Switch Status Identification in Distribution Networks Using Harmonic Synchrophasor Measurements

Switch status identification (SSI) in distribution networks is a challenging task due to the limited measurement resources and therefore the inevitable need is to use pseudo-measurements that are often inaccurate. To address this issue, a new method is proposed in this article to integrate harmonic synchrophasors into the SSI problem in order to enhance SSI accuracy in distribution networks. In this method, switch status identification is done jointly based on both fundamental synchrophasor measurements and harmonic synchrophasor measurements. This is done by formulating and then solving a mixed-integer linear programming (MILP) problem. Furthermore, an analysis is provided to capture the number of and the location of harmonic sources and sensors that are needed to ensure full observability. The benefits of the proposed SSI scheme are compared against those of the traditional scheme that utilizes only the fundamental measurements. The efficiency of the proposed method is demonstrated through numerical simulations on IEEE 33-Bus and 123-Bus test systems. The results show the advantage of using harmonic information in SSI over the traditional SSI schemes using sole fundamental measurements.