電網阻抗自適應的混合式孤島檢測方法

摘" 要： 針對并網逆變器存在的孤島效應，提出一種電網阻抗自適應的混合式孤島檢測方法。首先，采用被動法與主動法結合的混合式孤島檢測方法，基于分布式發電系統進行分析。其中被動法采用電壓不平衡法，主動法采用零序電壓正反饋法，主動法僅在被動法懷疑發生孤島時啟動，以避免因主動法導致的電能質量下降。其次，采用電壓不平衡法，通過理論推導獲得被動法設定閾值與電網阻抗的關聯式，通過諧波注入法檢測電網阻抗，從而有效解決被動法閾值設定困難的問題。最后通過實驗驗證所提方法的有效性和抗干擾性。實驗結果表明，該方法對于不同電網情況以及不同本地負載均能有效檢測，對于電網電壓波動的情況也具有較強的抗干擾能力。

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]。……