基于电流行波极性的高压直流极母线保护

摘要

Large transient unbalance current may occur on the HVDC pole bus-bar differential protection when an internal fault hits, which causes the malfunction of the protection system. This paper presents the working principle of the protection of HVDC pole bus-bar based on the polar of initial current traveling waves, and this protection can entirely eliminate all the differential protection malfunctions caused by the unbalanced current as it can identify the internal fault and extemal fault of the pole bus-bar through polarity of the initial current traveling waves. The theoretical analysis suggests the protection method enjoys fast operation speed, high sensitivity and reliability with simple patterns. The PSCAD simulation proves effectiveness of this protection.%高压直流极母线的差动保护在外部故障时可能出现较大的暂态不平衡电流,从而引起保护误动.分析了基于故障时电流行波极性的极母线保护原理,通过判断行波极性区分母线的区内区外故障,能从根本上解决因不平衡电流引起的保护误动问题.理论分析表明,利用电流行波实现的母线保护具有动作速度快,灵敏度高和简单可靠等特点.PSCAD/EMTDC仿真验证了该方案的有效性.