Power Quality: A 25-Year History and What’s Next

Published by Tom Key, EPRI PEAC, Knoxville, TN, Email: tkey@epri-peac.com, 2003




Power Quality Case Studies – Understanding compatibility issues
DPQ Project – Benchmarking system power quality
Advancements in power quality monitoring and managing power quality monitoring information – PQView
Tools for power quality analysis – PQ Diagnostic System
Power Quality Services – Is it a business or a customer service?


The DPQ Project benchmarked PQ on distribution systems in the US
Many utilities followed with extensive benchmarking projects for their individual systems.  This continues to be a priority.
This also resulted in tools and indices for benchmarking – Reliability Benchmarking Methodology and PQView.
Another way of showing the same data..  This includes durations which are the result of fault clearing times.













Internal facility problems dominate the issues – Wiring and grounding problems, Connections, Internal switching concerns, Load variations and, harmonics affecting the facility voltage
Some utility issues – Capacitor switching concerns, Harmonic resonance, Voltage sags and momentary interruptions due to faults, Voltage variations (flicker)
All power quality issues come down to economics.
Finding the most cost effective way to solve problems and identifying the investments that are economically justified require a systems approach to the economic analysis.
This is a significant area of research – how much do power quality problems cost?
How much should utilities invest in improving power quality vs investments from customers in improving immunity?
Many utilities experimented with PQ programs as profit-making service opportunities.
For a variety of reasons, most of these did not succeed.
SEMI F47 Provides a template for development of standards that can improve the performance of equipment in critical industries
 : Utilities, Manufacturers, End Users
Now working with other industries to develop similar approaches to improve compatibility.: Automotive initiative is under way right now, Textiles, Hospitals, Plastics, Petrochemical etc.
Standards development is ongoing. 
The emphasis right now is trying to bring an international perspective to standards.
What are the compatibility levels?
How should we measure and document PQ?
How should limits be applied to equipment, customers, the supply system?
Power quality must be a business.
All investments must be justified.
Regulations must be developed to support flexibility in implementation of power quality solutions at all levels of the system.
Power quality standards become international
PQ Monitoring is everywhere
Power quality management becomes part of system operations
Planning for power quality
Providing flexible levels of power quality to meet customer needs
Expert systems to identify problems use power quality monitoring information
Power quality MUST be a business
The whole system will be monitored.
These systems will be part of systems operation and system maintenance programs.
The monitoring systems can be the basis of future premium power service offerings, distributed generation performance, customer system performance, etc.
The monitoring systems will integrate equipment for many applications (relays, meters, controls, etc.)
Intelligent applications will be built off the voltage and current monitoring.
All power quality parameters that can impact customer and system operation will be tracked continuously.
The information will be used as part of overall system performance evaluation and prioritizing expenditures to improve performance.
PQView provided the capability to analyze large volumes of information.
PQWeb set the stage for sharing information in the easiest manner – the web.
The opportunity to provide flexible levels of power quality requires innovations in the regulation of utilities and technology implementations to achieve the flexible levels of power quality.
Smart monitoring systems will help us operate the power system, identify problems and fix the problems faster and more efficiently.
Fault location, Equipment problems, System efficiency etc.

Quality and Reliability are not POINT values
System level indices need to move down to substation/feeder level in a probabilistic framework to better define consumer risk.

Published by PQTBlog

Electrical Engineer

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