Analyzing and Minimizing Distribution System Harmonic and Transient Disturbances

What are Harmonic and Transient Disturbances?

Voltage disturbances can occur on electric power distribution systems that feed industrial plants, large commercial facilities, and residential neighborhoods. These disturbances can be transient impulses (lasting less than a few milliseconds), short-duration sags or swells (lasting between a few milliseconds and 1 minute), or they can be long term, repeating waveform distortion (harmonics). Even if they don't cause immediate outages, over time these disturbances can lead to mis-operation of sensitive facility loads or reduce the operating life of equipment.

What Will You Learn?

Categorize, identify, and mitigate both steady state and event disturbances from:

• Load Start-Up and Switching
• Capacitor Switching
• Lightning
• Dynamic Overvoltages
• Commercial and Industrial (C&I) Facilities
• Variable Speed Drives
• Wind and Solar Systems

• Electric utility engineers involved in distribution engineering, operations, or planning
• Electric utility customer service engineers
• Engineering technicians
• Electrical contractors for C&I customers
• Distributed renewable generation engineers
• Drive manufacturers and vendors
• Power distribution manufacturers and vendors
• Industrial plant and electrical system specifying engineers
• Electrical testing and commissioning engineers

This course will be beneficial if you are involved with maintaining power quality on electrical distribution systems.

Introduction to Power Quality

• Review of harmonic and transient power quality problems
• Introduction to industry standards
• EEE 519, IEEE 1250, IEEE 1159, and IEC 61000
• Harmonic and transient disturbance categories
• Common symptoms of and solutions for harmonic and transient problems
• Common solutions for harmonic and transient problems

Monitoring

• Defining objectives
• Equipment requirements
• Developing monitoring procedures
• Collecting data and analyzing results

Source Impedance

• Basics of distribution system Impedance
• Typical components impacting source impedance
• How source impedance affects system susceptibility to disturbances

Transient Disturbances

• Characterizing transient disturbances
• High frequency load switching
• Vacuum circuit breaker pre-strikes
• Vacuum circuit breaker current chopping
• Lightning
• Insulation coordination
• Transformer energizing and dynamic overvoltages
• Ferroresonance
• Utility capacitor bank switching
• Power factor correction capacitors
• Normal energizing transients during switching
• Voltage magnification
• Nuisance tripping of power-electronic equipment
• Restrike transients during switch opening
• Wind plant harmonic filter bank energizing
• Voltage notching
• Temporary overvoltages (TOVs)
• Single line-to-ground faults
• Wind plant TOVs during single-phase faults
• Summary of utility system transient mitigation
• Summary of facility transient mitigation

Transient Studies

• Common reasons for performing transient studies
• Study methodology and procedures
• Data collection and study set-up
• Overview of computer simulations
• Review of software options

Harmonics, Interharmonics, and Flicker

• IEEE 519 and IEC Standards
• Harmonics in commercial buildings
• Neutral current harmonics
• K-Factor transformer ratings
• Harmonics in industrial facilities
• Six-pulse and twelve-pulse drives
• Power factor correction and resonance
• Harmonic filters
• Harmonic filter class exercise
• Harmonics in renewable energy systems
• Interconnection requirements
• Resonance considerations
• Interharmonics and flicker
• Steel plants
• Induction furnaces
• Cycloconverters
• Inverter and converter based generation sources
• VFD and PV Inverter class exercises

Summary and Review

• Waveform recognition examples
• Case studies
• Student problems
• Q&A Session

"I think every topic was well covered and the instructors did a great job answering questions and tailoring the discussion to issues raised by attendants."
–Tony, Traverse City Light & Power, March 2018

 "I needed a general understanding overview on transients and harmonics and this course did that and then some."
–Brad, Northwestern Energy, March 2018

Thomas Grebe

Tom Grebe, PE, is a principal consultant with EnerNex in Knoxville, Tennessee. His primary responsibilities include consulting for electric utilities and their customers in the areas of power systems and power quality analysis. Grebe has over 30 years of application experience using the EMTP and PSCAD transient simulation programs. Grebe received his BS in Electrical Engineering from Penn State University. He is a senior member of IEEE, Past-chairman of the Capacitor Subcommittee, and Chairman of the Harmonic Filter Working Group.

David Mueller

David Mueller is the Director of Power System Studies with EnerNex. Since 1990 he has worked on a wide variety of projects to solve electric power problems. Dave has worked with companies such as Georgia Power, Dominion Resources, PSE&G, Duke Energy, Public Service of New Mexico, Delmarva Power, Wisconsin Electric Power Company, Con Edison of New York, Intel, Google, Apple, General Motors, East Midlands Electricity (UK), and the Electricity Supply Board (Ireland) to solve power quality problems.

Dave has also written many technical papers and articles on electric power quality,and has given over 100 presentations on these topics. He has presented these subjects in over 50 different cities,and has done work in over 25 different states in the U.S. Overseas, hehas presented power quality in around 13 countries.

Dave received a B.S.E.E. from University of Cincinnati, and a Master of Engineering from the Electric Power Engineering Department at Rensselaer Polytechnic Institute.

Kevin Rogers

Kevin Rogers is an electrical engineer with a background in electrical power systems. He is a registered professional engineer, and his 18 years of industry experience spans across electric utility, government, commercial, and industrial applications. His technical responsibilities have included design and commissioning of mission-critical facilities, underground medium voltage distribution planning, design, and operations, high-voltage substation design, and relaying protection and control for complex interconnections. Prior to joining UW-Madison's College of Engineering Office of Interdisciplinary Professional Programs (InterPro), Rogers served as the Engineering Manager for an electrical engineering consulting firm where he and his colleagues provided diverse engineering services across the electrical construction industry.