基于电阻性差流的差动保护新原理

差动保护原理已经广泛应用于高压线路保护,但受电容电流的影响,全电流差动保护的抗过渡电阻能力低。文中提出基于电阻性差流分量的差动保护新原理,利用差电流的电阻性分量来构成差动保护判据,可以避免电容电流的影响。该原理与线路电容参数及电抗器补偿情况无关,对于高阻接地故障的灵敏度高,可以作为现有差动保护原理的补充。EMTP仿真验证了基于该差动保护新原理所构成的保护判据的可靠性和灵敏性。

New Principle of Differential Protection Based on the Resistance Component of Differential Current

The differential protection principle has been adopted extensively by relay protections of high-voltage transmission lines.But because of the influence of the capacitance current,the sensitivity of the full current differential relay is low under the high resistance ground fault.This paper presents a novel differential protection principle,in which the operator component of the differential protection criterion is the resistance component of the differential current.For the high resistance ground fault,the sensitivity of the presented criterion is high because its operation isn't influenced by the capacitance current and shunt reactor compensation.As a complement to the differential protection criterion,the presented criterion can be combined with the full current differential protection criterion to enhance the operational reliability of the differential relay for the metal contact ground fault as well as low and high resistance ground fault.EMTP simulation results demonstrate the high sensitivity and reliability of the presented criterion.