考虑故障阻抗与多级变压器影响的电压凹陷评估

综合考虑了故障阻抗的随机性和不同绕组联接方式的多级变压器对凹陷评估的影响。建立了故障阻抗的随机分布模型和多级变压器的等效移相矩阵,对考虑2个方面影响因素后的电压凹陷幅值与频次评估的数学模型、算法和步骤进行了详细研究。对简单9节点系统和IEEE30节点系统进行了仿真分析,结果证明,变压器绕组联接方式对电压凹陷幅值和频次均有影响,故障阻抗对电压凹陷幅值有明显影响,与现有评估方法进行比较,评估结果准确,原理简单,适用于任意规模与结构形式的电网。

Voltage sag assessment considering fault impedance and cascaded transformers

The influences of the fault impedance randomicity and the cascaded transformers with different connection modes on the voltage sag assessment are studied. The stochastic probability model of fault impedance and the equivalent phase shift matrix of cascaded transformers are proposed. The mathematic models,arithmetic and approaches of voltage sag magnitude and frequency assessment are researched with the consideration of both influences. Simulative analysis is carried out for 9-node network and IEEE-30 test s...