A composite power quality index for low-voltage active distribution networks

Abstract

Abstract In active distribution networks, it is a challenging task for the utility and system operators to identify and analyze the power quality (PQ) disturbance and its cause. Likewise, the consumers are curious about the quality of power supply being provided and the economic impacts of low PQ. Thus, continuous monitoring of the overall quality of the power at the consumer end has become a significant concern in distribution networks. This paper presents a new composite power quality index (CPQI) for low-voltage distribution networks. The CPQI is formulated as a weighted average of five basic parameters, namely voltage level, current harmonic quality, voltage harmonic quality, power factor, and system frequency. The main emphasis is on quantifying the overall quality of the power supply under different PQ disturbance conditions. The CPQI estimate helps in a preliminary investigation of tracking the low PQ location and its source. The proposed CPQI is evaluated on a variety of simulated signals obtained from a CIGRE low-voltage microgrid network. Furthermore, the formulated CPQI is investigated on a LabVIEW-based virtual instrumentation platform with LED loads. It is interpreted from the results that the proposed CPQI is able to evaluate the overall PQ at a load terminal with diverse load conditions subjected to different power quality disturbances.