新型整流桥串并联切换直流融冰装置

我国南方地区冬季气温低湿度高，在远距离传输的高压输电线路上经常出现区域覆冰问题，覆冰严重时会造成杆塔倒塌等电力事故，本文研究的新型整流桥串并联切换直流融冰装置即用于解决输电线路覆冰问题，避免造成大面积供电中断。本文基于常规十二脉动直流融冰装置，通过原理分析、参数设计和仿真验证提出一种新型直流融冰拓扑，可以同时满足导线融冰的大电流和地线融冰的高电压需求。相比于常规十二脉动直流融冰装置，采用新型直流融冰拓扑可以选用一半容量的换流变压器和一半电流定额的晶闸管，显著降低设备成本；在大电流输出模式下可以有效减小注入系统的谐波电流，从而减小接入点的系统电压畸变。本文研究的新型整流桥串并联切换直流融冰装置有利于降低直流融冰装置的设备投资成本，同时改善直流融冰装置投入运行时的系统电压质量。关键词：线路覆冰；直流融冰装置；串并联切换；切换刀闸；平衡电抗器；成本优势中图分类号：TM755

New DC ice-melting device with the function of series-parallel switching of rectifier bridge

The winter in southern China is very cold, along with high humidity. Regional ice coating problem often appears in the long distance HV transmission lines, which may lead to serious power accident such as tower collapse. A new dc ice-melting device with the function of series-parallel switching of rectifier bridge is studied in the paper to solve the problem to avoid wide-spread power outages. Based on the conventional 12-pulse dc ice-melting device, a new dc ice-melting topology is proposed through principle analysis, parameter design and simulation verification, which can simultaneously meet the high current de-mand of wire melting and the high voltage demand of ground wire melting. Compared with the conventional 12-pulse dc ice-melting device, the new dc ice-melting topology is able to select half-capacity transformer and half-current thyristor, which can significantly reduce the equipment cost. Meanwhile, the harmonic current injected into the system can be effec-tively reduced when operating in high current output mode, so as to reduce the voltage distortion of the connected system. The new dc ice-melting device with the function of series-parallel switching of rectifier bridge is able to reduce the equipment in-vestment and improve the system voltage quality when the dc ice-melting device is put into operation. Keywords: ice coating of transmission line; dc ice-melting device; series-parallel switching; mode switching disconnector; balanced reactor; cost advantage