Influence on power quality measurement of the simultaneous presence of different disturbances

Abstract

Power Quality measurements involve not only problems related with the real use of recorders but also theoretical questions connected with functional and design aspects of the instrumentation. In addition, there are a rising number of standards covering topics from design to data analysis, so final users usually assume that they do not have to pay special attention to PQ instrumentation functionality when the device is designed according to approved standards. However, it is not unusual to find different disturbances at the same point and in the same time and standards do not say anything about their mutual influence on PQ index. The main aim of this research work is to show the influence that having different disturbances (flicker and sags) simultaneously has on the final results provided by the instrumentation for each individual disturbance. The paper proposes a test system and a methodology. The results of various tests using commercial and research instrumentation are presented and some possible solutions to these problems are considered.