负荷对重载长线路单相短路电流的影响研究

Research on the Influence on Heavily Loaded Long Circuit Single-phase Impedance Current

基于叠加原理,给出了考虑负荷影响时重载长线路单相短路电流的计算方法.并通过实例计算,分析了忽略负荷影响与考虑负荷影响时短路电流计算值之间的误差,得出在一般情况下短路全电流的误差在15%以下,在一般工程应用中忽略负荷影响基本上是允许的.但是接地相短路电流正序分量计算值的误差则高达30%以上,这会严重影响相关继电保护及安全自动装置的合理整定.

On the basis of the principle of superposing, this paper provides the computing technology of impedance current when considering the electric current of load influences. Through the embodiment, this paper analyzes the impedance current value error between neglecting load influences and considers load influences, and draws the conclusion that the error of total leakage current is under 15% in general cases, which is basically allowed in general application of project. But the calculation error of the ground phase impedance current when neglect load influences, up to more than 30%, it will have influenced seriously the setting of protection equipment and stability control devices.