在太陽(yáng)能并網(wǎng)發(fā)電系統(tǒng)中，如何有效、及時(shí)、準(zhǔn)確的檢測(cè)并抑制孤島效應(yīng)對(duì)于整個(gè)并網(wǎng)系統(tǒng)的安全、可靠運(yùn)行具有重要的意義。本文詳細(xì)分析了傳統(tǒng)有源頻率擾動(dòng)法在孤島效應(yīng)發(fā)生時(shí)，在不同負(fù)載特性下并網(wǎng)逆變器輸出頻率的變化特點(diǎn)和不足。在此基礎(chǔ)上，提出了一種新的周期性正反饋有源頻率擾動(dòng)孤島檢測(cè)法。在該檢測(cè)方法控制下，當(dāng)電網(wǎng)出現(xiàn)故障時(shí)，在各種輸出負(fù)載特性下，并網(wǎng)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(cè)出孤島效應(yīng)，減小了系統(tǒng)的檢測(cè)盲區(qū)，提高了并網(wǎng)系統(tǒng)的可靠性。仿真和試驗(yàn)結(jié)果表明該檢測(cè)方法能快速、準(zhǔn)確的在不同負(fù)載下檢測(cè)出電網(wǎng)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(guān)鍵詞﹕光伏并網(wǎng)發(fā)電；孤島檢測(cè)；周期性正反饋有源頻率擾動(dòng)
Keywords: Photovoltaic grid-connected, Anti-islanding, AFDPDPF