This rig allows for understanding of synchronous power generation and the effects connecting to the Grid (Infinite Bus) as well as for the studying of the effects of varying prime mover power and field current on the generated power, voltage and current.
In order to study the behaviour of a synchronous generator connected on to a large system, a 415 V, 15 kVA, 4-pole,50 Hz, star-connected synchronous generator is synchronised to the 415 V, 50 Hz mains power supply. The mains power supply is so strong that the 15 kVA generator behaves like a small generator connected to a large system, thus the small generator cannot change the supply (mains) frequency or voltage. In the experiment, the turbine is simulated by an inverter-fed induction motor. The power to the shaft is increased by increasing the frequency of the inverter. That is, the generator shaft power is controlled by changing the firing frequency of the inverter. The firing frequency is controlled by a 0-10 V analogue dc signal input to the inverter controller. The field winding is supplied by a DC supply of rating 0 ~ 60 V, 0 ~ 10 A. The DC supply output can be controlled remotely by applying a 0-10 V signal to the controller. In the laboratory set-up, these two controls are done by the analogue outputs from a data acquisition (DAQ) board installed on a PC. The DAQ board is controlled by the LabView software.