Impedance characteristics of loop closing device based on improved phase shifting transformer

Abstract

With the increasing reliability of power supply in distribution networks, loop closing operation is often required to achieve non-stop load transfer. Firstly, the loop closing device based on improved phase shifting transformer (IPST) can be effectively used in complex loop closing scenarios such as three-phase asymmetry and voltage magnitude difference between the buses on both sides of the loop closing point of the distribution network, considering that the internal impedance of the loop closing device has a certain influence on the quality of the loop transfer voltage. Secondly, the mathematical model of IPST equivalent impedance is established based on the basic principle of transformer, and the expressions of IPST equivalent impedance calculation and the factors affecting the size are derived and analyzed. Finally, the correctness of the proposed IPST-based impedance calculation expression for the loop closing device is verified by MATLAB and PSCAD/EMTDC simulation platform.