An increased penetration of wind turbine generating systems into power grid calls for proper modeling of the systems and incorporating the model into various computational tools used in power system operation and planning studies. This paper proposes a simple method of incorporating the exact equivalent circuit of a fixed speed wind generator into conventional power flow program. The method simply adds two internal buses of the generator to include all parameters of the equivalent circuit. For a given wind speed, the active power injection into one of the internal buses is determined through wind turbine power curve supplied by the manufacturers. The internal buses of the model can be treated as a traditional P-Q bus and thus can easily be incorporated into any standard power flow program by simply augmenting the input data files and without modifying source codes of the program. The effectiveness of the proposed method is then evaluated on a simple system as well as on the IEEE 30- and 118-bus systems. The results of the simple system are also compared with those found through Matlab/Simulink using dynamic model of wind generating system given in SimPowerSystems blockset. (C) 2014 Elsevier Ltd. All rights reserved.