考虑分布式电源接入的配电网电流保护配置及整定方案

Overcurrent Protection Configuration and Setting Scheme for Distribution Network Considering Distributed Generation Supply Access

分布式电源的故障电流具有非线性、间歇性的特点,给配电网中的传统三段式电流保护的整定与配合带来了挑战。针对该问题,文中分析了逆变型分布式电源的控制策略及故障特征,并结合正序故障附加网络提出了一种适用于含分布式电源配电网的电流保护整定方案。该方案利用自适应保护的思想设计了正序电流速断主保护,两侧过流继电器分别作为对侧末端故障时的近后备保护;最后,由定时限过电流保护作为全线路的远后备保护。基于PSCAD的仿真验证表明,所提方案在发生不同类型、不同位置的故障时均能可靠、准确地识别故障。

The fault current of distributed generation is non-linear and intermittent,which brings challenges to the setting and coordination of the traditional three-stage overcurrent protection in distribution networks.Aiming at this problem,the control strategy and fault characteristics of inverter-ubased distributed generation are analyzed,and combined with the positive sequence fault additional network,an overcurrent protection setting scheme suitable for the distribution networks with distributed generation is proposed.The scheme firstly uses the idea of adaptive protection to design the main protection setting method,and then the overcurrent relays on both sides are used as the near back-up protection for the faults occurring near the other terminal,and finally the definite time overcurrent protection is used as the far back-up protection for the entire line.Simulation results based on PSCAD show that the proposed scheme can reliably and accurately identify the faults with different types and locations.