母线采样值差动保护数据窗选取方法研究

Research of Data Window Selection for Busbar Current Sampled Value Differential Protection

采样值差动保护动作行为的正确性取决于数据窗选取的准确性。文中基于电流互感器(current transformer,CT)的磁滞特性,分别对母差区内外故障情况下制动电流与差动电流瞬时值和变化率的特征进行分析,在此基础上,提出一种应用于母线采样值差动保护的数据窗选取方法:首先选取数据窗特征点,再由数据窗特征点倒推数据窗起始点,并进行了实时数字仿真(real time digital simulation,RTDS)验证。本采样值差动保护原理不受系统频率、电流非周期分量及CT传变特性等影响,在区外转区内复杂故障情况下,依然可以保证差动保护动作的快速性和可靠性,数据窗选取方法精准可靠,提高了采样值差动保护动作的灵敏性。

The correctness of the sampled value differential protection behavior depends on the accuracy of the data windowselection. Based on the hysteresis characteristics of the current transformer （CT）,this paper analyzes instantaneous value andthe rate of change of restraint current and differential current under the situation of busbar internal and external faults,and putsforward a data window selection method for sampled value differential protection：first select feather point of data window,thenby the feather point to push down the starting point of data window,and RTDS test is carried out to verification the principle.The sampled value differential protection principle is not affected by the system frequency,the nonperiodic current and CTtransfer characteristics and so on,and it can still guarantee the reliability and rapidity in the complex fault condition,datawindow selection method is accurate and reliable,improves the sensitivity of sampled value differential protection action.