Finely adjustable diode rectification type DC ice melting device and method

Abstract

The invention relates to the technical field of ice melting for power grids, and discloses a diode rectifier type direct current ice melting device and method with finely adjustable output voltage. Fine adjustment of direct current output voltage and current of the diode rectifier type direct current ice melting device within a relatively large range is realized by using a few of transformer gearpositions. The device comprises a coarse gear position adjustment transformer, a high-capacity rectifier, a fine gear position adjustment transformer and a low-capacity rectifier. The primary side ofthe coarse gear position adjustment transformer is connected with the power grid, and the secondary side of the coarse gear position adjustment transformer is provided with at least two gear positionswith relatively large span lengths; an output port is connected with the high-capacity rectifier; the primary side of the fine gear position adjustment transformer is connected with the power grid, and the secondary side of the fine gear position adjustment transformer is provided with at least two adjustable gear positions with relatively narrow span lengths; an output port of the fine gear position adjustment transformer is connected with the low-capacity rectifier; after the direct-current output sides of the high-capacity rectifier and the low-capacity rectifier are connected in series, atotal ice melting voltage is output. The diode rectifier type direct current ice melting device realizes fine adjustment of the ice melting output voltage of the diode rectifier type direct current ice melting device within a relatively large range only by using a few of transformer gear positions, and is relatively low in cost and high in ice melting performance.

Description

technical field [0001] The invention relates to the technical field of grid ice melting, in particular to a finely adjustable diode rectification type DC ice melting device and method. Background technique [0002] Ice and snow disasters occur frequently in southern China. Ice-covered power transmission lines are likely to cause disconnection and downturning, which seriously threatens the safe and stable operation of the power grid and the reliability of power supply. [0003] For this reason, various types of DC ice-melting devices have been developed in China. These devices can be divided into three types: uncontrolled rectification based on diodes, phase-controlled rectification based on thyristors, and fully-controlled rectification based on switching devices such as IGBTs. Among them, the harmonics on the grid-connected side of the fully-controlled rectifier-type ice-melting device are controllable and the DC voltage on the output side is continuously adjustable, and th...

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Problems solved by technology

In order to meet the above-mentioned voltage output requirements, the existing diode rectification ice-melting device is generally realized by configuring more transformer gears (including configuring multiple transformers, and each transformer corresponds to several output voltage gears). The number of gears or even transformers is large and the cost is high; or only a few voltage gears are configured loosely. At this time, there are few operating points of the ice-melting output voltage for selection, and the actual ice-melting voltage and current often deviate from the optimal operating point, resulting in The ice-melting current is small and the ice-melting process is long. According to calculations, when the actual ice-melting current is 10% smaller than the suitable working point, the ice-melting time will increase by 40-50%. Features are not ideal

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