适用于带并联电抗器输电线路的电流模型识别纵联保护新原理

Pilot protection principle based on current model recognition applicable to transmission line with shunt reactors

针对两端带并联电抗器的输电线路,提出了一种基于电流模型识别的纵联保护新原理。首先采用线路分布参数模型,推导出发生区外故障时两侧电流和差比值的理论表达式,将其作为待识别的基准模型。接着构造区外故障模型误差函数用于描述实际故障数据与基准模型的符合程度。区外故障时,模型误差函数等于零;区内故障时,模型误差函数不为零,据此区分外部和内部故障。该原理考虑输电线路带并联电抗器的情况,不受分布电容影响,无需补偿电容电流;充分利用故障电流信息,不引入电压量;能够可靠、灵敏、快速地动作。ATP仿真和动模仿真结果验证了新原理的有效性。

A novel pilot protection principle based on transmission line with shunt reactors on both sides. The distributed parameter model of transmission line and taken current model recognition is proposed for the theoretical expression is derived based on the as the benchmark model of out-zone fault,which describes the ratio of the sum of to the difference between the fault currents at both line sides. The model error function of out-zone fault is then constructed to gauge the coincidence degree of the fault data with the benchmark model. The value of model error function is zero for out-zone faults while non-zero for in- zone faults,which can be used to distinguish out-zone fault from in-zone faults. As the shunt reactors are considered,the proposed principle is immune to the distributed capacitance and no capacitive current should be compensated. Since the protection uses fully the fault current information, without the voltage measurement,it functions reliably,quickly and sensitively. Both ATP simulation and dynamic simulation results show the effectiveness of the proposed principle.