一种线路高频保护防误方法分析及措施研究

摘要:

提出了由于电网结构差异较大，负荷结构和电源布局不均匀导致线路区外对称故障时可能出现较大的零序电流，进而导致线路高频保护误动作的思考。理论推导了对称故障下出现零序电流的原因，在此基础上搭建了仿真模型进行仿真。理论分析和仿真结果表明线路系统区外对称故障下零序电流的最大确实会导致被保护线路高频保护误动。以新疆某地区实际电网为模型，沿用系统参数设置，采用在线和离线的方法调节系统负荷及电源投入情况，模拟并分析出现的高频保护误动情况，进而针对模拟情况提出合理的预防建议和措施。

Abstract:

A stronger zero － sequence current may occur when the symmetrical fault appears outside the line zone due to the different structure of power grid，uneven load structure and power distribution，which results in the misoperation of high － frequency protection． The reasons why zero － sequence current occurs under symmetrical fault are analyzed by theoretical derivation，and the simulation model is established． The theoretical analysis and simulation results show that the maximum zero － sequence current under symmetrical fault outside the line zone will exactly cause the misoperation of high － frequency protection in the protected line． Taking the actual power grid as the model in one place of Xinjiang，the misoperation of high － frequency protection is simulated and analyzed by following the setting of system parameters and adopting the on － line and off － line methods to control the system load and the power source connection，thus the reasonable preventive suggestions and measuresare put forward．