风电场无功分层配置的思考与例证

Analysis and Site Trial on Hierarchical Control of Reactive Power in Wind Farms

目前并网的风机几乎都长期运行在功率因数为1的方式下,由升压站的无功补偿设备对风机箱变、集电线路、升压变及并网线路的无功损耗进行补偿。这种运行方式不仅与无功分层平衡就地补偿的原则不符,也对风机机端电压的调整不利,在故障情况下还会扩大风机脱网的规模。本文从现场调试的试验结果出发,根据实例提出了风电场的无功补偿主要来自风机发出无功功率的补偿方式,符合无功分层平衡就地补偿的原则,而且有利于风机机端电压的调整,在故障情况下还能避免无功潮流对电网的冲击,减小风机脱网的规模。

Most grid-connected wind turbines nowadays are operating in a unity power factor mode. Reactive power loss of box transformer substations and feeders are compensated in step-up substation to meet the requirement of reac- tive power balance in wind farm transmission line. This operation mode doesn＇t comply with the principle that reactive power should balance in local. And it is not conductive to voltage adjustment of wind turbine. In some serious condi- tion,this would lead to more wind turbines disconnection from grid. This paper analyzed some site trials of wind tur- bines and drew a conclusion that wind turbines should generate reactive power as well as active power, compensating reactive power loss of box transformer substations and feeders instead of compensators in step-up substation. This op- eration mode is conductive to local reactive power balance principle and helpful to voltage control of wind turbines. Moreover, in serious fault condition, it would help line voltage to keep steady and avoid wind turbines from drop-off.