Power Quality Monitoring

Abstract

Power quality is the measure, analysis, and improvement of a load bus voltage, to maintain that voltage to be a sinusoid at rated voltage and frequency. The phenomena related to power quality are generally physical stochastic events in the sense that in many cases are appearing and disappearing arbitrarily. Therefore, power quality measure is more than a simple measurement of an electrical parameter; i.e. it is necessary to record them over an enough long time interval. In order to reduce the huge amount of data by recording and analyzing several electrical parameters over a long period of time, some recording limits are set. If these limits are exceeded, the monitoring instruments evaluate the raw data and record only the essential data of the important events. There are several reasons for monitoring power quality. The most important reason is the economic damage produced by electromagnetic phenomena in critical process loads. Effects on equipment and process operations can include malfunctions, damage, process disruption, and other anomalies. It is noted that monitoring, alone, is not the solution for power quality problems. In order to solve the power quality problems, some other remedies more than the installation of power quality monitors are needed. In fact, monitoring provides the essential data which are needed for the improvement of power quality. In many projects related to finding a solution for power quality problems, monitoring plays a decisive role, and, therefore, managing monitoring properly helps to minimize the cost of solving problems. The recorded power quality data depends on the way the instruments record the disturbance levels and how the signals are interpreted. In order to have a correct interpretation of the recorded data, users need to know the specifications of the monitoring instruments such as sampling rate, accuracy, resolution, anti-aliasing filter. The misinterpretation may result in non-existent errors and recording disturbances which in turn may lead to incorrect conclusions and costly decisions. Effective monitoring programs are important for power reliability assurance for both utilities and customers. It is worth pointing out that most customer power quality problems originate within the customer facility. Monitoring power quality ensures optimal power system performance and effective energy management. Voltage sags, harmonics, interruptions, high-frequency noise, etc., are the most important power quality problems which are seen in industrial and commercial installations. Troubleshooting these problems requires measuring and analyzing power quality and that leads to the importance of monitoring instruments in order to localize the problems and find solutions. Although the