摘要
针对输电线路覆冰严重影响特高压直流输电可靠性的问题,研究了特高压直流输电线路融冰的2种方案:预防性融冰方案和紧急融冰方案。预防性融冰方案是使特高压直流工程的2个极功率方向相反,可以在直流双极总功率很小的情况下实现较大的线路电流,防止线路覆冰形成;紧急融冰方案是将特高压直流换流器从串联接线方式转换为每站2个换流器并联运行,产生很大的融冰电流,可迅速融化已经形成的覆冰。文中提出了特高压直流工程紧急融冰方案的控制策略,即整流侧并联的2个换流器均处于定电流控制,逆变侧并联的2个换流器一个为定电流控制、另一个为定电压控制,逆变侧定电流换流器的电流参考值为线路电流测量值的一半,达到平均分配电流的目的,定电压状态的换流器控制整个极的直流电压。上述融冰方案的实施将大大降低覆冰对特高压直流输电系统可靠性的影响。
Ice-coating of overhead transmission lines is harmful to the reliability of ultra high voltage direct current （UHVDC）. This paper discusses two kinds of de-icing schemes for UHVDC. One is preventive and the other is of emergency. In the preventive scheme, the power flows in opposite directions in the two poles, which forms high current and low net power to prevent the formation of ice. In the emergency scheme, dual converters are connected in parallel instead of series-connection mode at each station; high direct currents are formed to melt the ice quickly. The control strategy of emergency de-icing scheme for UHVDC system is presented, the parallel converters at the rectifier side are both in current control, and at the inverter side, one is in current control and the other is in voltage control. The reference value for the current controlled inverter is half of the measured DC line current to balance the paralleled converters, the voltage controlled inverter controls the voltage of whole pole. The proposed de-icing scheme can greatly improve the reliability of UHVDC by mitigating the influence of icecoating.
出处
《电力系统自动化》
EI
CSCD
北大核心
2009年第7期38-42,共5页
Automation of Electric Power Systems
基金
国家电网公司科技项目(SGKJ[2007]87)~~
关键词
融冰
特高压直流输电
控制策略
控制保护系统
换流器
de-icing
ultra high voltage direct current （UHVDC）
control strategy
control and protection system
converter
