References for SARFI PQ Index

Published by Terry Chandler, Director of Engineering, Power Quality Thailand LTD/Power Quality Inc., USA. E-mail: terryc@powerquality.org, terryc@powerquality.co.th FYI, PQView calculates these automatically from the PQView database of all instruments. For more information on PQView, you can visit the blog post PQView & PQView DE System Average RMS (Variation) Frequency represents the average number of specified rms variation measurementContinue reading “References for SARFI PQ Index”

Interpretation & Analysis of Power Quality Measurements

Published by Christopher J. Melhorn, Electrotek Concepts, Inc. Knoxville, Tennessee Mark F. McGranaghan, Electrotek Concepts, Inc. Knoxville, Tennessee ABSTRACT This paper describes advances in power quality monitoring equipment and software tools for analyzing power quality measurement results. Power quality monitoring has advanced from strictly problem solving to ongoing monitoring of system performance. The increased amountContinue reading “Interpretation & Analysis of Power Quality Measurements”

Simple Rules for Solving Power Quality Mysteries

Published by Richard P. Bingham, Dranetz Technologies, Inc., USA Prepared for the Conference on Protecting Electrical Networks and Quality of Supply, Heathrow, UK, 22-23 January 1997 ABSTRACT The typical power quality problem starts with a frantic call to the facility’s engineer or electric shop supervisor concerning some malfunction that has either shut down production orContinue reading “Simple Rules for Solving Power Quality Mysteries”

Determining Sag Directivity

Application Note INTRODUCTION Voltage sags, or dips are the most common type of power quality (PQ) event. Knowing the directivity of the sag, or where it originated, is very import when trying to locate its source and to ultimately mitigate the problem. This application note outlines some rules of thumb to help determine the directivityContinue reading “Determining Sag Directivity”

Loose Bus Bar Bolts Cause Sags

An administration building in a government complex in New Jersey had a transformer with a 4KV primary, 120/208V wye, 800A secondary. The buss duct ran up to a second-floor panel, which supplied an office area. Computer misoperations and lights flickering were occurring randomly for nearly two years. Emergency lighting was also flickering. Three voltages andContinue reading “Loose Bus Bar Bolts Cause Sags”