| 摘要 |
A VSC-converter for converting direct voltage into alternating voltage and vice versa, comprising several current valves (1; 10-13), each current valve comprising a semiconductor element (2) of turn-off type and a first rectifying member (3) connected in anti-parallel therewith. At least one of the current valves is provided with a circuit for over voltage protecting connected in parallel with the current valve, which circuit comprises a series connection of a surge arrester (5) and a second rectifying member (6), the second rectifying member (6) being connected in anti parallel with the first rectifying member (6) being connected in anti parallel with the first rectifying member (3) included in said at least one current valve. The invention also relates to a VSC-converter where each of the series connected circuits (30) that build up the current valves of the converter comprises, in at least one of the current valves, a surge arrester (5) connected in parallel with a capacitor (33) included in the circuit (30) and in series with a rectifying component (34) included in the circuit (30). |
