中文摘要：

针对传统纵联保护的不足,提出了一种基于故障分量虚拟阻抗的线路差动保护原理。考虑分布参数的影响,利用线路两端故障分量推导线路中任意点处的电压、电流故障序分量,并将二者之比定义为虚拟阻抗。取线路中点处各序的电流故障分量和虚拟阻抗构成保护判据,识别各种类型的故障。仿真结果表明,该判据能准确识别各种类型的故障,灵敏度和可靠性较高,且不受故障位置、过渡电阻、负荷电流、分布电容及信息同步的影响。

英文摘要：

A kind of differential protection principle based on the virtual impedance of faulty component is proposed ,which ,with the consideration of distributed parameters ,applies the fault sequence components of both line ends to deduce the fault sequence components of voltage/current at any point of that transmission line and defines the ratio of voltage fault sequence component over current fault sequence component as the virtual impedance. The virtual impedance and current fault sequence component of the middle point are used to compose the protection criteria for each sequence respectively. Simulative results show that, immune to the fault location, transition resistance, load current, distributed capacitance and information synchronization, the proposed criteria can identify different kinds of fault more sensitively and reliably.