电力系统自动化2025，Vol.49Issue(9)：187-198,12.DOI:10.7500/AEPS20240610001
双极面对面模块化多电平换流器型直流变压器快速保护方案
Fast Protection Scheme for Bipolar Face-to-face Modular Multilevel Converter Based DC Transformer
摘要
Abstract
Isolated DC transformer(DCT)is the key equipment of multi-voltage-level DC system,which has multiple power conversion levels and multi-modular topology.However,when internal and external faults occur in DCT,the port fault characteristics are subject to the dual constraints of DCT nonlinear control and topology,and the traditional differential protection method is difficult to apply.In this paper,the bipolar face-to-face modular multilevel converter based DCT(FTF-MMC-DCT)is studied,and two bipolar FTF-MMC-DCT protection strategies based on port DC differential and leakage current are proposed.First,according to the current flow path under different fault types,combined with the MMC equivalent circuit,a fault analysis model of multi-level DC grid with DCT is established.On this basis,the differences in internal and external fault characteristics of DCT are summarized,and two typical fault characteristic quantities of DCT DC voltage and current differential and port leakage current are extracted.Then,two DCT protection schemes based on DC voltage and current differential and leakage current are designed,and the two methods are compared from the aspects of protection rapidity,sensitivity and reliability.Finally,a multi-level DC grid simulation model with bipolar FTF-MMC-DCT is built in PSCAD/EMTDC.The simulation results show that the designed protection scheme can quickly identify the fault within 2 ms,and has strong ability to withstand transition resistance.关键词
直流电网/直流变压器/模块化多电平换流器/快速保护/故障分析/漏电流Key words
DC grid/DC transformer/modular multilevel converter/fast protection/fault analysis/leakage current引用本文复制引用
廖建权,胡成彬,高仕林,谭子鹏,王渝红..双极面对面模块化多电平换流器型直流变压器快速保护方案[J].电力系统自动化,2025,49(9):187-198,12.基金项目
国家自然科学基金资助项目(52207126) （52207126）
四川省自然科学基金资助项目(2024NSFSC0869). This work is supported by National Natural Science Foundation of China(No.52207126)and Sichuan Provincial Natural Science Foundation of China(No.2024NSFSC0869). （2024NSFSC0869）
