直流换相失败整体免疫能力评估方法与应用

Study and application of overall immunity of DC commutation failure caused by AC faults

交流故障导致直流系统换相失败的免疫能力评估方法,可以为交直流混合电力系统的规划和安全稳定运行提供合理有效的决策依据。首先,采用换相失败免疫因子量化交流系统各节点的换相失败免疫能力,通过计算各交流节点允许接入的最大三相接地阻抗确定该指标值。基于此,利用PAM聚类算法辨识电网免疫能力薄弱节点。构建基于换相失败免疫因子均值和均衡程度的免疫能力整体评估指标,综合评估直流系统抵御交流故障的免疫能力。最后,模拟算例和基于某省级电网2种远期规划方案的实际算例,均验证了该文方法的优越性和有效性。

The immunity assessment of DC commutation failure caused by AC faults is helpful to provide reasonable and effective decision-making basis for the planning and safe stable operation of AC/DC hybrid power system. Firstly, the commutation failure immunity index(CFII) is employed to quantify the commutation failure immunity of each node in the AC system, and it is determined by calculating the maximum three-phase grounding impedance of each AC node. Then, the weak immune nodes of power grid is identified automatically by using PAM clustering algorithm. Next, the immune ability of DC system against AC fault is evaluated comprehensively based on the mean value and equilibrium degree of CFII. Finally, a simulation example and a practical example of two long-term planning schemes for a provincial power grid is included to verify the superiority and effectiveness of proposed method.