Analysis and Simulation of Monopolar Grounding Fault in Bipolar HVDC Transmission System

The paper analyses the monopolar grounding fault in bipolar HVDC system with phase-modal transformation method. Initial jumping voltage and maximum voltage on health pole with different kinds of termination are deduced by establishing the modal circuit under the fault. Simulation results show a grounding fault in the middle of the line exhibiting maximum voltage with value of 1.54 p.u, which agrees well with the theoretical value. And the maximum voltage decreases with the increasing grounding resistance. The inductance of the reactor influences the maximum voltage on health line a little.