摘要
利用故障时母线上的电压相量与母线上所连各支路电流相量之和的比值,来判断母线的内、外部故障。在母线外部发生故障时,该比值反映的是母线的容抗,其幅值很大,且其相角接近-90°;内部故障时,该比值反映的是母线故障时的过渡电阻,其幅值相对较小,且相角接近0°。据此可以区分母线的内、外部故障。新原理判据在母线内、外部故障时不仅具有很好的反差特性,而且有较强的抗电流互感器(CT)饱和能力,其动作的灵敏度和可靠性不受母线高阻接地以及多角形接线或3/2断路器接线的母线内部故障有汲出电流时的影响,而且原理简单、易整定。EMTP仿真验证了新原理的有效性和可行性。
The principle uses the ratio of the voltage phasor of the bus-bar to the branch current phasor sum to detect internal faults and external faults, which is defined as the integrated impedance in this paper. The integrated impedance of an external fault reflects the capacitance impedance of the bus-bar, its amplitude is large and the phase angle is close to-90° , while the integrated impedance of an internal fault is the fault resistance, its amplitude is comparatively small and the phase angle is close to 0° . As a result, the magnitudes and arguments of the integrated impedances are quite different between an external and an internal fault. According to such a characteristic, the criterion of fault detection is put forward, which has the inherent immunity to the impact of current flowing out when a fault occurs in the protection zone of the polygon connection or breaker-and-a-half bus-bar and the effect of the CT saturation on the proposed principle is discussed. EMTP simulation results verify the sensitivity and reliability of the proposed principle.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2010年第18期1-7,共7页
Power System Protection and Control
基金
国家自然科学基金项目(50677051
50877061)
教育部博士点基金(20070698057)~~
关键词
母线保护
综合阻抗
CT饱和
3/2断路器接线
汲出电流
bus-bar protection： integrated impedance： CT saturation： breaker-and-a-half configuration： out-flowing current
