Sensitivity analysis on short-circuit current contribution from VSC-HVDC systems connecting far and large offshore wind power plants

This paper discusses grid code compliance for point-to-point VSC-HVDC systems used for the grid connection of far and large offshore wind power plants. The study focus on the short circuit current contribution provided by VSC-HVDC system delivery. Sensitivities such as the reactive current boosting gain of the AC voltage controller, the choice of dead-band and the method prioritising active versus reactive current during faulted conditions are discussed with focus on power system voltage and rotor angle stability of a multi-machine power system. The paper shows that prioritising the reactive short circuit current versus active current leads to improvement in both voltage response and transient stability of the AC power system. In addition, the removal of the dead-band while increasing the proportional gain of the AC voltage controller is proved to be beneficial for the power system stability. The analysis is based on time domain simulations using the IEEE 39-bus test system and user-developed models of VSC-HVDC systems in PSS®E.