一种基于电流自构参考量的电流方向纵联保护

基于零序方向或者负序方向构成的保护在电力系统继电保护中占重要地位，但当系统经高阻接地或PT断线时，一些测量点的序电压很小，进而影响方向元件的判别。为解决上述问题，提出一种仅利用测量电流本身(如零序电流或者负序电流)自构建零序或者负序的参考量值，基于测量电流与参考量的比较结果转换为状态量，进一步由线路两端方向状态比较构成保护判据。在系统发生不对称故障后，利用故障零/负序电流的微分、反向等数据综合处理，获取送受端方向一致的电流参考量，再基于测量零/负序电流与参考量的比较构建新的方向判据。该方法不需要电压信息，大大降低了保护的通信量，在高阻接地、不同故障初始角等情况下仍正确动作，可应用于广域系统。仿真结果验证了本保护判据的可靠性。

A new pilot direction protection based on self-constructing reference current

The protection based on zero sequence direction or negative sequence direction plays important roles in power system relay protection. But in the condition of a high resistance grounded system or PT disconnection, the voltage at some of measuring points is small which will affect the discrimination of directional element. In order to solve these problems, this paper brings forward a new criterion based on zero sequence current or negative sequence current to build zero sequence directional reference or negative sequence directional reference. And then a pilot directional protection is constructed by comparing two-terminal direction results of a line. After the asymmetrical faults occurs in system, it utilizes information-integrated processing of zero/negative sequence current like differential method and reverse method to acquire the current reference direction of sending side and receiving side in the same direction, building a new criterion based on the comparison of zero/negative sequence current and reference direction. This method does not need voltage information that can greatly reduce the communication traffic of the protection, and is immune to different fault initial angle and large ground resistance. Thus it can be widely used in wide-area protection system. Simulation results show that the direction criterion is reliable. This work is supported by National Natural Science Foundation of China (No. 51607106) and Key Project of Science and Technology Research Program of Hubei Provincial Education Department (No. Z2017037).