Optimal Monitor Placement for Voltage Unbalance Based on Distribution Network State Estimation

This paper develops a methodology for the optimal monitor placement of voltage unbalance, based on a limited number of monitors. As voltage unbalance causes overheating problems in both power system equipments and user devices, it is expected that this long term problem can be fully observed and mitigated if necessary. In this paper, by analyzing the importance of every bus against the monitoring of unbalance or measuring the uncertainty in the network, the best location of monitor with full observability of the network is recommended. Therefore, the financial budget for the installation and maintenance of the monitors can be optimized. The developed methodology, combining the uncertainty of state estimation and optimal monitor placement, is illustrated to provide the level of unbalance for both real-time measurement and long term prediction when some parts of the network are not observable. The study is carried out on a section of the UK distribution network and the results are compared to the actual monitoring data.