一种适用于不对称故障下永磁直驱风电机组的动态等效方法

In this paper,a dynamic equivalent method applica-ble to the direct-drive permanent magnet synchronous genera-tor(PMSG)based wind farms under asymmetrical faults is pro-posed.Firstly,PMSGs are clustered based on their different ac-tive power characteristics under asymmetrical faults.Further,single-machine equivalent models(SMEMs)are constructed for different clusters of PMSGs.In particular,an SMEM with multi-segmented slope recovery is introduced for PMSGs with ramp recovery characteristics.Further,a collector network equivalent method for wind farms applicable to both symmetri-cal and asymmetrical faults is presented.Moreover,an iterative simulation method is used to gain the required clustering indica-tors before the fault actually occurs.Eventually,the effective-ness of the proposed dynamic equivalent method is verified on a modified IEEE 39-bus system.