潮流计算中风电场的等值

Equivalence Method of Wind Farm in Steady-State Load Flow Calculation

潮流计算是风电场接入系统设计中的重要环节之一,为得到准确的潮流计算结果,以建立风电场稳态模型十分必要。以往风电场系统潮流计算都将风电场视为PQ节点,并认为风电场功率因数与单台机组功率因数相同。由于该方法未计入风电场内部集电系统的影响,当风电场规模较大时可能带来较大计算误差。作者通过实例将风电场集电系统分为使用架空线路和使用电缆两种情况,指出当风电场集电系统使用电缆时,风电场的等值功率因数与单台机组存在较大差别,潮流计算时应计及集电系统的作用。

Steady-state load flow calculation is an important constituent in conceptual planning of wind farm. To obtain accurate calculation results it is very necessary to build up a steady-state model that can accurately describe the characteristics of wind farm. Generally, in its load flow calculation the wind farm is regarded as PQ node and the power factor of a wind farm is considered as same as that of a single wind turbine. Because such a method does not take the collection system within the wind farm into account, it may cause larger calculation error when the scale of wind farm is biggish. Through case study the collection system of wind farm is illustrated by means of dividing it into two complexions, i.e., the collection system using overhead line and that using cable. It is pointed out that when cable is used as collection system, the equivalent power factor of a wind farm is evidently different from that of single wind turbine, thus in load flow calculation the action of collection system should be taken into account.