在太陽能并網發電系統中，如何有效、及時、準確的檢測并抑制孤島效應對于整個并網系統的安全、可靠運行具有重要的意義。本文詳細分析了傳統有源頻率擾動法在孤島效應發生時，在不同負載特性下并網逆變器輸出頻率的變化特點和不足。在此基礎上，提出了一種新的周期性正反饋有源頻率擾動孤島檢測法。在該檢測方法控制下，當電網出現故障時，在各種輸出負載特性下，并網逆變器的輸出頻率都存在較明顯的變化，因此能較容易的檢測出孤島效應，減小了系統的檢測盲區，提高了并網系統的可靠性。仿真和試驗結果表明該檢測方法能快速、準確的在不同負載下檢測出電網故障。
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.
關鍵詞﹕光伏并網發電；孤島檢測；周期性正反饋有源頻率擾動
Keywords: Photovoltaic grid-connected, Anti-islanding, AFDPDPF