线路差动保护判别TA二次断线的新方法

微机线路差动保护具备TA断线检测的能力,在线路发生TA断线时不造成误动。而TA断线的特征又与弱馈侧高阻接地的特征很相似。提出了一种判别TA断线的新方法,该方法在确保TA断线能正确检测的前提下,又能确保弱馈高阻接地故障时不会误闭锁差动保护。RTDS试验证明该方案安全可靠。

Novel Identification Method for Secondary Circuit Disconnection of TA by Line Differential Protection

The microcomputer-based line differential protection has the ability to detect TA disconnection,and it can not cause the misoperation when TA disconnection occurs.The features of TA disconnection are similar to the characteristics of high-impedance grounding in weak feedback side.A new method for identifying TA disconnection is presented.The proposed method can ensure that the differential protection can not be blocked incorrectly when high-impedance grounding fault occurs in weak feedback side on the premise of TA disconnection being detected correctly.RTDS tests show that it is a safe and reliable scheme.