一种新型柔性直流电网金属回线不停电融冰方案  

A New Melting Scheme for Metallic Return of Flexible DC Grid Without Power Cuts

作　　者：夏嘉航 赵成勇[1] XIA Jiahang;ZHAO Chengyong(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University,Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学)

出　　处：《南方电网技术》2019年第12期9-16,共8页Southern Power System Technology

摘　　要：冰雪灾害引起的输电线路覆冰对直流电网危害极大,因此融冰技术研究与应用对于直流电网抗击冰灾具有重大的意义。正常情况下,金属回线电流为零,不具有防冰效果,因此对其进行融冰尤为重要。采用电流的热效应对金属回线进行融冰,首先计算了四端柔直电网中金属回线的临界融冰电流和不同融冰电流对应的融冰时间,并建立了含金属回线的直流电网潮流计算模型。采用双极换流站功率异向的方式对金属回线进行融冰,选取了不同的融冰工况对四端电网进行融冰分析,得到最为适用的融冰工况,并对融冰控制过程进行仿真分析。最终得出结论,双极功率异向方式较适用于金属回线融冰,可实现不停电融冰,且对换流站功率要求较小。Ice coating caused by ice and snowdisasters is extremely harmful to DC power grids. Therefore,the research and application of ice melting technology are of great significance for DC grids to combat with ice disasters. In normal operation,the current of metal return is zero and does not have an anti-icing effect,so it is especially important to discuss it. The paper uses the thermal effect of current to melt the metallic return. Firstly,the critical ice-melting current of the metal return in the four-terminal flexible DC grid and the ice-melting time corresponding to different melting currents are calculated,and the power flowcalculation model of DC grid with metallic return is established. The paper innovatively uses the bipolar converter station power reversed method to melt the metallic return,selects different ice-melting conditions,and analyzes the ice-melting of the four-terminal power grid to obtain the most suitable ice-melting conditions. The simulation analysis of the ice-melting control process is carried out. Finally,it is concluded that the bipolar reversed power mode is more suitable for melting the metallic return,which can realize ice-melting without power failure and has less power requirement for the converter station.

关 键 词：柔性直流电网 直流线路融冰 融冰计算 金属回线 双极功率异向 

分 类 号：TM721[电气工程—电力系统及自动化]