Abstract: This article analyzed the characteristics of DC ice-melting device with full bridge MMC topology, and pointed out that DC ice-melting device with full bridge MMC can also operate in SVG mode without de icing. Reactive power compensation equipment in the station was replaced, equipment utilization was improved and investment and land occupation of reactive power compensation equipment was reduced. The advantages and disadvantages of direct and step-down full bridge MMC de icing devices in engineering applications were studied for conventional 500 kV substations, and engineering application scope was proposed.