光伏并网系统的无盲区孤岛检测实现

IEEE Std,929-2000标准要求光伏并网逆变器必须配置孤岛保护。提出了易于DSP实现的Sandia频移(SFS)孤岛检测方案,通过分析数学模型得到一般工况下孤岛检测的不稳定判据,通过合理设计频移系数,即可实现光伏并网系统的无盲区孤岛检测。前级直流变换环节通过改进的变步长扰动追踪光伏发电系统的最大功率点可有效减少功率波动,为网侧孤岛测试提供一个良好的实验平台,进而获得理想的频移系数。仿真和实验结果均表明所提出的SFS孤岛检测的方案能快速进行孤岛保护,且对电网无污染。

Implementation of a Photovoltaic Grid-connected System With No Non-detection Zone

PV grid-connected inverter must be installed with islanding protection,according to criterion in IEEE Std. 929-2000.Sandia frequency shift(SFS) method of islanding detection implemented easily by DSP is proposed.An instability criterion can be got under the general load through its mathematical analysis model and islanding detection with no non-detection zone can be achieved in photovoltaic system if frequency shift parameter is designed rationally. Maximum power point tracking(MPPT) is implemented in the DC converter by the improved variable step-size method, which can reduce power fluctuations effectively and can provide a good test platform for islanding protection in the grid-side to obtain the ideal value.Both simulation and experimental results show that SFS islanding detection method can achieve islanding protection quickly and pollution-free to the power grid.