Single-pole grounding protection method for multi-terminal flexible DC transmission line based on zero-mode increment
The fault of the flexible DC system is usually a single-pole grounding fault.After the fault occurs,the protection should isolate the fault line within a few milliseconds to avoid adversely affecting the entire system.How to realize fast and reliable identification of the fault line is an important problem to be solved in MTDC DC line protection.Firstly,the fault characteristics of the line after modulus decomposition are analyzed.Secondly,the correlation of the zero-mode current increment at the protection installation at both ends of the line and the direction of the zero-mode voltage increment are used to construct the integrated protection criterion,and a single-pole grounding fault protection scheme based on zero-mode increment is proposed.This method can complete fault identification within 1 ms after the fault occurs,and can accurately perform identification under the 500 Ω transition resistance,taking into account both speed and reliability.Finally,the feasibility and superiority of the protection scheme are verified by simulation.
flexible DC transmissionsingle-pole grounding faultline protectionmodulus decompositioncorrelationintegrated criterion
NETL
NSTL
万方数据
