Study on Overvoltage and Insulation Coordination of DC Filter for UHVDC Project

Based on the UHVDC project from Hami to Zhengzhou, two typical faults for transient stress calculation of DC filter including ground fault on the DC line and incoming switching surge on the DC line are presented. The simulation steep-fronted models and factors including protective characteristics of arresters, parasitic inductances should be considered for these two faults are introduced. The protective level of arresters are obtained according to the calculated maximum according current of arresters, and the insulation levels of the filter equipment are defined according to the insulation margin. The research can provide technical supports for project construction.