【摘要】 模块化多电平换流器型高压直流(MMC-HVDC)输电系统接入电网后将对交流系统短路电流产生影响,但目前交流保护整定计算通常忽略MMC-HVDC接入母线故障时模块化多电平换流器对短路电流的贡献。文中以交流保护整定计算为出发点,提出了MMC-HVDC系统简化分析原则。在分析MMC-HVDC系统控制特性的基础上,建立了适用于交流保护整定计算的MMC-HVDC等效模型,提出MMC-HVDC接入母线故障时可以将直流侧等效为一个正序电流源。研究了MMC-HVDC接入母线故障时不同故障点残压下MMC-HVDC直流侧响应特性,确定了等效电流源的幅值和相位,并进行了仿真验证。最后,提出了MMC-HVDC对交流保护整定计算影响的定量评估指标及其计算方法。更多还原

【Abstract】 Short-circuit current of AC system can be affected by modular multilevel converter based high-voltage direct current(MMC-HVDC) transmission systems integrated into power grid. However, the short-circuit current contributed by the MMC has not been taken into consideration for AC protection setting calculations. From the standpoint of AC protection setting calculation, the principles of simplified analysis of MMC-HVDC are proposed. Based on the analysis of the control characteristics of MMC-HVDC system, an equivalent model of MMC-HVDC for AC protection setting calculation is established. A positive sequence current source is proposed for representing the MMC with access bus faults. Response characteristics of MMC-HVDC on the DC side with different residual voltages of fault points are studied under access bus faults for MMC-HVDC. The magnitude and phase of equivalent current source are determined and verified by simulation. Finally, a quantitative index for evaluating the influence of MMC-HVDC on AC protection setting calculation is proposed.更多还原