微电网供电系统孤岛问题优化检测仿真

摘要

For the safety of equipment and personnel,microgrid power supply system needs to have the function of detecting islanding in time.By analyzing the mechanism of traditional slip-mode frequency shift method,for the problems of long detection time in slip-mode frequency shift method and greater impact on system power quality in DSP application environment,an improved algorithm was proposed in the paper.Since the slope of the improved algorithm's phase-shifting curve is infinite at peak,the frequency of the voltage at the point of common rapidly deviates from the grid frequency after islanding.In addition,the improved algorithm adjusts the positive feedback of perturbation phase to achieve the purpose of rapid detection of islanding by detecting the variation of frequency.The improved algorithm under certain load conditions does not have detection blind spots,and it has low impact on system power quality.Simulation results verify the validity of the improved algorithm.%为了设备和人员的安全,微电网供电系统必须具有及时检测出孤岛的功能.通过对传统的孤岛检测方法滑模频率偏移法(Slip-Mode Frequency Shift,SMS)的工作机理和电网失压后公共点电压的频率偏移轨迹进行分析,针对SMS算法在DSP应用环境下检测时间较长,对系统电能质量影响较大等问题,提出了一种改进算法.改进算法的相位偏移曲线在顶点处的斜率为无穷大,使得孤岛发生后公共点电压的频率快速偏离电网频率.利用改进算法检测频率变化调节扰动相位的正反馈,从而快速检测出孤岛.改进算法在一定负载条件下不存在检测盲区,对系统电能质量影响较低.仿真结果表明改进算法的正确性.