A new solid-state HVDC circuit breaker topology for offshore wind farms

This paper presents a new topology for solid-state HVDC circuit breakers which does not require MOV for fault energy absorption. Due to its simple yet robust design, it offers a reliable and cost effective solution for isolating faults in HVDC lines connecting remote generating stations to the grid. Since the proposed design does not contain a mechanical breaker or a metal-oxide varistor (MOV), problems resulting from wear and tear of moving parts, arc faults, and degradation or catastrophic failure of surge arrestors are entirely eliminated. This design has inherently a very fast response and is particularly suitable for voltage source converters that are vulnerable against dc faults. To verify the performance and dependability of the proposed circuit breaker, a computer simulation has been developed to handle faults occurring at a 300 kV submarine transmission line that connects a typical 250 MW offshore wind farm to the grid.