Overview

Foreword EPRI has been studying power quality (PQ) problems and solutions for over 15 years. This chapter presents many new and innovative approaches to PQ monitoring, analysis, and planning that have been developed since the First Edition of this book. The authors have been intimately involved in this research. Tremendous progress has been made and readers can gain a better understanding of the state-of-the-art of this research, which continues.

Power quality benchmarking is an important aspect in the overall structure of a power quality program. The benchmarking process begins with defining the metrics to be used for benchmarking and evaluating service quality. The EPRI Reliability Benchmarking Methodology project (EPRI Reliability Benchmarking Methodology, EPRI TR-107938, EPRI, Palo Alto, California) defined a set of PQ indices that serve as metrics for quantifying quality of service. These indices are calculated from data measured on the system by specialized instrumentation. Many utilities around the world have implemented permanent PQ monitoring systems for benchmarking power quality. However, there are still considerably large gaps in coverage of the power system with PQ monitors. As part of the EPRI Reliability Benchmarking Methodology project, investigators explored the idea of estimating the voltages at locations without monitors given the data at only one monitor or a few monitors. This resulted in the development of the concept of the EPRI Power Quality State Estimator (PQSE), which uses feeder models and recorded data to estimate what would have been recorded on the customer side of the service transformer.

This...