基于模型识别光伏接入配电网线路纵联保护研究

光伏因受外界环境因素影响，输出功率存在间歇性和波动性。分布式光伏系统接入配电网会导致部分线路电流保护误动、拒动和灵敏度下降问题。在分析分布式光伏接入配电网故障特征的基础上，基于参数辨识理论对模型识别纵联保护原理进行改进与优化，提出光伏接入配电网线路保护判据。改进后的模型识别纵联保护方法将线路区外、区内故障均等效为不同的电感电路模型，根据线路故障时内、外部模型误差大小来区分区内、区外故障。通过PSACD/EMTDC仿真验证，该方法有效克服了光伏接入配电网分支电流的影响并且能够快速、准确地动作，从而验证了将模型识别纵联保护原理应用在光伏接入配电网线路保护的正确性和有效性。

Photovoltaic access to distribution network line pilot protection based on model identification

Photovoltaic power generation is intermittent and fluctuating due to external environmental factors. It will cause the current part of the line protection malfunction and failure to trip and sensitivity decrease when distributed PV system connected to distribution network. Model identification pilot protection principle is improved and optimized based on fault feature of analyzing distributed PV connected to distribution network. Thus the PV connected to the distribution network protection criterion is proposed. In the improved model identification pilot protection method, both the external zone fault and internal zone fault are equivalent to different inductor circuit models; and internal and external faults can be distinguished based on the error values of internal and external model when line is fault. PSACD/EMTDC simulation verifies that the method effectively overcomes the influence of branch current of photovoltaic accessing to distribution network, and can quickly cut off the fault, which validates the correctness and effectiveness of the model identification pilot protection principle used in photovoltaic grid connected.