高压直流输电开路试验机理分析及解析计算

高压直流开路试验(Open Line Test, OLT)是检测换流阀、直流场设备、直流输电线路绝缘是否正常的重要手段。基于电力电子理论和电路理论,采用高压直流工程中换流阀实际运行参数及其触发控制方式,对高压直流开路试验建立可定量计算的等效电路。分别对带和不带直流线路开路试验的试验原理及开路电压建立过程进行解析分析和定量计算,解释了两种工况下开路电压建立的原理与物理本质。采用等效电路定量计算不同工况下开路试验电压,计算结果相比于传统公式误差显著降低。在PSCAD/EMTDC中利用CIGRE高压直流标准测试模型,对计算结果进行了仿真验证。

Mechanism analysis and analytical calculation of open line test for HVDC transmission

HVDC transmission Open Line Test (OLT) is the normal operation of an important means to detect the converter valves, DC equipment, and DC transmission line insulation. In this paper, the equivalent circuit for quantitative calculation of HVDC OLT is established based on the theory of power electronics and circuit theory and combined with the actual operating parameters and trigger control mode of converter valve in HVDC project. This paper analyzes and calculates the test principle with and without DC line OLT respectively and the process of establishing the open line voltage, and explains the principle and physical essence of establishing open line voltage under the two conditions. On this basis, the equivalent circuit is used to calculate the voltage of OLT under different conditions. The calculation results are more accurate than the traditional formula. The CIGRE simulation model of HVDC system is built by using PSCAD/EMTDC simulation software, and the simulation results are analyzed and verified. This work is supported by National Natural Science Foundation of China (No. 51777079), Smart Grid Joint Fund of State Grid Corporation of China (No. U1766213), and Science and Technology Project of China Southern Power Grid (No. ZBKJXM20180104).