电铁微机馈线保护阻抗元件合理动作特性探讨

对电铁微机馈线保护阻抗元件动作特性进行探讨，主要围绕保护特性中的拒动及误动现象展开，并针对串补线路保护出口金属性短路存在的保护拒动，提出了一种新的包括原点的阻抗动作特性，即在多边形方向特性上叠加了一个矩形特性，这两个特性彼此独立，通过实例验证，证明在串补线路该阻抗特性可提高阻抗保护的可靠性。

Discussion on Protective Characteristic of Impedance Relay in Microprocessor-Based Feeder Protection of Electrical Railway

The discussion on protective characterstic of impedance relay in microprocessor based feeder protection of electrical railway is developed at the phenomena of its malfunction.For the protective tripping failure caused by the short circuit at protection output on the line with serial capacitor,a new characteristic,including the initial point, is proposed,i.e.A rectangular characteristic is added on the polygonal directional characteristic.The two protective characteristics are independent to each other. It is verified by test that, the new protective characteristic can improve the reliability of impedance protection on the line with serial capacitor.