Performance Analysis of Optimally Operated DOIG Based Stand-Alone Wind Power Generation System at Different Sites

An algorithm is developed for optimal sizing of wind driven stand-alone double output induction generator (DOIG). Nonlinear constrained optimization technique is used to trace the maximum power generated by the system for a given machine and converter rating. Both inequality and equality nonlinear constraints are considered. Among them the most significant one is the reactive power balance constraints, which is not often considered for stand alone systems. The problem is solved in MATLAB environment. The same algorithm is then used to accommodate different ratings of machines and converters to find the maximum powers as function of wind velocity, load power factor and component´s size. Weibull distribution is considered for modeling the wind velocity probability density function of seven Indian sites. The probability density of load power factor is considered to be distributed following Normal distribution. The joint probability of a particular velocity and a particular load power factor is calculated and used to measure the energy, captured by the system at a given site for different machine-converter combinations. The installation and O&M costs are considered to follow the present day trends. The proposed method finally finds the optimum combination of machine and converters (stator and rotor sides) to get minimum cost of energy. It is shown that the proposed wind energy conversion systems (WECS) can produce energy at a competitive low rate for moderately windy sites.