【摘要】 分析并指出了电平检测方案存在的灵敏度不足的问题。简单介绍了利用保护测量电流、电压计算保护安装处至串补电容之间沿线各点电压的方法,并分别分析了在串补电容前和串补电容后故障以此方法所计算得到的沿线各点电压幅值的特点。在电容前金属性故障时,保护安装处至电容之间将出现电压极小值点,且电压幅值理论上为0;在电容后故障时,计算电压即使出现极值点其幅值也较高。据此提出了串补线路故障点位置识别的方法,结合传统距离保护形成了适用于串补线路的距离保护新方案。该方案能在可靠防止超越的基础上很大程度地提高距离保护的灵敏度。EMTP仿真验证了该方案的有效性和可靠性。更多还原

【Abstract】 The analysis shows that sensitivity of voltage-detected program for the existing line distance protection of series compensation is insufficient.Based on uniform transmission line positive and negative traveling wave equation,the along line voltage calculating formula is derived with the measuring current and voltage.The characteristics of calculating along line voltage is analyzed separately for fault point before and after the compensated capacitors.The calculating along line voltage will appear minimum amplitude points if the fault point is before compensation capacitor,and the minimum voltage amplitude is zero in theory.If the fault point is after compensation capacitor,the calculating voltage even having minimum,but its amplitude is a bit higher.According to the characteristics,a method for identifying the point of fault is derived,integrating it with the traditional distance protection,a new series compensated line distance protection program is proposed.The program can solve distance protection overreach problem and improve the sensitivity of distance protection for series compensated line.When series compensation capacitors installed on the end of line the sensitivity will not be impacted by series compensation capacitors.EMTP simulation results show the effectiveness and reliability of the program.更多还原