This paper focuses on addressing the network fault handling problem in all-DC offshore wind farms.Firstly,fault control strategies for DC wind turbine units are investigated to enhance the safety of the units using the machine-side converter and unloading chopper circuits.Secondly,an improved topology of the grid-side DC/DC converter for DC wind turbines is proposed,which utilizes pulsed discharge of the grid-side capacitor in the DC/DC converter to perform traveling wave-based fault location.Finally,a fault control and restoration scheme based on DC circuit breakers is presented for the DC collection network.An all-DC wind farm model is built in PSCAD/EMTDC,and the effectiveness of the proposed fault control and restoration strategies is verified through simulations in various fault scenarios.
维普
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