A critical analysis on wind farms has been carried out to improve the perfo
rmance and reliability of wind energy system. The effect of its improvement
has been studied with the Optimal Renewable Energy Mathematical (OREM) mod
el which is developed for sustainable generation in India. The performance
and reliability of the wind turbine generators have been evaluated in a dem
onstration windfarm (6 MW) in India. The windfarm is situated in Kayathar,
a village in the south of Tamil Nadu State. The average technical availabil
ity, real availability and capacity factor have been analysed from 1991 to
1995 and they are found to be 92%, 54% and 19% respectively. Fault analysis
for grid failures has been done using pareto analysis. The analysis indica
tes that when grid drop failures are reduced by 50%, the overall reduction
in the frequency of faults would be 35.2%, which is significant. The reliab
ility analysis has also been done for the wind turbine generator. The failu
re rate is high to an extent of 6.7 x 10(-5) h(-1) in the case of a yaw con
trol defect and the factor of reliability is found to be 0.5 at 10 000 h. T
he OREM model developed reveals that when the reliability factor of wind en
ergy system is improved from 0.5 to 0.9 then the utilisation of wind energy
would be increased by 82%. (C) 1998 Elsevier Science Ltd. Al rights reserv
ed.