Electrical resonance instability study in HVDC-connected Offshore Wind Power Plants

The stability of an HVDC-connected Offshore Wind Power Plant (OWPP) is compromised if there are interactions between the power converters and the resonances of the offshore grid. This paper analyses the voltage stability of the offshore HVDC converter due to low frequency electrical resonances. An impedance-based representation is used to identify the resonances and study the stability. The effect of the offshore converter control and OWPP parameters is analysed through the root locus of the system. The positive-net-damping criterion is used to determine the stability conditions due to electrical resonances. Also, time-domain simulations in PSCAD/EMTDC are presented to verify the stability conditions.