Grounding transformer application, modeling, and simulation

The grounding transformer is a transformer intended solely for establishing a neutral connection point on a three-phase ungrounded power system. The transformer is usually of the wye-delta or zig-zag transformer. This paper first reviews the state of the art of the grounding transformer to assist electric power engineers in the proper understanding of the use and applications of these devices, and then a zig-zag grounding transformer is modeled in PSCAD/EMTDC simulator. After a 27.6 KV ungrounded three-phase transmission system is constructed, different scenarios are simulated and verified under different conditions with the connection of the grounding transformer.