Mitigation on Sympathetic Inrush Current Phenomena between Parallel-Connected Transformers using PSCAD/EMTDC

Abstract

In renewable energy sources, one of the most rapidly developing is wind energy. Wind turbine transformers are connected between the wind turbines and the distribution grid. Transformers have accessibility to play as key part in the overall power system. The magnetization of a wind-turbine transformer is frequently related with the inrush current phenomena. Magnetising inrush current perform as a start-up current which is develops in a transformer once it is turned on for the first times. The switched-on transformer is not only giving effects to the inrush current but it also had a significant impact on the parallel-connected transformers. This phenomenon called as sympathetic inrush current whereas it occurs once the transformer is turned on in a circuit while having another transformer that was previously energized. During the energization process, it has an unexpected saturation and once the transformer is saturated, transients develop, resulting in mal-operation of the protective relay and harmonic over-voltages. The magnitude and duration of the magnetising inrush current are dramatically changes when the phenomenon of sympathetic is occurred. In this research, the PSCAD software is utilized to develop a sympathetic inrush model and obtain the simulation results. According to simulation results, the proposed technique may efficiently identify sympathetic inrush. This paper examines the sympathetic inrush current phenomenon, as well as the factors that influence it and how to mitigate it.