Voltage fluctuation source localization in distribution systems using a signature-based approach with minimal monitoring points

Reducing or eliminating voltage fluctuations, a key power quality issue that causes many problems such as flicker, hinges on accurately identifying their sources. The complexity of distribution systems adds further challenges to this task. On the other hand, there is a limitation in providing power quality measurement devices (PQMDs) compared to the number of buses in these systems. Therefore, this paper introduces a simulation-based approach for pinpointing voltage fluctuation sources (VFSs) in distribution systems, specifically for frequencies up to three times the network frequency, using a limited number of PQMDs. The proposed method simulates potential VFS locations and applies a trial-and-error approach, comparing a defined signature from the simulated system with that of the real system to find the closest match to the observed network behavior. Additionally, this method employs a novel carrier signal estimation technique for demodulation and a pulse-wave approximation method for decomposition of rectangular amplitude modulation. To validate the method, simulations were performed under various scenarios on the 15-bus system, the IEEE 33-bus standard test system, and the 70-bus test system. The simulation results demonstrate 99.4%, 97.8%, and 99.5% accuracy in identifying the VFS location in the 15-bus, 33-bus, and 70-bus test systems, respectively, while using only 3, 4, and 14 PQMDs.