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關鍵詞: 并網逆變器; 電網阻抗; 混合式孤島檢測法; 諧波注入法; 閾值設定; 被動法; 主動法
中圖分類號: TN464?34" " " " " " " " " " " " " " " 文獻標識碼: A" " " " " " " " " " "文章編號: 1004?373X(2025)04?0151?08
Method of hybrid island detection with adaptive impedance in power grid
ZHANG Chengyu1, DAI Haiping2, HUANG Yaoyao1, CAI Hui1, LI Lingzhi1, ZOU Guoping1
(1. College of Information Engineering, China Jiliang University, Hangzhou 310018, China; 2. Zhejiang Gaoxin Technology Co., Ltd., Hangzhou 311200, China)
Abstract: In allusion to the islanding effect of grid connected inverters, a method of hybrid islanding detection with adaptive grid impedance is proposed. A hybrid islanding detection method combining passive and active methods is used for the analysis based on distributed generation systems. The voltage imbalance method is used in the passive method, while the zero sequence voltage positive feedback method is used in the active method. The active method only can be started when the passive method suspects islanding to avoid the power quality degradation caused by the active method. The voltage unbalance method is used to obtain the correlation formula between the threshold set by the passive method and the grid impedance by means of theoretical derivation, and the grid impedance is detected by means of the harmonic injection method, effectively solving the problem of difficulty in setting the threshold by means of the passive method. The effectiveness and anti?interference of the proposed method are verified by experiments. The experimental results show that the proposed method can effectively detect different network conditions and different local loads, and also has strong anti?interference ability to the voltage fluctuation of the network.
Keywords: grid?connected inverter; grid impedance; hybrid island detection method; harmonic injection method; threshold setting; passive method; active method
0" 引" 言
分布式發電系統是實現可再生能源有效利用的途徑之一。然而,各種并網逆變器和本地負載的接入導致電網電壓和電流具有復雜和不確定性,孤島效應便是穩定問題的其中之一[1?2]。
此外,為解決并網逆變器對并網點電網阻抗的不確定性以及常見被動式孤島檢測方法閾值難以設定的問題[3?5],需要尋找能夠準確設定被動法閾值,并快速檢測出孤島及時斷開分布式發電系統的方法。
目前常見逆變器端的本地孤島檢測方法可以分為兩類:被動法[6?8]、主動法[9?11]。……