UHVDC test line is applied to research of environmental influence and to technical support to the construction of UHVDC transmission systems.Stable operation of the 1 200 kV/500 mA bipolar UHVDC voltage generator

which is the main power source of the experimental line in a test base

is very important for all the researches.This paper adopts the electromagnetic transient analysis software ATP-EMTP to simulate the transient characteristics of the generator in short-curcuit discharge and charging processes.Simulation results show that the maximum overvoltage on the main capacitors is 1.35 times of the normal one during the charging process

and the maximun transient peak current on the high voltage silicon stack may reach 9.3 times of the normal one under the EUT flashover or output short-circuit status.The output protecting resistor should be designed for operating under full-voltage with 50 A short-cucuit current.This study may benefit design and construction of the bipolar UHVDC generator.