Common-Mode (CM) Current Sensor Node Design for Distribution Grid Insulation Monitoring Framework Based on Multi-Objective Optimization
Yang Wu, Pinjia Zhang
Abstract
Insulation monitoring is essential in maintaining distribution grid reliable operation and common-mode (CM) current is an effective indicator for insulation deterioration of electrical assets. Traditional CM current measurement relies on current transformers or sensors physically connected to transmission buses, which suffers from low accuracy due to accompanied load current disturbance. This article presents an innovative CM current sensor node for insulation monitoring framework of power distribution systems based on magnetic field analysis. A CM current measurement model is developed based on formal magnetic field solution and device design is characterized as a multiobjective optimization problem solved by Pareto envelop-based selection algorithm. A prototype is presented with tunneling magnetoresistive sensor and experiments on power cable CM current measurement are implemented. Compared with conventional measurement devices, proposed sensor node realizes high-accuracy CM current monitoring in a more flexible and cost-effective manner.