为了分析电流源换流器(CSC)和电压源换流器(VSC)结合而成的交流/混合多端直流混联系统的静态电压稳定性,给出了一种寻找最临近电压失稳点的方法.采用改进连续潮流法,从系统初始运行点出发,计及联结变压器电压比的调节和换流器控制方式的转变,根据最短路径原理不断修正负荷增长方向,并且采用自适应负荷增长方向的步长控制策略逐渐逼近最危险负荷增长方向,最终确定混联系统的最临近电压失稳点和最小负荷裕度.对基于IEEE14节点的交流/混合三端直流混联系统进行了仿真分析.仿真结果表明该方法是有效可行的,最临近电压失稳点能够准确反映混联系统的电压失稳情况.%For analyzing the static voltage stability of the hybrid-MTDC system which is combined by current source converter (CSC) and voltage source converter (VSC), a method to find the closest voltage instability point is proposed. Based on the algorithm of improved continuation power flow, this paper considers the transformation of the converter turns ratio and the conversion of the converter's control modes in the calculation procedure. Trace the changing direction from the initial point to the breakdown point and use the self-adaptive step control strategy, gradually approach to the most dangerous load growth direction. Calculation comes to an end until get the closest voltage instability point, meanwhile the minimum load margin is obtained. AC/Hybrid three-terminal DC system based on IEEE14 is analyzed by this method. Simulation results show that the proposed method is effective and feasible. The closest voltage instability point can accurately reflect the voltage instability.
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