串联补偿线路的距离保护研究

Study on distance protection for series-compensated lines

分析继电保护安装处的测量阻抗与线路阻抗的关系,在此基础上定义一个具有自适应特性的补偿阻抗,并分析故障点相对于串联补偿装置不同位置时补偿阻抗的相角特性,即金属性故障位于串补装置之前时,补偿阻抗的相角为0°;金属性故障位于串补装置之后时,补偿阻抗的相角介于90°和270°之间。据此提出识别串补线路故障点的方法,并与传统的电平检测方案相结合形成新的距离保护方案。该方法适用于串补装置安装于线路不同位置的运行方式,不仅可以有效解决超越动作问题,而且可提高保护的灵敏度。MATLAB仿真验证了该方法的正确性。

By the analysis of the relationship between the measured and real impedance of a line,a compensated impedance with self-adaptive characteristics was defined.The phase angles of the defined impedance were analyzed in different scenarios,in which the phase angle of the compensated impedance is 0° when a fault happens before the series capacitor and is 90～270° otherwise.Accordingly,a new fault location method was derived to form a new series-compensated line protection scheme combined with traditional level-detection methods used in distance protection.The proposed method can be applied to various operation modes with different installation locations of series compensators in a system.The method can also avoid overreach problem of distance relays and improve the sensitivity effectively.The validity and reliability of the proposed scheme were verified by the simulation on MATLAB.