CONTROL STRATEGY FOR SVC DEPLOYED IN A DEVELOPING EHV TRANSMISSION SYSTEM

Static Var Compensators (SVC) are being increasingly employed in Power System mainly to control the voltage either by absorbing the reactive power or by supplying the reactive power to the system. SVCs provide solutions in Power System to a variety of problems inherent to the growth of any developing Power System in: - Effective voltage Control including control of temporary over voltages. - Increasing the power transfer capability. Increasing transient stability margin. - Damping of power oscillations. To derive the maximum benefits from SVCs while achieving the above functions, it is required that the control strategy for SVCs is specified keeping in view the prevalent system conditions during normal and contingent modes of system operation. This is of great concern in a growing EHV system where the variation in system configuration from worst network contingency to normal system operation to the planned configuration is very large. To meet these objectives it is necessary that the control strategy for SVC, particularly the under voltage strategy and the strategy during frequency excursions, is evolved for the system to which SVC is dedicated in a very careful manner. However, due to economic considerations it may not be possible to cater for all the contingencies. In those case a compromise is reached considering the probability of occurrence of such a contingency.