Longitudinal Protection Scheme of Doubly-fed Wind Farm Transmission Lines Based on Frequency Domain Model Matching
Aiming at the problem of wind farm transmission line protection adaptability caused by the difficulty of accurate analysis of the multi-machine grid-connected transient model of wind farms,this paper establishes a frequency-domain equivalence model for multi-machine grid-connected doubly-fed wind farms,and proposes a longitudinal protection scheme for doubly-fed wind farms based on the matching values of the frequency domain model.First,according to the low-voltage ride-through control mode under the fault of the doubly-fed fan,the current response model of the doubly-fed unit is derived.On this basis,considering the coupling relationship between different feeder resistance inductances and the influence of phase-locked loop phase angle offset,a multi-machine grid-connected frequency-domain equivalence model of doubly-fed wind farm is established.Then,according to the fault network analysis of the outgoing line fault model,the matching value of the frequency domain model is defined,and the protection criterion for identifying the fault inside and outside the transmission line is constructed.Finally,a simulation model is built on the RT-LAB platform to conduct verification tests,and the protection scheme can quickly and accurately cut off the fault in the area by passing through different transition resistance ground faults at different positions of the transmission line.
doubly-fed wind farmsshort-circuit currentslow-voltage ride-through controllongitudinal protectionfrequency domain model
万方数据
维普
