±800kV云广DC换流站避雷器布置和参数选择

Arrester Protection Scheme and Arrester Parameters Selection for ±800 kV YunGuang UHV DC Converter Station

±800kV换流站的过电压保护主要采用无间隙的氧化性避雷器。为了优化和合理地确定±800kV云广直流输电工程换流站避雷器布置方案和选择参数,介绍了云广直流输电工程换流站400kV高端12脉动换流单元的换流变压器阀侧过电压保护避雷器布置的2种方案,方案Ⅰ采用A2和CB1A避雷器,方案Ⅱ采用M2和CB1A、CB1B避雷器。比较了2种方案的优缺点后推荐采用方案Ⅰ。分析了装C2避雷器保护高端400kV换流单元的必要性后提出换流站A2、CB1A和M2等避雷器选择直流参考电压的原则和并选择了它们的参数。分析了平波电抗器分置在中性母线和极线方式降低A2避雷器的直流参考电压,从而降低高端800kV换流变压器操作冲击绝缘水平的作用。所选择的避雷器的布置方案和避雷器的参数已在云广直流输电工程中得到应用。

The MOA arresters are used as a main overvoltage protection device for ±800 kV converter station. In order to optimized and reasonably determine the attesters arrangement and select the arresters parameters, this paper introduces the two attester protection schemes to protect converter transformers valve side of up 12 pulse converter unit for ±800 kV YunGuang UHV DC converter station. The scheme Ⅰ uses A2 and CBIA type arresters and the scheme Ⅱ uses M2, CBIA, CB1B type arresters. The advantages and disadvantages of the two schemes were pointed out and the scheme 1 is recommended. The necessity of installing C2 arrester to protect up 12 pulse converter unit is analyzed. The A2, CB1A and M2 etc various arrester parameters selection methods and principles are presented, as well as the selected arrester parameters for converter station. The effect of the reducing A2 arrester DC reference voltage is analyzed with the arrangement that smooth reactor is equally installed on neutral bus and pole bus, consequently, to reduce up 12 pulse converter transformer switching impulse insulation level. The selected arrester protection schemes, the arrester arrangement and parameters are used in gunGuang UHV DC converter station.