Abstract
Several causes may affect a Mini-Hydro generator to shut down whilst in operation. They can be the earth faults in the electricity lines (mainly way tree leaves touching the transmission lines), lightning, planned and unplanned interruptions in that particular area connecting to the load bus of the distribution network and for maintenance of the plant itself. To resume power export to the grid after each shutdown will require generator to synchronize with the grid supply. Since the generator Rotor-Turbine assembly is a heavy massed system and t he viscous damping is very low, stabilizing of rotor speed at the reference set point is a time taking exercise. The time taken for synchronization will typically be in the range of 2-10 minutes depending on the plant design. This paper describes the work of authors on the development of a speed stabilizer to minimize synchronization time of a chosen Mini-Hydro generator plant. This involves the modeling of the entire plant, identifying of damping strategies, designing of power electronic switching circuit and associated closed loop control, MATLAB simulation for parameter fine-tuning and final site testing. The designed system introduces a controlled resistive load on die generator during the synchronization transient to expedite settling. Test results confirmed the reduction of synchronization time as expected.