Improved power conditioning system of micro-hydro power plant for distributed generation applications

Abstract

A small-scale hydropower station is usually a run-of-river plant that uses a fixed speed drive with mechanical regulation of the turbine water flow rate for controlling the active power generation. This design enables to reach high efficiency over a wide range of water flows but using a complex operating mechanism, which is in consequence expensive and tend to be more affordable for large systems. This paper proposes an advanced structure of a micro-hydro power plant (MHPP) based on a smaller, lighter, more robust and more efficient higher-speed turbine. The suggested design is much simpler and eliminates all mechanical adjustments through a novel efficient electronic power conditioning system (PCS) for connection to the electric grid. In this way, it allows obtaining higher reliability and lower cost of the power plant. Moreover, a full detailed model of the MHPP is derived and a three-level control scheme is designed, comprising a full decoupled current control strategy in the synchronous-rotating d-q reference frame. The dynamic performance of the proposed systems is fully validated by digital simulation carried out by using SimPowerSystems of MATLAB/Simulink.