Transient behaviour of an induction generation in small hydro plants

The transient behavior of an induction generator in a small hydro plant following disturbances in the utility's transmission and distribution system was studied, and some conclusions concerning the protection and control of small hydro plants with induction generators are drawn. Two perturbations were considered: a sudden loss of load situation and a three-phase short circuit in the feeder. In both cases it was assumed that reclosure of the utility's breaker would occur. From the studies performed it was concluded that the relays operated properly. In the situations considered both the over-frequency and the under-frequency relays were inhibited. It is stressed that the results are strongly dependent on the sizing of the shunt capacitor bank.<>