PV Generator Performance Evaluation and Load Analysis of the PV Microgrid System in Thailand

Abstract

Normally, the main generators of microgrid system use controllable energy resources such as fossil fuel, biomass, biogas, hydro, etc for uncomplicated control. However, it is very challenging to control the microgrid system that uses uncontrollable energy resources such as solar and wind for main generators of microgrid system because they have many advantages. From this point, the PV microgrid system is constructed and operated at School of Renewable Energy Technology (SERT), Naresuan University for research and development of the microgrid system that is supplying 50% of total electricity demand by PV main generator. By measuring the important parameters such as solar irradiance, PV array voltage, PV array current, and AC electrical power, these data were collected for a year from November 2008 to October 2009 to use in evaluation processes. The PV generator evaluation result is revealed that the average reference yield (Yr), array yield (YA), and final yield (Yf) are 5.21, 4.32, and 3.84 kWh/kWp day respectively. The average total loss of the PV generator is 26.27% that comes from summing up the average capturelosses (LC) 17.21% and average system losses (LS) 9.06%. The average overall PV plant efficiency (ηtot) is 10.41%, and the average performance ratio (PR) is 73.45%. For load analysis of the microgrid, the total load is 231673 kWh/year or 635 kWh/day that the main loads of the microgrid are the real load and the battery storage loss. For the real load, it varies from 9803 to 22506 kWh/month and the average real load is 15434 kWh/month. However, the battery storage loss is really constant at 3888 kWh/month. When consider the load profile, it shows that the peak load period is 8 A.M. to 7 P.M. and the off peak load periods are 0 A.M. to 8 A.M. and 7 P.M. to 0 A.M. Moreover, the load in peak load period of working day is higher than day off but the load in off peak load period is not different. When compare the load profile with PV generator production, the load is 100% supplied by PV generator during 8 A.M. to 4 P.M. in working day and 8 A.M. to 5 P.M. in day off. Moreover, PV generator generates the surplus energy 169 kWh/day in working day and 232 kWh/day in these periods.