Direct current de-icing device based on full-bridge modular multilevel converter

Abstract

The invention discloses a direct current de-icing device based on a full-bridge modular multilevel converter. The full-bridge modular multilevel converter has a three-phase bridge structure, each phase of the converter comprises an upper bridge arm and a lower bridge arm, the upper and lower bridge arms which are respectively formed by serially connecting N full-bridge power modules end to end, and the full-bridge power modules form a chain type multilevel structure, the front ends of the first power modules of the upper bridge arms of all phases are connected to form the positive pole of a public direct current bus; the tail ends of the Nth power modules of all lower bridge arms of all phases are connected to form the negative pole of the public direct current bus; the tail ends of the Nth power modules of all upper bridge arms are connected with the front ends of the first power modules of the respective lower bridge arms of the phases by smoothing reactors; and the center of the electric reactor serves as the alternating current bus of the phase. The device has high high-voltage direct current output capacity and the direct current voltage of the device can be regulated continuously from zero; on the other hand, the fully compatible chain type scalable vector graphics (SVG) topology can realize quick dynamic reactive regulation; and the device has the combined functions of direct current de-icing and alternating current dynamic reactive compensation.

Description

technical field [0001] The invention belongs to the technical field of power electronic converters, and in particular relates to a DC ice-melting device for a power grid. Background technique [0002] In recent years, extreme rainy and snowy weather frequently occurs in southern China in winter, and DC ice-melting devices have been widely used in power systems. The traditional DC ice-melting device adopts thyristor rectification technology, which converts AC power into amplitude-adjustable DC power through phase-controlled rectification for deicing transmission lines. Since the ice melting device is only used under extreme weather conditions in winter, the equipment utilization rate of the device is low, which brings additional burden to the power transmission and distribution enterprises. [0003] In order to improve the equipment utilization rate of the ice melting device, the combination with the static var compensator (SVC) has become the mainstream technology of the DC...

AI Technical Summary

Problems solved by technology

However, using HVDC Light technology to melt ice also has some limitations, the most prominent of which is that the adjustable range of the HBMMC output DC voltage is small, and it must be adjusted above the DC voltage that meets the controllable rectification conditions, which cannot effectively adapt to different lengths of power transmission. line, so the availability of the device will be greatly reduced

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