计及换流器矢量控制的海上风电柔性低频输电系统对称故障短路电流解析计算OA

The fault transient characteristics of offshore wind farms interconnected via flexible low-frequency transmission systems are greatly affected by the converter control links.Existing fault current calculation methods neglect the converter control-induced transient processes,leading to significant errors.This poses challenges for setting protection device parameters and designing fault ride-through strategies.To address these issues,this paper proposes an analytical fault current calculation method that accounts for the vector control characteristics of both the grid-side converter(GSC)of wind turbines and the modular multilevel matrix converter(M3C)station.Firstly,equivalent source models incorporating the post-fault active regulation effects of the converters are developed.Secondly,to resolve the coupling problem of fault currents from the two converter sides at the fault resistance,this paper implements an effective system decoupling strategy based on partitioned calculations.To address the coupling issue between the d-and q-axis components of the M3C low-frequency side fault current,this paper also proposes a novel method employing common-factor-based decoupling operations,which enables the analytical calculation of the M3C station dq-axis currents,accurately capturing the transient response of its dual-loop control systems.Finally,the model is built on both the PSCAD/EMTDC simulation platform and the RTDS experimental platform.The simulation and experimental results validate the accuracy of the proposed method.Furthermore,the comparison with existing fault analytical calculation methods demonstrates the superiority of the proposed approach.