串并联水冷系统对换流阀均压特性影响研究

Research on the Influence of Series and Parallel Water Cooling System on the Voltage Equalization Characteristics of Converter Valves

换流阀水电阻为兆欧级别,与阀组件直流均压电阻值近似,水路布置方式改变换流阀的阻抗网络,从而影响均压特性。首先根据换流阀水路设计方案、阀塔结构布局计算换流阀的阻抗参数,然后基于PSCAD搭建换流阀阻抗等效模型,仿真分析在不同工况下换流阀的均压情况,最后开展试验验证。结果表明:水路结构改变了换流阀阻抗网络,对交流和冲击电压分布影响较小,对直流电压分布影响最大。单阀直流耐压试验工况组件最大不均压度为4.4%,单阀冲击电压工况组件最大不均压度2%,子模块电压都在器件的耐受范围内。型式试验结果表明组件的电压分布及绝缘设计均满足要求。

The water resistance of the converter valve is MQ level,which is similar to the DC voltage equalization re-sistance of the valve component.The way of waterpipe layout changes the impedance network of the converter valve,thereby affecting the voltage equalization characteristics.Firstly,the impedance parameters of the converter valve are calculated based on the waterway design scheme and valve tower structur.Then,an equivalent impedance model of the converter valve is built based on PSCAD,and the voltage equalization of the converter valve under different conditions are simulated.Finally,experimental verification is carried out.The results indicate that,the waterway has changed the impedance network of the converter valve,with less impact on the distribution of AC and impulse voltage,and the greater impact on the distribution of DC voltage.The maximum uneven voltage of the component is 4.4%under the DC withstand voltage test condition of single valve,and is 2%under single valve impulse voltage.The voltage of the sub modules is within the tolerance range of the device.The type test results indicate that the voltage distribution and insulation design of the components meet the requirements.