Possibilities of control of reactive power flow in polish power system

Excessive reactive power flows are an important problem in a power system. Optimization of reactive power flows in the system allows reducing them. This paper deals with optimization of reactive power flows in the national power system. Effects of two variants of this optimization are presented. One of them is when voltage magnitudes at generation nodes, on-load tap changer positions, and reactive powers of compensators, which already exist in a power system, are control variables. In the second variant, one takes into account such control variables as in the first variant and also possibility of injection of reactive power at each node where it is possible. In that way, limit capabilities of modification of reactive power flows in the national power system are determined. In the paper, effects of optimization in each of the mentioned variants are analyzed. Particular attention is paid to comparison of those effects.