The whole process of putting the generators into parallel operation is called parallel operation. One generator set is run first, and the voltage is sent to the busbar, while the other generator set starts and is parallel with the previous generator set. It should be switched on at the moment of closing. There is no harmful inrush current in the generator set, and the special axis is not subject to sudden impact. After closing, the rotor should be pulled into synchronization very quickly. (that is, the rotor speed is equal to the rated speed) Therefore, the generator sets must meet the following conditions:
1. The effective value and waveform of the generator set voltage must be the same
2. The voltage phases of multiple generators are the same
3. The frequency of multiple generator sets is the same
4. The phase sequence of multiple generator sets is consistent.