| Abstract |
In future high-voltage direct current (HVDC) systems, a large number of HVDC breakers will be re-quired. In this paper, the influence of HVDC breakers on the transient performance of point-to-pointHVDC links in both asymmetrical and symmetrical monopolar configuration with half-bridge modularmultilevel converters is studied with simulations in PSCAD. As HVDC breakers, the active resonantbreaker and ABB's hybrid breaker are considered. The analyzed scenarios include DC line faults, DCbus faults, and AC faults between the converter and the transformer. The highest DC breaking capabilityis required during DC line faults in the asymmetric and symmetric monopole. The converter stress ishighest for DC bus faults and unbalanced converter AC faults in the asymmetric monopole and for DCbus pole-to-pole faults in the symmetric monopole. During DC pole-to-ground faults in the symmetricmonopole, the HVDC breaker combined with DC side arrestors yields the lowest overvoltage stress onthe cable of the healthy pole. The fault current shapes depend strongly on the interaction of the converterand the travelling waves on the lines, and differ from the fault current shapes in typical HVDC breakertest circuits. Furthermore, the active resonant breaker and the ABB hybrid breaker perform similarly inthe used benchmarks due to the very fast DC line fault detection. |
