IV. SIMULATION STRUCTURE AND RESULTS
A test system is built with real data from a WF in Hebei Province, and a simulation module is constructed to simulate closed loop control process as shown in Fig. 4: AVC module obtains PF solution from simulation module, and then sends the calculated commands back in every five seconds. While in the simulation module, recursive PF calculation is applied to simulate the execution process of different reactive power devices with different time constant. Each PF calculation costs less than fifty milliseconds.