The Arrester Protection Study for Valve Side of Highest Potential Converter Transformer in ± 800kV UHVDC Project

There are some characteristics for the arrangement schemes of surge arrester for ± 800 kV UHVDC transmission line converter station. One of them is that some additional arresters have been introduced to limit over-voltage further at several special locations within the converter station, including an A2 arrester which protects the valve side of highest potential converter transformer in ± 800 kV UHVDC project converter station. Aiming to Yunnan-Guangdong ± 800 kV UHVDC project, mainly the analysis and studies concentrating on the necessity of A2 arrester has been performed in this paper. Some typical fault cases have been chosen to calculate the over-voltage generated at the relative positions of converter station under with and without A2 arrester respectively. The results show that the scheme with A2 arrester can protect directly the valve-side of the converter transformer at the highest potential and reduces the insulation level of valve-side equipment effectively, which results in the production costs and manufacture difficulties will be reduced, and therefore this scheme is quite intuitive and reassuring [2].