正反馈孤岛检测方法对基于逆变器的分布式发电系统稳定性的影响

Influence of positive feedback anti-islanding scheme on inverter-based distributed generator stability

研究了频率正反馈孤岛检测方法对基于逆变器的分布式并网发电系统稳定性的影响。通过建立分布式发电系统的模型,进而得出分析系统稳定性的小信号模型,以分布式电源输出功率作为系统稳定性指标,利用分布式电源输出功率与孤岛检测正反馈增益之间的关系曲线作为工具进行稳定性分析。分析结果表明,正反馈方法对系统稳定性有消极作用,且正反馈增益越大,系统越不稳定。并对影响分布式并网发电系统稳定性的重要参数进行灵敏度分析;最后通过仿真验证了理论分析结果。

This paper investigates the influence of positive feedback anti-islanding scheme on inverter-based distributed generator stability. The distributed generation system model is established, by which the small signal model for analyzing system stability is obtained. The output power of distributed generation is taken as system stability index and the relationship curve of distributed generation output power and positive feedback gain of islanding detection is used as a tool for stability analysis. The results show that the positive feedback anti-islanding scheme does have the potential to destabilize the DG system. If the positive feedback gain is too high, the DG system will become unstable. Sensitivity studies of important parameters are conducted for DGs. Finally, the simulation results verify the theoretical analysis result. This work is supported by the National Natural Science Foundation of China （No. 51007044） and State Key Laboratory of Power Transmission Equipment ＆ System Security and New Technology （No. 2007DA10512709407）.