Small-Hydro Battery Energy Storage System With Mode Transfer Capabilities

This work presents the synchronization of the small hydro system with the utility grid based on a re-weighted zero attracting logarithmic hyperbolic cosine based adaptive algorithm (RZA-LHCAF). The system consists of a battery connected at DC link with a buck-boost converter to maintain the power balance, voltage source converter that maintains the terminal voltage and frequency of the system in the standalone mode. Moreover, in the grid connected mode it is maintained by the utility grid. Apart from maintaining the voltage and frequency of the system, the voltage source converter also helps in mitigating harmonics produced due to nonlinear loads and compensates for the reactive power requirement of the load thus need not require any additional compensating device. The small hydro system incorporates a synchronization control algorithm that synchronizes the system to the utility grid. The utility grid operates at unity power factor. The system is simulated and results are presented in the grid connected mode, islanded mode as well as in the transition mode. The control algorithm implemented depicts improved power quality results. The THDs of the grid currents and machine currents as well as voltages adheres to the IEEE 519–1547 standard.