippines. Zurex worked for Manila Electric Company (MERALCO) upon graduation and

has over 23 years of technical engineering experience. His work experience includes design

and operation of distribution assets. He currently holds a position with FortisAlberta as Sr.

Engineer, Power Quality. Zurex is a member of CSA Technical Committee C577

Electromagnetic Compatibility, FortisAlberta representative on the Canadian Electricity

Association Power Quality Task Group and a registered professional engineer in the province

of Alberta.

Robert Heimann is a 1985 graduate of Electronics Engineering Technology from the Southern

Alberta Institute of Technology, has a Management Development Certificate from the

University of Alberta and holds a Professional Manager designation from the Canadian

Institute of Management. Robert has 29 years of utility experience related to revenue

metering, implementation of FortisAlberta’s automated metering infrastructure, distribution

equipment refurbishment and ISO quality programs. His metering expertise and leadership

has benefited the metering industry in his role as Chair and participant of various

Measurement Canada working groups related to Federal Metering Policy, as well as the

FortisAlberta management representative on the Canadian Electricity Association Metering

Task Group.

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Notes

Speaker presentations can be accessed online at: http://www.ece.ualberta.ca/~apic/

Click on ‘Innovation Forum’ on the left-hand side of the web-page.

Under ‘Download Forum Materials’, the password is: APIC2014UofA

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3. Effectiveness of Equipotential Bonding Mats for Hydro-excavation, EPCOR Ray Cislo, Compliance Specialist, Health, Safety & Environment

Richard Vercholuk, Trainer, Hydro-Vac U3

Ray Cislo holds degrees in electrical engineering from the University of Toronto and Human

Kinetics from the University of Guelph. Combining technical and human performance

knowledge, Ray has prepared medical and hospital safety standards with CSA, worked as a

clinical engineer with the Royal Alexandra Hospital, and prepared Alberta’s Occupational

Health and Safety Code as a Government of Alberta OHS regulator. For the past 4 years he has

done occupational health and safety work with EPCOR. His present responsibilities as a work

methods advisor means he helps crews develop new practices and refine existing ones.

Helping to critically review the use of portable bonding mats is an example of that work.

Richard Vercholuk is a proud 15-year EPCOR employee with a strong commitment to his work.

For the past ten years, Richard has worked as a both a Hydro-vac operator and a

supervisor/trainer. Richard’s primary responsibilities at EPCOR Technologies support the safe

and efficient operation of a fleet of hydro excavators. His day-to-day responsibilities include

training and supervising hydro-vac operators and swampers, orientating hydro-vac

contractors, supervising worksites, and planning and organizing projects involving hydro-

excavation. Researching safer and more efficient work methods and solutions for every-day

jobs to complex projects is Richard’s passion. He aims to provide his colleagues with the

knowledge and confidence they need to hone their skills as operators and accomplish their

work in a safe and productive manner.

4. Implementation Strategy for Harmonic Monitors in the Calgary

Transmission System, ENMAX Samantha Hoffman, Transmission Planning Engineer

Samantha Hoffman is a 2010 graduate of the Electrical Engineering Honours program at

McGill University. Samantha spent a year as an intern working at ABB’s Corporate Research

Centre in Switzerland and worked for ENMAX Corporation upon graduation. She has over 5

years of technical engineering experience. Her work experience includes programming tools

for a substation simulator, the project management and design of distribution and

transmission substation upgrades, performing power system studies on the Calgary

transmission system and developing transmission projects for execution. She has a special

interest in the development of project staging and constructability assessments of large-scale,

brownfield transmission projects. Samantha currently holds a position with ENMAX Power

Corporation as a Transmission Planning Engineer. She is a registered professional engineer in

the province of Alberta. In her free-time, Samantha can be found hiking, biking and

backpacking in the Rocky Mountains.

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Notes




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5. Feeder Neutral Potential Rise Due to GPR Transfer and Induction, ATCO

Electric Alexandre Nassif, Senior Engineer, Power Quality & Technical Services

Alexandre Nassif received his Ph.D. degree from the University of Alberta in 2009, a degree

obtained under the supervision of Dr. Xu. From 2009 to 2012 he worked as a Transmission

Protection Planner in Hydro One, Toronto, and in 2012 he joined ATCO Electric Distribution as

a Senior Engineer, Power Quality. Alex is a licensed Professional Engineer in the province of

Alberta and a Senior Member of IEEE.

6. Emerging Technologies and Innovations for Utility Industry, Electric Power

Research Institute (EPRI), United States Mark McGranaghan, Vice-President of EPRI

Mark McGranaghan is Vice President of Power Delivery and Utilization for the Electric Power

Research Institute (EPRI). He leads the teams responsible for EPRI's research involving

technologies, systems, and practices for power delivery systems from the generator to the

plug and for the devices and technologies that use the electricity.

From 2003 to 2010, McGranaghan was Director of Research in the Distribution and Smart Grid

areas for EPRI. Priorities during this period were restructuring of the distribution research

program, coordinating EPRI research in the smart grid area with government and industry

efforts, creating the smart grid demonstration initiative, and increasing the technical strength

of the EPRI research team.

Prior to joining EPRI, McGranaghan was Vice President at Electrotek Concepts (1998-2003),

where he helped develop a new business area around power quality and power system

studies into a world leader.

From 1978 to 1988 McGranaghan was a Manager at McGraw-Edison/Cooper Power in

Canonsburg, Pennsylvania. He managed studies for the utility industry and internal studies for

application of McGraw-Edison products (power transformers, circuit breakers, arresters,

distribution switchgear, capacitors) and directed a wide range of power system studies.

McGranaghan has Bachelor of Science, Electrical Engineering and Master of Science, Electrical

Engineering degrees from the University of Pittsburgh. He has taught seminars and workshops

around the world and is very active in standards development and industry activities (IEEE,

CIGRE, IEC). He is a member of the NIST Smart Grid Interoperability Panel Governing Board

and he is the Vice-Chairman of the CIRED U.S. National Committee.

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Notes




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7. Estimation of Fault Resistance from Fault Recording Data, Altalink Daniel Wong, Principal Engineer, Protection & Control

Michael Tong, Team Lead, Disturbance Analysis & System Operations

Daniel Wong received his B.Sc. degree from University of New Brunswick in 1975, and worked

as a Lab Instructor in UNB. From 1976 to 1981, Daniel worked for NB Power in the Distribution

Department. From 1981 to 2000, Daniel worked for TransAlta Utilities. He had held many

key roles in Power System Protection. From 2000 to 2005, Daniel worked for General Electric.

His major accountabilities were: Lead Protection Engineer, Product Line Manager and Asia

Sales Liaison. In June 2005, Daniel joined AltaLink in as the Principal Engineer for Protection &

Control. Daniel has over 39 years of engineering experience in Electric Power Industry. He is a

Professional Engineer in Alberta and New Brunswick, and an IEEE Senior Member. He is also

an Executive Board Member of APIC.

Michael Tong received his B.Sc. degree in Electrical Engineering in 1991, from Shanghai Jiao

Tong University, Shanghai, China. He is currently the Team Lead of the Disturbance Analysis

Group in AltaLink, an electric transmission company serving Alberta, Canada. Michael has

been working in the domain of electric power system for over 20 years, and he is a

Professional Engineer in Alberta.

8. Transmission Line Impedance Estimation Using SCADA Data, AESO James Shen, Principal Engineer, System Operations

James Shen received his M. Sc. degree in Power System Engineering from Shanghai Jiaotong

University, China in 1982, and M. Sc. degree in Electrical Engineering from University of

Saskatchewan in 1988. In 1998 he joined Power Pool of Alberta/AESO and worked at different

departments and now is a principal engineer in Power System Applications of Operations

Systems. His specialties include power system analysis, and design/development of business

solutions and market applications and systems. He worked as an engineer at Enmax for many

years and before moved to Canada he was a university faculty in Shanghai Jiaotong University,

China. He is a registered professional engineer in Alberta and a member of IEEE.

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Notes




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9. New Methods to Mitigate Power System Harmonics, University of Alberta Wilsun Xu, Professor, Department of Electrical and Computer Engineering

Dr. Wilsun Xu received a B.Sc. degree from China in 1982 and a Ph.D. degree from the

University of British Columbia, Vancouver, Canada, in 1989. From 1989 to 1996, he was with

BC Hydro as an Electrical Engineer. He has been with the University of Alberta, Edmonton,

Canada, as a Faculty Member since 1996 and is currently a NSERC/iCORE Research Chair

Professor. His current research interests are power disturbance issues such as power quality

and power disturbance analytics.

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Notes




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Poster Presentations – Industry Engineers in Training

1. EIT Experience of Altalink Sameh Al-Eryani, EIT, AltaLink

Sameh Al-Eryani joined AltaLink in 2011 as a substation equipment engineer EIT in the

Engineering Standards and Support group. In his current role, he develops engineering

standards and equipment specifications and support principal engineers with long term

sparing strategies and new technology evaluations. Sameh obtained his BSc. Degree in

electrical engineering from the University of Calgary in 2011 and is currently pursuing his MSc.

at the University of Calgary on part time basis.

2. EIT Experience of Altalink Chu Cheng, Anas Alhomsi, EIT, AltaLink

Chu Cheng joined AltaLink in 2012 for a 16 month internship. Since she has graduated from

Electrical Engineering at the University of Calgary and has jumped into expanding her

protection and control knowledge and is becoming a valuable asset to the Operational

Engineering team.

Anas Alhomsi joined AltaLink in 2012 for a 16 month internship after completing his third year

of Electrical Engineering with a specialization in Energy and Environment at the University of

Calgary. Since graduation he is working in System Operations and adds value to his team by

preparing outages risk assessments and dealing with real time issues on the system.

3. Overview of Solar Industry in Alberta Michael Chai, EIT, ENMAX

Michael Chai is a 2014 graduate of Energy Systems Engineering from University of Toronto.

Michael worked for Toronto Hydro as an Intern before joining ENMAX Corporation upon

graduation in 2014. His work experience includes Risk-Based Asset Management, Network

Design and Distributed Generation. He has a special interest in the Optimization and Power

Electronics of Renewable Energy Systems. Michael currently holds an EIT position with

ENMAX. Michael is an active member of the IEEE and was the 2013-2014 Chair the IEEE UofT

Student Branch.

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Poster Presentations – University of Alberta Researchers Presenter Title

Alaei, Ramiar A Review on High Power Multilevel Converters

Ding, Tianyu (Tyrone) Micro-filter scheme to mitigate harmonics in residential systems – feasibility research*

Ding, Tianyu (Tyrone) Harmonics in the Alberta power transmission system*

Gao, Pengfei Investigation on EMF emission from electronic meters*

Gao, Pengfei Sensor for telephone interference measurement

Haji Moghimi, Moosa A Survey on Power System Steady-state and Dynamic Equivalents

Li, Benzhe Electrical Signatures of Utility Equipment Failure

Li, Xiang Micro-filter scheme to mitigate harmonics in residential systems – hardware research

Li, Xin (Shawn) Characteristics of Interharmonics Produced by VFDs

Liu, Zhixue (Sam) A Novel circuit-breaker failure protection scheme

Shabestary, Masoud A Comparative Study on Low-Voltage Ride-Through Reference-Current-Generation (LVRT-RCG) Strategies in Converter-Interfaced DG Units

Shabestary, Masoud Maximum Allowable Reactive Power Delivery under Different Grid Faults and Respecting Phase-Currents-Limitation Imposed by DG Owners

Shaloudegi, Kiarash Spectral Learning: Application for Non-Intrusive Home Appliance Monitoring

Wang, Yang (Frank) Fault Resistance Estimation Based on Fault Records*

Wang, Yang (Frank) Transmission Line Impedance Estimation Using SCADA Data*

Wu, Wenriu Real-time Large-scale Matrix Solver in Power Flow Problem Using FPGAs

Xia, Bing (Michael) Feeder Neutral Potential Rise due to GPR Transfer & Induction*

Xia, Bing (Michael) Effectiveness of Equipotential Bonding Mats for Hydro-excavation*

Zhang, Wenhai Circuit Parameters Calculation Based on Damped Sinusoidal Signal & Its Applications

Zhou, Yaxiang (Peter) Novel Resynchronization Strategies for Microgrid

Sun, Yuanyuan (Summer)

Modeling of voltage source inverter based VFD for harmonic analysis

Zhu, Ke Capacitor condition monitoring using coded-energization scheme

Zhu, Ke Method to monitor conditions of substation capacitors

Galvan, Juan Temperature Reduction of Power Transformer Tanks due to Stray Losses

Yong, Jing Inductive coordination between distribution feeders and pipelines

Liang, Hao Plug-in Electric Vehicle Charging Demand Estimation via Queueing Network Analysis

*Posters & demos related to presentations

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Summaries of APIC Project

Reports

University of Alberta

For a copy of those reports, e-mail Dr. Wilsun Xu at: [email protected]

mailto:[email protected]

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Report No. 2014B-1

Modeling of Variable Frequency Drives for

Power System Dynamic Studies

August 2014

Variable Frequency Drives (VFDs) are widely used in various industrial applications and make an

increasingly large portion of total loads in industrial facilities. However, dynamic models of VFDs are

currently not available for power systems dynamic studies.

This report presents two sets of research results on the subject of developing models of VFDs for

power systems dynamic studies. The first set of research results clarifies how a VFD responds to

voltage sags. Voltage sags occur when power systems experience short-circuit faults, which is

typically the starting point of power systems dynamic simulation. This research shows that VFDs will

trip when they experience a relatively large voltage sag (>20% - 30% voltage drop). As a result, there

is no need to include VFDs in dynamic studies in this case. Based on the finding, a simple procedure

to determine if a VFD needs to be included for dynamic studies is proposed and presented in this

report.

The second set of research results presents how to model VFDs when they experience mild voltage

disturbances and are able to ride through. The equivalent dynamic models for motor drive systems

dedicated under such conditions are proposed. These models are created using the linearization

approach and include effects of the drive, the motor, and the control system. Aggregation algorithms

for motor drive systems are also proposed to achieve load equivalence facility wide.

Due to significant different topologies for different types of drives, the mathematical models of the

motor drive systems are different. The equivalent dynamic models are created for the two common

motor drive systems, low voltage VSI drives and medium voltage cascaded inverter drives, with their

induction motor loads in this report. These models are expressed by 7th order transfer functions. Both

voltage dependency and frequency dependency are considered in the models. The equivalent

dynamic models and aggregation algorithms are verified to be accurate by comparing dynamic

responses of the developed models with that of the detailed switching models by case studies. The

dynamic model derivation for other types of motor drive systems can serve as the future work.

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Report No. 2014A-1

Feeder Neutral Potential Rise Due to GPR

Transfer & Induction

June 2014

The neutral potential rise (NPR) of MGN feeders is a safety concern because the

neutral grounding points could be located in public areas. The step voltage around

the neutral grounding point may exceed the safety voltage limitation. There are two

causes for NPR and both are associated with fault situations. The first cause is the

transfer of substation ground potential to the neutral if the feeder neutral is

connected to the substation neutral. The second cause is the induction of voltages

on feed neutral by the fault current. This situation arises when the feeder is not

connected to the substation neutral.

This project has determined the key factors affecting the NPR for both causes and

proposed practical methods to estimate the NPR levels. An intuitive explanation on

the mechanism of NPR is also established. One of the potential applications of the

findings is to determine if a feeder neutral should be connected to the substation

neutral from safety perspective.

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Report No. 2013A-1

Estimation of Fault Resistance from Fault

Record Data

September 2013

This report presents the results of an APIC project on the estimation of fault

resistances. Representative fault resistance values are needed for establishing

proper distance relay settings for transmission line protections. In this project, an

algorithm to estimate the fault resistances from fault data recorded by relays or fault

recorders is developed. The algorithm has been verified through simulation and

experimental studies. More importantly, the algorithm has been applied to determine

the fault resistance values for over 50 short-circuit events experienced by the 130kV

and 230kV lines of Altalink. The results have revealed the general range of fault

resistances in the Altalink system. It was found that the fault resistances are less

than 5 ohm for the majority of events analysed.

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Report No. 2013A-2

Applying Temporary Grounds for

Trip Grounding

September 2013

Trip grounding is the practice of grounding a worksite for the safety of field workers. There are,

however, confusion and challenges with respect to this practice. For example, it is not clear as to

what constitutes an ‘acceptable’ trip grounding point for a worksite, how to ensure a grounding

arrangement performing its intended functions and so on. These concerns are especially true when

temporary grounding rods are used. The objective of this project is to address such concerns, clarify

the issues and recommend solutions for the APIC companies.

The project found that the main function or benefit of trip grounding at a worksite is to increase the

fault current, leading to reliable and faster activation of protective relays or fuses. The benefits of

reducing energized voltage, lowering ground potential rise and limiting equipment damage are very

limited and are often not dependable. The requirement for grounding resistance less than 20~25ohm

has been adopted by many utility companies. However, extensive literature search failed to find

documents or papers that provide scientific justifications for the threshold. It seems that the threshold

is established based on what can be achieved by a 3 meter grounding rods under typical and slightly

optimistic soil resistivity values.

Since the purpose of grounding a worksite is to activate the protection, trip grounding is essentially a

protection coordination issue. The threshold of grounding resistance shall be established according to

the system impedance characteristics, the relay operation characteristics, and proper margin of errors.

Based on the measured grounding resistance data and soil resistivity characteristics collected by this

project, the coordination between trip grounding and existing protection schemes is not dependable.

For example, trip grounding provides a false sense of safety for about 15% worksites or higher. This

work also revealed that increasing fault current to activate protection is just a means, not the goal, of

trip grounding. In fact, increasing fault current is highly undesirable from various safety perspectives

such as arc-flash, step voltage and conductor whipping.

This report also presents some short, medium and long term solutions to the problems faced by the

trip grounding practice. The basic consideration of these solutions is to increase or ensure proper

coordination between grounding and protection.

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Report No. 2012A-1

An Investigation on the Effectiveness of Equipotential Bonding Mat

May 2013

This report provides technical and scientific information that APIC companies may

use to determine work practices and procedures associated with the use of portable

equipotential bonding mats (or simply called “bonding mats” or “mats”). The bonding

mats are used, for example, by utility workers during hydro excavation activities to

create equipotential zones at work sites. The main findings of the project are

summarized as follows:

- The portable bonding mat with its current design cannot create an acceptable

equipotential zone, from the perspective safe touch/step voltages. This finding is

valid regardless of whether the mat is bonded to a grounding structure or not.

The scientific reason behind the above findings is the following: an array of

meshed conductors laid on the ground surface cannot equalize the surface

potential to an acceptable level when they are energized.

- The specifications for designing, testing and inspecting the mats need

improvement. It is not clear what the technical justifications for some of the

specifications are. This report has shown how to establish proper specifications

and test procedures.

- Since the mat cannot create an equipotential zone but it can bring high voltage

closer to a worker under certain energization scenarios, the use of the mat could

actually increase electric risk to workers.

- The mats can be improved in two ways. The first is to make the fabric layer

dielectric and the other is to reduce the mesh size. Only the second option may

lead to the creation of (approximate) equipotential zone.

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Report No. 2012A-7

Low Frequency Magnetic Field Measurement of Utility Revenue Meters

and Home Appliances

February 2013

This report documents the findings on the Magnetic Field (B-field) measurement

results for utility revenue meters and common electrical appliances. Some Albertans

are concerned about the Electromagnetic Field (EMF) produced by utility revenue

meters. The University of Alberta, sponsored by the Alberta Power Industry

Consortium, initiated a project to help addressing this concern. The approach is to

measure, analyze and compare the low frequency magnetic field at homes with and

without revenue meters.

A magnetic field measurement system was developed for this project. B-field

emissions at five residential locations (four houses and one apartment) were

measured. The B-fields generated by 22 common electrical appliances were also

measured. The data are analyzed and compared. The main conclusion is that the

utility revenue meters do not produce additional consequential magnetic fields.

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Report No. 2012B-2

A Novel Zero-Sequence Harmonic Filter for Telephone Interference Mitigation

January 2013

The mass penetration of both energy efficient and consumer electronic devices in

homes have resulted in excessive harmonic distortions in residential feeders. One of

the consequences is the telephone interference problems experienced by three of

the APIC companies. This report presents a novel filter conceived to mitigate such

telephone interference problems. The idea is based on the concept of passive zero-

sequence harmonic filter modified with a double-tuning capability. This feature

makes it possible to trap two harmonics, such as the 9th and 15th harmonics, with

the filter. As a result, it is especially attractive to solving harmonic-caused telephone

interference problems. A practical method for sizing and designing the filter has also

been proposed. As an example application, the proposed filter package has been

applied through simulation studies to mitigate a telephone interference problem in a

feeder operated by EPCOR. Issues such as filter location, the number of filters

required and the effectiveness on filtering harmonics produced by distributed

residential loads have been investigated. The results show that the proposed filter is

a very promising technique to reduce zero sequence harmonics in general and to

mitigate telephone interference in particular.

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Report No. 2012B-5

Fault Current Contributions of Distributed

Generators and Their Impact on

Overcurrent Protection

December 2012

Distributed Generators (DGs) are known to contribute fault currents to their

interconnected power system. As a result, there is a concern that the DGs may

affect the coordination of overcurrent (O.C.) protection in a distribution system. This

may cause miscoordination among O.C. devices, nuisance tripping and relays’ reach

reduction (desensitization). This report presents the findings on the contributions of

DGs to fault currents and their probable impacts on the O.C. protection coordination.

Three types of DGs have been investigated. They are Inverter-based DGs (IBDGs),

Induction-Machine DGs (IMDGs) and Synchronous-Machine DGs (SMDGs). Fault

current contributions of each type are analyzed and simulations are presented to

support the analysis. The magnitude and duration of the currents are then assessed

from the perspective of relay coordination. This research found that the inverter-

based and the induction generator based DGs have negligible impact on overcurrent

protection. The synchronous machine based DGs are the only type that may cause

miscoordination when instantaneous, extremely inverse and, in some cases, inverse

overcurrent protection schemes are involved.

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Report No. 2012A-6

Harmonic Distortion Levels Measured at

The ENMAX Substations - 2012

October 2012

This report documents the findings on the harmonic voltage and current levels at

ENMAX Power Corporation (EPC) substations over a two year period. ENMAX is

interested in gaining an understanding on the harmonic levels in some of its

transmission substations and their trend in recent years. The University of Alberta

team initiated a project to help addressing this interest. The approach is to measure,

analyze and compare the harmonic currents and voltages at the substations of

interest to Enmax.

Harmonic voltage and current field measurements were carried out during a one-

week period in August 2012 at several ENMAX substations. This is the second time

to collect the data. Similar measurements were carried out in August 2011. The data

have been analyzed and compared in this report. The results include the daily

profiles as well as the statistical distributions of the harmonic voltage and current at

both phase and sequence domains.

This project did not study if the measured harmonic levels are high or low, or how

they compare with standards or other data. These are not the objectives of the

project.

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Report No. 1.1

Identification of Harmonic Polluters

December 2011

Harmonic distortion is one of the main power quality problems for power system

utilities. Nowadays, there are many harmonic-generating loads in a given distribution

or sub-transmission system. These loads typically have comparable sizes and are

scattered all over the system. Developing methods and techniques to quantify the

harmonic impacts of the customers and the utility system, especially when a

harmonic problem occurs in a system, is highly important for power quality

management. Unfortunately, there are no viable techniques that can pinpoint which

customers cause harmonic distortions problem at a specific location of a system.

This report presents a data-based method and associated techniques for

determining the individual harmonic impact of multiple harmonic-producing loads

scattered in a power system. To facilitate technology transfer to the consortium

members, this method has been implemented in a software package, which is

available to APIC members. This reports covers following topics.

1) A quick tutorial of the provided software and two application examples.

2) The technical principal of the software.

3) Verification studies of the proposed methods and sensitivity analysis.

28


Report No. 2011A-1

Harmonic Distortion Levels Measured at

The ENMAX Substations - 2011

October 2011

This report documents the findings on the harmonic voltage and current levels at

ENMAX Power Corporation (EPC) substations. ENMAX is concerned about the

harmonic impact of future HVDC converters to be implemented close to its

substations. The University of Alberta team initiated a project to help addressing this

concern. The approach is to measure, analyze and compare the harmonic currents

and voltages at substations close to the future converter stations before and after

the HVDC energization.

Harmonic voltage and current field measurements were carried out during a one-

week period in August 2011 at several ENMAX substations. This is the first time to

collect the data. Similar measurements are planned for next year (February 2012

and August 2012) and thereafter. The collected data have been analyzed and

presented through typical PQ indices and under different perspectives in order to

facilitate comparison with future field measurements. The results include the daily

profiles as well as the statistical distributions of the harmonic voltage and current at

both phase and sequence domains. Comparative harmonic level analysis will be

conducted after collecting more data in the future.

29


Report No. 3.3 (Task 2)

Modelling of Variable Frequency Drives for

Power System Dynamic Studies

Part 1: Implication of VFD Trip Characteristics on Dynamic Simulation

August 2011

Variable Frequency Drives (VFDs) are widely used in various industrial applications

and make an increasingly large portion of total loads in industrial facilities. However,

dynamic models of VFDs are currently not available for power system dynamic

studies.

This report presents the first set of research results on the subject of developing

models of VFDs for power system dynamic studies. It clarifies how a VFD responds

to voltage sags. Voltage sags occur when power system experiences short-circuit

faults, which is typically the starting point of power system dynamic simulation. This

research shows that VFDs will trip when they experience a relatively large voltage

sag (>20% - 30% voltage drop). As a result, there is no need to include VFDs in

dynamic studies under such conditions. Based on the finding, a simple procedure to

determine if a VFD needs to be included for dynamic studies is proposed and

presented in this report.

How to model VFDs when they experience mild voltage disturbances is still under

investigation.

30


Report No. 1.2

Advanced Load Shedding Scheme

April 2011

This project investigates an advanced load shedding scheme for the Alberta Integrated Electric

System (AIES). Based on the experiences of existing load shedding schemes and the advancement

of power system communication technologies, an event-driven load shedding scheme is proposed. In

this scheme, load shedding is triggered by outage events reported by the SCADA system or other

means and is initiated from the control center. The locations and amounts of loads to shed are based

on pre-established shedding tables. This is similar to the transfer trip scheme but it is done on a

system-wide scale and the settings are adjusted continuously according to the system conditions. A

design procedure for the proposed scheme has been developed through a series of analytical and

simulation studies. The main findings of this project are summarized as follows:

- An extensive review on the industry implemented load shedding schemes and on the operation

conditions of AIES suggests that an event-driven load shedding strategy is the most attractive

option for AESO.

- The load shedding locations can be obtained by following the proposed planning studies. The

planning studies also provides a set of load shedding actions, including load shedding locations,

amount, and maximum allowed time-delay for each critical contingency.

- The load shedding amount will be updated online by using the established system-condition

based tuning procedure. The tuning process can operate in a time cycle or be manually triggered

by the system operator or automatically triggered by the user-defined criteria.

- The maximum allowed time-delay of the load shedding actions is evaluated through time domain

simulation. If adjustments are needed for time delays, a bisection search method has been

proposed to find the proper values.

- A python-based add-on program for PSS/E has been developed by this project to facilitate

designing and tuning the event-driven load shedding rules. An event-driven load shedding

example on the AIES is given at the end of the report to illustrate how to use the python add-on in

PSS/E.

31



Assessment and Mitigation of Harmonics in Power Distribution Systems

Task 2: Telephone Interference Encountered in an ATCO Distribution System

December 2010

This report documents the findings on the telephone interference problem in the

Goodfare area supplied by ATCO Electric. The problem was investigated through

field measurements and computer simulation studies. The project found that the

telephone interference problem was caused by distributed harmonic sources

residing in the residential houses. The harmonic currents injected by these loads

collectively lead to a high level of zero sequence 9th harmonic current flowing in

ATCO feeder 5L405. A comparative analysis of the results measured from different

feeders and from extensive harmonic simulations indicates that the high zero

sequence harmonic current distortions not unique to feeder 5L405. It seems that the

electrical nature of present-day home appliances have resulted in wide-spread

increase of zero sequence harmonics in residential feeders. A rough estimate is that

each 1 MW load (at 25kV) will increase the power line IT by 170A. Both power and

telephone companies need to adjust their expectations on the power quality levels of

residential feeders and to develop a harmonic management strategy accordingly.

32



Assessment and Mitigation of Harmonics

in Power Distribution Systems

Task 3: Telephone Interference Encountered in EPCOR Summer Side Area

August 2010

This report documents the findings on the telephone interference problem along the 41st Ave SW in

Edmonton and its utility-side solutions. The problem was investigated through field measurements

and simulation studies. Several days of field measurements were conducted in the area. With the

support of Telus, voltages induced on a telephone line have also been measured.

The field measurements revealed that the high IT levels measured have similar characteristic to other

residential feeders recorded in the past. There are no specific causes of high IT level unique to the

Summer Side feeders. The 9th harmonic was found to be the main contributor to the telephone

interference level. Further studies revealed that feeder 21SU is the main contributor to the telephone

interference problem along the 41 Ave.

Simulation studies have shown that improvements on grounding points (i.e. reducing grounding

resistances) and load balancing do not yield noticeable reduction on telephone interference level.

Eliminating broken neutral points in the zone parallel with the telephone circuit will reduce the

telephone interference level. Two types of tuned zero sequence filters, Yg/∆ transformer-based and

shunt capacitor-based, have been found effective to reduce the telephone interference level.

This project once again showed that the high IT levels have become a norm for residential feeders.

As confirmed by simulation results, such IT levels are actually expected. All residential feeders with

regular demand levels are very likely to exceed power IT limits specified for industrial customers. The

implication is that harmonics from home appliances have become a major source of harmonic

pollution in power systems and they shall become a serious concern to utility companies. Broader

strategies are needed to address the problem. As for the specific problem of telephone interference,

this project has presented some promising utility-side solutions. However, the final solution to each

problem needs to take into account the costs of both utility-side and telephone-side solution options.

33


Report No. 2.1

Fault Detection in De-Energized Distribution Power Line

December 2009

Before reclosing the circuit breaker, a need exists to check if the downstream still

experiences a fault. A novel power electronics-based fault detection scheme has

been developed and verified in both theoretical analysis and computer simulation.

Compared to other existing methods, the proposal has three significant benefits: (1)

a controllable power electronics-based signal generator, (2) capability of detecting

different kinds of faults in a single device and (3) capability of distinguishing a fault

from a capacitor bank or a stalled motor.

To further investigate the performance of the proposal, a real-time lab test has been

carried out recently in the PDS-LAB. Instead of based on a real distribution line, the

voltage source for this test is from the 120V, 60Hz power outlet in the lab. All

parameters of the lab test circuit are therefore scaled down from the 25kV-based

computer simulation model. A thyristor is controlled to inject a detection signal to the

test circuit and both voltage and current pulses are captured. The corresponding

harmonic impedance is calculated from the analysis of the voltage and the current in

frequency domain. The effects of a stalled induction motor are also presented. At

last, the actual fault conditions (using tree branch and dirt) are tested and compared.

34


Report No. 1.3

Measuring the Load Model Parameters

December 2009

The objective of this project is to develop algorithms for the online measurement and

monitoring of power system load model parameters. In this report, the existing load

modelling algorithms in literature have been reviewed, the load parameter

measurement problem is formulated and solution algorithms are proposed. An

algorithm is proposed to detect the tap movement using the step change in voltage

waveform. The proposed tap change detection and load modelling algorithms have

been verified using several field measurements from different substations. Moreover,

sensitivity studies have been done to investigate the characteristics of the tap

movement. The results show that the proposed algorithm can fulfil the load model

parameter measurement requirements.

35



Modeling of Industrial Facilities for Power System Dynamic Studies

November 2009

Presently, models for industrial facilities are usually not available for the utility long-

term planning study and operation study. Such facilities typically draw large amounts

of power and have complex dynamic responses to power system disturbances.

Traditional load modeling approaches such as those based on load composition or

site measurement are not adequate to produce dynamic models for such facilities.

Extensive literature review indicates that no such work has been done or attempted

in the past.

In this project, a facility template based load modeling technique along with template

scaling/equivalence algorithms is proposed to solve the facility modeling problem.

Oil refinery facilities are used as an example to illustrate the proposed modeling

technique. The technique requires minimal user input and can be implemented in a

database program. A complete information has been provided for creating a

dynamic load model for oil refinery facilities.

36



Assessment and Mitigation of Harmonics

in Power Distribution Systems

Task 1: Telephone Interference Encountered in an EPCOR Distribution System

September 2009

This report documents the findings on the telephone interference problem in the Ellerslie Road are of

Edmonton. Objectives of the project are to develop techniques for assessing and troubleshooting

harmonic problems in residential feeders and to research filtering methods to mitigate the harmonics.

The project found that the 23E feeder’s telephone interference problem was caused by distributed

harmonic sources residing in the residential houses. The harmonic currents injected by these loads

collectively lead to a high level of zero sequence 9th and 15th harmonic currents flowing in the feeder.

The 9th harmonic is the main component resulting in the telephone interference. In addition, a 9th

harmonic resonance experienced by the feeder exasperated the problem. A comparative analysis of

the results measured from different feeders indicates that high harmonic current distortions are not

unique to feeder 23E. Almost all residential feeders have comparable harmonic current levels and

spectral characteristics. Some of the feeders exhibit a very high IT level. It is also found that

residential loads produce more zero sequence harmonics than commercial and industrial loads. In

view of these findings, the project developed a simple and approximate chart for APIC members to

check if a feeder may experience zero harmonic resonance.

In summary, this task has identified successfully the causes of the telephone interference problem in

the Ellerslie road area. The results further suggest that distributed harmonic sources in residential

loads have emerged as a major cause of harmonic concern in power distribution systems. The next

goal is to research techniques to mitigate such harmonic problems. Before this task is attempted,

however, we intend to investigate one more real case reported in the ATCO system. Such an

additional case study will help to confirm the above findings so mitigation solutions to be developed

will have general applications.

37



Truck-Grounding Issue Investigation

March 2009

This report is prepared to provide technical information that electric utility companies may use to

determine working practices and procedures for working with non-insulated vehicles in the vicinity of

primary energized overhead distribution lines. The report considers grounding, barricading and other

methods that may be used to prevent or minimize injuries due to inadvertent contact of the vehicle

and equipment with energized lines.

This project has identified four safety options for utility companies to consider (1) grounding, (2)

barricading, (3) using an isolation mat and (4) wearing insulating boots/gloves. The grounding option

has been narrowed down into two choices (1) grounding to the system neutral or rod and (2) no

grounding. A utility company may mix and match these options to create a safety package for the

workers. Table 5.1 summarizes all possible combinations for consideration by the project sponsors.

Table 5.1: Possible safety packages for consideration by utility companies

Package No. Grounding* Barricade Isolation mat Boots/Gloves

Combination of all options 1 Yes Yes Yes Yes

Combination of three options

2 Yes Yes Yes No

3 Yes Yes No Yes

4 Yes No Yes Yes

5 No Yes Yes Yes

Combination of two options

6 Yes Yes No No

7 Yes No Yes No

8 Yes No No Yes

9 No Yes Yes No

10 No Yes No Yes

11 No No Yes Yes

Individual option

12 Yes No No No

13 No Yes No No

14 No No Yes No

15 No No No Yes

*Means grounding to system neutral or rod

38



Wire to Earth Voltage Comparative

Analysis for Underbuilt Circuits

January 2009

This report presents results on the GPR (ground potential rise) characteristics and values at the multi-

grounded line configuration where a distribution line is installed below a transmission line in the same

tower structure. The GPR results of such a configuration are compared to those associated with

common single circuit configurations. The results are obtained through extensive analytical studies

and computer simulations. The main findings are summarized below:

- The under-built MGN distribution line has no adverse effect on the shield potential rise (SPR) of

the corresponding transmission line, i.e. the maximum SPR does not increase when a D-line is

added. This is because the highest SPR is caused by T-line faults and the D-line configuration

has little impact on this value.

- The above conclusion is valid even if one considers the fact that a T-line normally has a much

shorter fault clearing time than a D-line. More specifically, as long as the fault current of a T-line is

1.76 times greater than the D-line fault current, the T-line fault caused GPR poses higher safety

risk than the (underbuilt MGN) D-line fault. This is partially due to the fact that the electrocution

risk to humans is in proportion only to the square root of the fault clearing time.

- The D-line neutral points will experience higher neutral potential rise (NPR) when a fault occurs in

the overbuilt transmission line and if the T-line fault current is about 2.5 times higher than the D-

line fault current. This is in comparison to the NPR produced by a D-line fault. Shield wire of the

T-line has little impact on the maximum NPR (produced by the T-line fault). However, bonding

can significantly increase the NPR to about 1.6 times greater than that of the unbonded case,

during T-lien to shield (tower) faults.

In conclusion, there is no evidence to support the concern that an underbuilt distribution line poses

additional GPR-related threats to the transmission line. On the other hand, the designers of the

underbuilt D-lines shall pay attention to the higher NPR which may occur when the overbuilt T-line

experiences a phase-to-shield, phase-to-tower or phase-to-ground fault.

39


Report No. 3.2

A Practical Guide for Motor Starting

Planning

October 2008

The power quality impact of motor starting is a concern to utility companies. This

concern is especially important in Alberta due to the presence of a large number of

industrial facilities and the relatively long distribution lines. Although there are

various ways to reduce the impact of motor starting, almost all of the solutions need

to be planned and designed before the motor and its facility are connected to the

system. Furthermore, new power quality standards such as the IEC flicker meter are

gaining acceptance and it has become necessary to consider these standards when

conducting the motor starting planning studies.

The objective of this report is to provide technical information to support the motor

starting planning study from the utility’s perspective. The report attempts to address

all key issues involved in the study and to provide practical ways for efficient motor

starting impact assessment. The topics covered by this report include: 1) power

quality issues associated with motor starting, 2) customer and utility side solutions to

the motor starting problems, 3) methods for motor starting study and 4) practical

tools for quick screening of motor starting problems. These practical tools, called

motor starting guideline charts, are developed according to the latest IEEE power

quality standards. They help a planning engineer quickly estimate if a motor

installation can cause voltage sag or voltage flicker problems. He or she can then

decide if detailed motor starting study is required.

40


Report No. 3.4

Determining Acceptable AIES System

Restoration Island Synchronizing

Parameters

August 2008

This project investigates the main technical issues associated with the re-synchronization of islanded

Alberta Integrated Electric System (AIES). It determines if the current synchronization relay settings

are adequate and recommends changes if required. Through a series of analytical and simulation

studies, the impact of each synchronization parameter on generators and overall system performance

has been identified. The study further established analytical methodologies for interpreting the

simulation results by revealing the nature and mechanism of the synchronization disturbances.

Synchronization protection settings for AIES are recommended. The main findings of this project are

summarized as follows:

- The generator-system synchronization produces the highest transients on the generators in

comparison with the island-island synchronization cases when same synchronization criteria are

used. The implication is that if one adopts the relay settings of generator-system synchronization

to island-island synchronization, the impact of the synchronization transients on the generators

will be less than that produced by the generator-system synchronization.

- The results further show that the island-island synchronizing angle can go as high as 20o while

the resulting impact on generators is still within those produced by the generator-system

synchronization conducted at 10o. A frequency different up to 0.3Hz during island-island

synchronization can be tolerated from the perspective of impact on the generators. From the

stability and implementation perspectives, however, it is more desirable to keep the frequency

deviation within the 0.067-0.1Hz range.

- The voltage magnitude difference has the lowest impact on all indices except for the sudden

change in generator terminal voltages and in generator reactive power. Although the sudden

voltage change is within 5% for most generators, generator units at bus #350 and 1482 need

special attention to prevent higher voltage change beyond 5% during synchronization.

41


Report No. 1.4

Measuring the Supply System Impedance

Parameters

August 2008

The objective of this project is to develop algorithms for the online monitoring and

measurement of power system equivalent circuit parameter, such as the supply

system impedances. In this report, the measurement problem is formulated and

solution algorithms are proposed. Practical issues encountered for impedance

determination are investigated and solutions are developed. The proposed method

has been verified using computer simulation studies and several field measurements.

The results show that the proposed algorithms can fulfil the impedance

measurement requirements.

42


Report No. 4.1

Survey of High-Impedance Fault Detection

Techniques

April 2008

High impedance faults usually occur at primary network level in electrical distribution

systems. They can be described as those faults which do not draw sufficient current

to be recognized and cleared by the over-current devices in common use in the

utility industry. Research on high impedance fault detection has been conducted for

decades. However, a complete solution has not yet been found. Not only is the

current too small, but also because distinguishing high impedance faults from normal

operations are very complicated as various normal operations unfortunately create

the similar transient as HIF. The development of high impedance fault detection

techniques is reviewed in this paper while individual techniques are analysed and

classified. Composite systems which are implemented to overcome the

disadvantage of single techniques are also introduced. Moreover, alternate solutions

including mechanical techniques and remote techniques are presented. Finally,

possible improvements are proposed at the end of this paper.

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