A solar energy is most popular renewable energy source which can reduce usage of fuel in thermal generation and impact on environment. The solar energy is a clean and sustainable source. This paper proposed method of finding optimal locating and sizing of PV solar farm on the power system with minimize fuel costs by considering solar radiation in each location of solar farm. The bees algorithm (BA) is used to minimize fuel cost of thermal units by changing location and varying sizes of solar farm with security constraints of power system and solar radiation. IEEE 30 bus test system is used to verify the proposed method. The results show that the proposed method found the optimal position of solar farm with minimum economic cost

One important factor that makes the variations of electric current produced from solar cells (Ipv) is the variability of the weather conditions of the day. The one year experiment from January to December 2012 had been set up. The experiment of the comparison of the weather data satellite images and the different current (Ipv_d) was obtained from daily Ipv. The results illustrated that there were 4 major types of the relationship between the Ipv_d and weather conditions; 1) Low Ipv_d at around 2000 mA with low perturbations would correspond to the clear sky condition. 2) Perturbation of Ipv_d in some periods would correspond to the cloudy condition. 3) High perturbations of Ipv_d for all day long would relate to the rainy – cloudy condition. 4) High Ipv_d at around 4000 mA with low perturbations would relate to the cloudy condition all day long.