Performance test of axial turbine-generator magnet permanent on-grid system prototype for very low head application

Abstract

In order to promote and develop the New and Renewable Energy (NRE) utilization, the Indonesian government had issued a policy that allows the connection of NRE power plant to the grid. One of the NRE potential in the country is the hydro power. In Indonesia, there are abundant number of rivers with characteristics of large flowrate and low head, that are considered as one of the potential for New and Renewable Energy (NRE). This study was aimed to investigate the performance of on-grid hydro power plant system prototype utilizing very low head potential (<1m) river. The prototype system consisted of an Axial Turbine Permanent Magnet Generator (ATPMG) which had been designed to operate at speed of 90 rpm, flow rate of 128 liter/second and head of 30 cm. It was capable to generate AC power 300 W at 220V 50Hz, while it was connected to automatic voltage stabilizer to maintain the voltage at 220V. The AC to DC power was converted by diode rectifier with π filter to minimize DC voltage ripple, next connected to Grid Tie Inverter (GTI) which has MPPT to inject maximum AC power to the grid. The ATPMG was placed on an open water canal with cross section dimension 84x115 cm. The characteristic of ATPMG AC power, DC power before connected to GTI and on-grid operation on variation of flow rate range 0.199 m3/s to 0.326 m3/s was discussed in this paper. The highest on-grid system efficiency was 4.71% with maximum injected power to the grid of 37.37 W, and was achieved at the flow rate of 0.270 m3/s and the head of 30 cm. The small efficiency and power of the system was caused by decreasing PMG performance in ATPMG.