Voltage and Power Regulation of an Induction Generator-Based Hydroelectric Power Plant

The paper considers an induction generator-based hydro power generation system (HPGS) with a regulated hydro turbine (HT). The HPGS can operate as a grid connected system and as an emergency generator when power grid fails. The system consists of a HT, an induction generator (IG), no load capacitors (NLC), contactor-switched capacitors (CSC), a dump load (DL), a step up power transformer and a distribution transformer connected to a transfer switch (TS). A procedure for synchronization the IG with the grid is proposed and block diagram of a synchronization controller (SC) is developed. The SC control strategy is based on the edge detection method. NLC and CSC power ratings are determined using performance characteristics of the IG and the IG voltage reference limits in standalone mode (SM) of the system. The proposed control algorithm for hysteresis controllers (HYC) provides dead band reactive power (RP) regulation of the HPGS at the point of common coupling (PCC) in grid-connected mode (GM) and hysteresis voltage control in SM. Electric frequency control of the HPGS during the IG synchronization with the grid is carried out using a regulated DL. The HT wicket gate (WG) angle reference in SM of the HPGS was proportionally adjusted to local load demand. Simulation of the HPGS during its synchronization with the grid and in SM has been performed and discussed.