电力系统自动化2019，Vol.43Issue(5)：107-113,7.DOI:10.7500/AEPS20180721001
柔性直流电网重合闸过电流和过电压抑制
Suppression of Reclosing Overcurrent and Overvoltage of Flexible DC Grid
摘要
Abstract
Temporary faults often occur on overhead transmission lines of flexible DC grid, so reclosing scheme is the key measurment to inprove the reliability of power supply. However, reclosing may result in overcurrent and overvoltage again, and thus influence the safe operation of the system. A simple and effective calculation of the reclosing current limiting resistance is first proposed. The constraint relation between the arm current and current limiting resistance is established by estimating the maximum arm current, so the overcurrent in the bridge arm of the converter can be limited to a reasonable level and the converter blocking time can be avoided during reclosing. Then, the cause of overvoltage across the converter is analyzed, and a novel voltage limiting circuit, which composed of a thyristor and energy absorption resistance is proposed, which is in parallel with the arm reactor and can provide additional current path for arm reactor when the DC circuit breaker trips. Consequently, the transient overvoltage of the system can be prevented effectively. At last, a three-terminal DC test system with ring topology is modeled in PSCAD software, and a large number of simulation results verify the effectiveness of the proposed method.关键词
柔性直流电网/架空线路/重合闸/限流电阻/限压电路Key words
flexible DC grid/overhead lines/reclosing/current limiting resistance/voltage limiting circuit引用本文复制引用
李岩,龚雁峰..柔性直流电网重合闸过电流和过电压抑制[J].电力系统自动化,2019,43(5):107-113,7.基金项目
中央高校基本科研业务费专项资金资助项目(2017XS014) （2017XS014）
This work is supported by Fundamental Research Funds for the Central Universities (No. 2017XSOI4). （No. 2017XSOI4）
