Fast power-flow solution by the method of reduction and restoration

The paper gives a fast power-flow-solution technique retaining only voltage-controlled busbars in the iterative process. Voltages are represented in rectangular co-ordinates, and the change in voltages from the assumed values is estimated in the iterative process. Power mismatches are computed only at two stages instead of at every iteration. After obtaining convergence, the original network is restored and the voltages of the load busbars are calculated. The essential features of the method are (a) only voltage-controlled busbars are retained during the iterative process, (b) a smaller-order Jacobian is used which is computed and inverted only once, thereby reducing the time of computation, and (c) on convergence, the system is restored to the original size, giving the voltage of all the busbars. This method is faster than other methods and can be conveniently applied to analysis and planning studies of large power systems.