Static synchronous compensator-variable frequency drive for voltage and frequency control of small-hydro driven self-excited induction generators system

In this study, a static synchronous compensator (STATCOM) along with a variable frequency drive (VFD), is proposed for voltage and frequency control of a small-hydro turbine driven self-excited induction generator (SEIG) system. STATCOM is used to control SEIG terminal voltage through variable reactive power injection. A control algorithm based on adaptive noise cancellation filter is proposed for STATCOM control. A field oriented controlled VFD feeding an induction motor is used to control system frequency. The VFD consumes active power in excess of consumer loads and thereby it regulates the system frequency. The excess power consumed by the VFD is utilised for pumping water to either an overhead storage tank or irrigation purposes. Besides the voltage control as primary objective, the STATCOM also provides harmonic currents compensation and load balancing under unbalanced non-linear loads. The proposed method of voltage and frequency control using STATCOM-VFD combination is implemented on a 3.7 kW SEIG and the test results are presented to demonstrate its performance.