基于单端信息量的特高压串补线路距离保护方案

A fault location scheme of UHV series compensated line based on one-terminal information

基于输电线路的R-L模型,提出了一种利用单端信息量的串补线路距离保护方案。该方法根据串补电容与线路参数的关系,列解故障状态网络和故障附加网络微分方程,推导出一组以故障距离和过渡电阻为待求参数的方程式,通过求解线性方程直接得到故障位置。该方法可以实现故障的精准定位,较好地解决了传统距离保护在串补线路中的暂态超越问题,同时,利用MOV导通前的暂态信息,很好的避开了MOV导通初期串补电容电压难以获取的问题,极大的提高了距离保护的可靠性。利用PSCAD仿真验证了该方案的可靠性和有效性。

This paper is based on the R-L model of transmission line, using single end data to test the fault distance, to achieve the series compensated line distance protection. This method is based on the relationship between series compensation capacitor and transmission line parameters, to solve the differential equation of the fault state network and fault components network. An equation is got with the fault distance and transition resistance as the variables. Fault location can be obtained directly by solving the linear equation. This scheme can solve transient beyond problem in tra- ditional series compensated protective scheme. At the same time, this scheme only uses the transient data before MOV, the protection can avoid nonlinear feature of MOV which makes voltage of series compensated capacitors difficult to obtain, then greatly improve the reliability of distance protection. At the end using PSCAD simulates this scheme, the results verify the validity and adaptability of the scheme.