基于序分量无功功率的单相自适应重合闸

针对不带并联电抗器的超高压输电线路,提出一种基于序分量无功功率的单相自适应重合闸实现方法。当线路发生单相接地故障且故障相两端断路器跳开后,在永久性故障下,线路侧各相电压和电流值经短暂时间过渡到稳态,之后各序分量无功功率基本保持恒定;在瞬时性故障二次电弧尚未熄弧阶段,电弧电压和故障相端电压随电弧拉长不断升高,正序无功与负序无功呈现相反方向的增减变化。基于这一现象,采用线路侧断开处的正序与负序无功功率分量的变化率来区别永久性和瞬时性故障。在二次电弧熄弧瞬间,故障相电压相位会后移90°,此时正序与负序无功功率分别有不同极性的跃变,通过检测序分量无功功率的突变来捕捉熄弧时刻。该方法实现简单,耐过渡电阻能力强,受故障位置影响小,能适用于重负载线路。EMTP仿真验证了其正确性和有效性。

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 90o,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.