Calculation Method for Fault Response Characteristics of Renewable Energy Sending-end Flexible DC Grid-forming Transmission System
Fault equivalent modeling is the basis of system-level response characteristic calculation.However,there are few studies on fault equivalent modeling of grid-forming converters.The traditional short-circuit current calculation method for grid-following power electronic devices connected to AC network is prone to the problem of instability divergence in the flexible DC grid-forming system.Therefore,considering the voltage-frequency grid-forming control strategy and the active voltage reduction strategy of grid-forming flexible DC converters and the low voltage ride-through control strategy of grid-following renewable energy,this paper establishes the fault equivalence model of different types of power electronic devices.On this basis,considering the frequent switching of equivalent models of voltage source and current source for different power electronic devices,a network-wide chain iterative calculation method for fault response characteristics of renewable energy sending-end flexible DC grid-forming transmission system is proposed to realize the fast and reliable convergence of short-circuit current calculation.Based on the PSCAD/EMTDC simulation platform,a simulation model of the renewable energy sending-end flexible DC grid-forming transmission system is built to carry out a large number of simulation tests of various fault types and influencing factors,which fully verify the feasibility,accuracy and superiority of the proposed calculation method.
flexible DC convertergrid-forming controlfault equivalent modelfault response characteristicchain iteration
万方数据
维普
