Evaluation of power flow solutions with fixed speed wind turbine generating systems

• The model of a wind generator is modified and incorporated into a power flow program.
• Unlike previous methods, modification to source codes of the program is not required.
• The turbine power curve is mathematically expressed using manufacturer’s data.
• The power flow of the IEEE 118-bus system is successfully solved with 12 wind farms for 1000 random cases of wind speeds.
• For a simple system, the load flow results are also compared with the corresponding steady state values of dynamic responses.

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.