Low-head Pico-hydro Plant using the Pump as Turbine (PaT) and Permanent Magnet Synchronous Generator (PMSG) for Isolated Loads: Experimental Studies

Abstract

Pico hydropower is a versatile power source providing electricity access for the world's poorest living in isolated locations. Though on a global scale, a significant market for such pico hydro systems exists in many countries, they are not widely used because they are not easily available, and the available head is low. One solution to address these issues comprehensively is using a pump as a turbine. However, in the case of a pump as turbine, studies on the performance of pico hydro systems are generally available only for heads above 10 m. To assess the technical feasibility of pico hydro plant at very low heads (less than 6 m), experimental studies were conducted using a pump as turbine (PaT) with a modified impeller vane coupled with a permanent magnet synchronous generator (PMSG). A power conditioner provided a stable output voltage of 220 V and a frequency of 50 Hz. The Pico hydro plant was evaluated with a test setup of a storage tank with a facility to have heads less than 6m and flow rates ranging from 6 to 9 liters per second. The results of the experiments at different heads – with and without power conditioner - are presented in tables and graphs, giving the output and efficiency of the different components of the system. Overall, it was demonstrated that this PaT could work at heads ranging from 2 to 4.5 m and at 4.5 m head with a flow rate of 7.5 l/s, the Pico hydro plant could generate a maximum power of 1.48 kW with an efficiency of 42%. The experimental setup was also used to power typical residential loads to demonstrate the effective applicability of this renewable energy resource. Overall, the results indicate the potential of Pico hydro systems that can help electrify communities to achieve SDG 7.1 using low-head hydropower resources.