Analysis of inrush current and over-voltage with HVDC AC filters switching on

The number of the faults caused by AC filters has been reached 8 times in a HVDC system of CSG. The AC Filter may produce inrush current and over-voltage when switching on, which will occasionally damage the filters, make protection malfunction and threat the system. The paper introduces a simulation based on Monte Carlo algorithm and PSCAD User-definition model in order to analysis the problem. This paper makes simulations about inrush current and the zero sequence current to research three-phase unbalanced inrush current in the inverter side. Based on these results, some methods which solve the effect of inrush current has been proposed, like erecting POW, locking the unbalanced protection temporarily.