The reverse power relay prevents damage of the prime mover, turbine or motor, upon a reverse power condition. If the driving torque becomes less than the total losses in the generator and the prime mover, the generator starts to work as a synchronous compensator, taking necessary active power from the network. In case of steam turbines, a reduction of the steam flow reduces the cooling effect of the turbines blades and overheating may occur. Hydro turbines of the Kaplan type and bulb type may also be damaged due to the fact that the turbine blade surf on the water and set up an axial pressure on the bearing. Diesel engines may be damaged due to insufficiently lubrication.
The reverse power relay protection assemblies with RXPPK 2H can be delivered with different output circuits.
RXPPK 2H is a micro processor based relay with one measuring stage and two different definite time delay stages. The relay has two input transformers for current and voltages, filter circuits, HMI, LEDs for start, trip indications and three output units which provide separate change-over contacts for start and trip functions. The relay has also two binary inputs, one for reset of LEDs and the other to block or enable the trip function.