Single-phase adaptive reclosure based on reactive power of sequence components

This paper proposed an method for single-phase adaptive resclosure based on the reactive power of sequence components for extra high voltage (EHV) transmission lines without shunt reactors. After circuit breaker tripping the fault phase line, for the permanent fault, the voltages and currents of the fault line rapidly get into the steady state, and the reactive power of sequences components becomes almost a constant. However, in the secondary arc stage of transient fault, affected by the arc elongation, the arc voltage and the fault phase voltage increase. Therefore the positive sequence and negative sequence components of the reactive power continue to vary on the contrary way. According to this phenomenon, The rate of variation of positive sequence and negative sequence reactive power components at the faulted line side is used to distinguish fault nature. In the moment of arc extinction, the angle of the faulted phase voltage lags 90°, and then the positive sequence and negative sequence reactive powers have different polarity transitions. According to these phenomena, a new approach based on the reactive power of sequence components is used to identify the fault nature and capture the arc extinction time of the transient fault. The method is simple, hardly influenced by fault resistance and fault distance, and can be utilized in heavy load lines. EMTP simulations have verified its correctness and effectiveness. © 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved.