电力系统保护与控制2025，Vol.53Issue(5)：35-46,12.DOI:10.19783/j.cnki.pspc.240671
基于固有频率的海上风电接入柔直系统的交流送出线路纵联保护原理
A novel pilot protection for AC transmission lines of VSC-HVDC connected offshore wind farms based on natural frequency
摘要
Abstract
When asymmetric faults occur in the AC transmission lines of offshore wind networks,the reliability of traditional differential protection is reduced because of the effect of capacitive current in the negative sequence network,as the converters on both sides of the line adopt negative sequence suppression control strategies.To address this issue,this paper first outlines the structure of the offshore wind power transmission system and analyzes the fault characteristics through the control strategies of power electronic equipment on both sides of the transmission line.Considering capacitive current,the adaptability of longitudinal differential protection and the blind area of natural frequency differential protection are then evaluated.On this basis,using the negative sequence voltage of the offshore MMC busbar and the sum of the positive sequence currents on both sides of the line,a location-indicating variable λ is constructed and is further used to construct an auxiliary protection criterion.Finally,an offshore wind power system model is built in PSCAD/EMTDC to analyze and verify the effectiveness of the proposed protection scheme.The results show that the proposed method exhibits high reliability,fast response,and can tolerate 20 dB noise and 100 Ω fault resistance.关键词
海上风电/交流送出线路/纵联保护/固有频率/负序电压Key words
offshore wind power/AC transmission line/pilot protection/natural frequency/negative sequence voltage引用本文复制引用
戴志辉,韩哲宇,李杭泽..基于固有频率的海上风电接入柔直系统的交流送出线路纵联保护原理[J].电力系统保护与控制,2025,53(5):35-46,12.基金项目
This work is supported by the Natural Science Foundation of Hebei Province(No.E2024502043). 河北省自然科学基金项目资助(E2024502043) （No.E2024502043）
