Research on Effective Parameters on Overvoltage and Inrush Current in Starting-up of VSC-HVDC System

The starting-up strategy is an important issue for voltage source convert-high voltage direct current (VSC-HVDC) system. If a VSC-HVDC system starts up without any auxiliary system, overvoltage and inrush current will occur. This large overvoltage can cause serious damage on the DC capacitors and this large inrush current at turn-on may destroy the switches in converter. In this paper, starting-up steps in a three-phase two-level VSC-HVDC system is studied with details. The effect of capacitor and inductor values and also circuit breaker closing time on overvoltage and inrush current are investigated attentively. Possible methods for control overvoltage and inrush currents during starting-up are presented, and a comparison has been made between them in terms of power dissipation and cost. Eventually, the best auxiliary starting-up system is selected in terms of costs. Substantial simulations conducted on PSCAD/EMTDC platform.