风电场在公共连接点的闪变

依据并网风电机组电能质量的国际电工标准IEC61400-21规定,基于单台风力发电机组连续运行和切换运行的闪变计算,分析了风电场在公共连接点处的闪变值计算方法,推导出同种机型组成的风电场容量的计算方法。以1.5 MW双馈机组为示例风机组成风电场,取3台机组的实测闪变系数平均值为正常范围的计算依据,计算了不同系统短路容量下风电场允许安装的风机台数。以国家标准GB12326-2000对电压波动和闪变的规定为参考限值,对闪变超标的单台机组,以及闪变值符合电能要求的单台机组进行了对比分析,绘出系统短路容量、闪变系数及风电场容量的关系曲线。结果表明风电场内的单台机组闪变系数在正常范围内,即使公共连接点处的短路容量较小,闪变也不会成为风电场容量的限制因素。单台机组的闪变系数接近限定值,机组的闪变值及系统短路容量的大小都是限制风电场容量的主要因素。

Flicker at common coupling point of wind farm

The method of flicker computation at the common coupling point of wind farm is analyzed based on the flicker computation of single wind turbine for continuous or switching operation according to IEC61400-21,and that of capacity computation of wind farm with multiple wind turbines of same type is deduced.With 1.5 MW doubly-fed wind turbine as example and the average of measured flicker coefficients of three wind turbines as its flicker coefficient,the number of possibly installed wind turbines is calculated for different short-circuit capacities of wind farm. Based on GB12326-2000 concerning voltage fluctuation and flicker,the comparison between single wind turbine with normal flicker and that with violation is carried out,and the relation curves among system short-circuit capacity,flicker coefficient and wind farm capacity are given.The result indicates that,the flicker will not become the main limitation factor of wind farm capacity if the flicker coefficient of single wind turbine is regulated in normal range though the short-circuit capacity is smaller;if the flicker coefficient of single wind turbine is close to its limit,both the flicker and the system short-circuit capacity will become the main limitation of wind farm capacity.