主动频率漂移法孤岛效应检测分析与优化

Analysis and optimization of active frequency drift method for islanding detection

采用间歇性扰动和加大频率扰动周期的方法提高并网逆变器主动频率偏移法孤岛效应检测的性能,减小其检测盲区.在间歇性扰动方法中,插入不施加扰动的时段,孤岛效应情况下该时段内系统工作频率为负载的谐振频率,根据谐振频率来确定扰动的方向,可获得相应扰动幅度下最小的检测盲区;加大频率扰动周期的方法可以相对较小的频率扰动幅度,在保证电流波形质量基础上进一步提高孤岛效应检测的性能.

Two methods, the intermittent frequency drift and the increase of the period of frequency disturbance, were employed to raise the islanding dection performance of active frequency drift methods for grid-connected inverters and to reduce the non-detection zone of traditional active frequency drift methods. As for the intermittent frequency drift method, a no-disturbing interval was inserted into the continous disturbing process. The operating frequency during this interval was the resonant frequency of the resonant load. The system decided the disturbing direction based on the sampled resonant frequencies of the load, and the non-detection zone might be minimized under the corresponding distubing steps. The method of increase of the period of frequency disturbance might improve the islanding detection performance with smaller frequency distubing steps based on the guarantee of quality of current waveform.