论文部分内容阅读
电力系统中的潮流转移会引起线路事故过负荷及其距离Ⅲ段保护误动作，这是导致连锁跳闸，最终发生大停电事故的重要因素之一。为此，利用广域测量系统(wide area measurement system，WAMS)的优势，提出一种潮流转移识别方案。根据三相电流增量及零序电流的大小来区分线路过负荷和不对称短路故障，根据电压幅值的大小来区分线路过负荷和对称短路故障，并提出了相应的识别判据。考虑到系统振荡对判据判断的影响和故障切除后过负荷发生的情况，提出了具体的潮流转移识别策略，并给出了实现流程，该策略可有效防止距离Ⅲ段元件在事故过负荷时误动，并能保证在故障时可靠开放距离Ⅲ段保护。通过对新英格兰10机39节点系统进行仿真，验证了该方法的有效性。“,”In the power system, power flow transfer can cause emergency overload or the maloperation of zone Ⅲdistance relays, and this is one of the main factors causing cascading trips and eventual blackout. Taking advantages of wide area measurement system (WAMS), the paper proposed a power flow transfer identification scheme. According to the differences of three-phase current increments and zero-sequence current, asymmetric faults on transmission lines and overload can be distinguished. According to the voltage amplitude, symmetric faults and overload can be distinguished. And corresponding identification criterions were given. Taking into account the effect of system oscillation and the overload condition after faults, the practical strategies of power flow transfer identification was proposed and its implementation process was given. The strategy can effectively prevent zoneⅢ distance protection from maloperation for overload conditions and reliably unblock it for faults. Through the simulation of New England 10-machine 39-bus system, the effectiveness of the proposed scheme was verified.