Research on MMC de-icing system capable of power grid interconnection

Voltage sourced converter (VSC) de-icing device has been gradually applied because of its advantages, such as no requirements on by-pass transformer, no harmonic output on AC side, and small floor area. However, the DC de-icing device will only operate in winter, resulting in low utilization rate. In order to improve the utilization rate of equipment and the power supply reliability of the distribution network, this paper analyzes the current situation of DC de-icing technology and proposes a VSC-HVDC de-icing system composed of two sets of voltage-source DC de-icing devices, which can improve the de-icing efficiency in parallel; Some strategies are proposed, such as AC power balance control of sectionalized busbar under VSC interconnection of de-icing devices as well as emergency power transfer for AC single-end power loss. The paper also builds an EMTDC simulation model of the VSC DC de-icing system and carries out a simulation test, which verifies the functions of the VSC-HVDC de-icing system, such as ice-melting, VAR compensation, AC power balance, and emergency power transfer for AC single-end power loss, etc. The related functions are also verified in the engineering site, which shows that the VSC-HVDC de-icing system proposed in this paper can improve the power supply reliability of distribution substations.