  Voltage deviations occur frequently in power systems. If the violation at
some buses falls outside the prescribed range, it will be necessary to correct
the problem by controlling reactive power resources. In this paper, an optimal
algorithm is proposed to solve this problem by identifying the voltage buses,
that will have a maximum effect on the affected buses, and setting their new
set-points. This algorithm is based on the Eigen-Value Decomposition of the
fast decoupled load flow Jacobian matrix. Different Case studies including IEEE
9, 14, 30 and 57 bus systems have been used to verify the method.
