含分布式电源的配电网方向过流保护

含分布式电源的配电网对继电保护装置的动作速度和保护范围提出了更高的要求。文章基于配电网电流正序分量相位的变化，提出一种方向过流保护方案，该方案首先利用故障前一周期和故障后一周期的电流正序分量相角差判定故障方向，然后通过比较三相电流绝对值间隔0.01 s差分后的最大值和最小值之差来判断故障相别。推导了故障方向判据，以10 kV馈线方向保护为例，说明了该保护方案的可靠性和灵敏度，并在双回配电系统中验证了该方案的有效性。

Directional Overcurrent Protection for Distribution Systems Containing Distributed Generation

The distribution network containing distributed generation (DG) raise a higher demand to both action speed and protective range of protective devices. Based on the phase variation of positive-sequence component of current in distribution network, a directional over-current protection scheme is proposed. In this scheme, firstly by use of phase angle difference of positive-sequence component of current in one period just before the fault and that just after the fault, the fault direction can be determined; then the faulty phase is judged by comparing the difference between the maximum and the minimum of differentiated value of absolute value of three-phase current with interval of 0.01s; thus the fault direction criterion is deduced. Taking the directional protection of 10kV feeder for example, the reliability and sensitivity of the proposed protection scheme is illustrated. The effectiveness of this protection scheme is validated by double-circuit distribution system.