周期性正反馈有源频率扰动法在光伏并网系统中孤岛检测的应用

在太阳能并网发电系统中，如何有效、及时、准确的检测并抑制孤岛效应对于整个并网系统的安全、可靠运行具有重要的意义。本文详细分析了传统有源频率扰动法在孤岛效应发生时，在不同负载特性下并网逆变器输出频率的变化特点和不足。在此基础上，提出了一种新的周期性正反馈有源频率扰动孤岛检测法。在该检测方法控制下，当电网出现故障时，在各种输出负载特性下，并网逆变器的输出频率都存在较明显的变化，因此能较容易的检测出孤岛效应，减小了系统的检测盲区，提高了并网系统的可靠性。仿真和试验结果表明该检测方法能快速、准确的在不同负载下检测出电网故障。
Abstract: Anti-islanding is a major issue in photovoltaic grid-connected system. The disadvantages of the conventional active frequency drift (AFD) method in various load conditions are analyzed for islanding prevention. A novel active frequency drift method with periodic disturbance and positive feedback (AFDPDPF) is proposed in this paper to reduce the non-detection zone (NDZ) and increase the speed of anti-islanding detection compared with the conventional AFD. The system reliability is improved by the proposed method. The simulated and experimental results verify the effectiveness of the proposed anti-islanding method.
关键词﹕光伏并网发电；孤岛检测；周期性正反馈有源频率扰动
Keywords: Photovoltaic grid-connected, Anti-islanding, AFDPDPF