A Multi-infeed HVDC System: Assessment of Transient Overvoltages

The paper presents an electromagnetic-transient (EMT) analysis of a multi-infeed HVDC cable system in order to assess the transient overvoltages on the cables due to different fault conditions. It is well known that the HVDC-MMC configuration needs surge arresters to reduce the transient overvoltages on the DC cable system. This work highlights how the voltage perturbations on the HVDC-LCC link due to the faults on the HVDC-MMC link are not negligible and how a reduction of transient overvoltage is necessary for both the HVDC systems. The results of this study can be useful to improve the insulation coordination of the multi-infeed HVDC system and their reliable operation.