Method for automatically switching between DC ice melting three-phase AC line

Abstract

The invention relates to a method for automatically switching a DC ice-melting three-phase AC circuit. A DC ice-melting main loop comprises a rectifier, a control protection device, and DC side switches. A three-phase AC power supply is connected to a three-phase input of a valve group of the rectifier, namely a current converter. An anode output and a cathode output of the rectifier are connected to the three-phase AC circuit needing the ice-melting respectively through two groups of DC side isolation switches in a DC ice-melting mode to form the DC ice-melting main loop, and DC ice-melting is carried out on the three-phase AC circuit. The DC side isolation switches are controlled to automatically switch a three-phase conducting wire to connect the rectifier for the ice-melting by operating the control and the DC side isolation switches according to the operation state of ice-melting equipment. The operation of the rectifier and the DC side switches is controlled by an automatic sequence in the switching process. The method makes the three-phase conducting wire evenly heated, reduces the switch transferring operation of switching on or switching off the switches and the wire connecting work in ice-melting sites at the same time, and greatly improves the safety and reliability of systems.

Description

technical field [0001] The invention relates to a method for automatic switching of a DC deicing three-phase AC line and a device applying the method. Background technique [0002] Icing of transmission lines in winter seriously threatens the safe operation of the power system. Due to the increased ice load on the conductors, it will cause certain mechanical damage to the conductors, iron towers and fittings. When the ice is severe, the wires will be broken and the towers will fall, resulting in large-scale power outages and great losses to the national economy. [0003] Several ideas for research on ice melting at home and abroad are as follows: convert electrical energy into heat energy to melt ice; deicing. After the ice disaster in the United States and Canada in 1998, the international community attached great importance to the research on anti-icing, anti-icing and ice-melting technologies, but none of them entered the practical stage. [0004] Since the 1970s, my c...

AI Technical Summary

Problems solved by technology

But so far, the device has not completed field commissioning

In references [1] and [2], AREVA’s ice-melting schemes only give the wiring diagram of the main circuit, and do not give the automatic switching method of the three-phase AC line using DC ice-melting.

In addition, reference [3] discloses two methods of DC ice melting for balanced ice melting, but does not disclose the specific operation steps and switching conditions when the automatic control device realizes automatic switching

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