Secondary voltage control of power grid using voltage stability index and voltage control areas

This paper presents secondary voltage control of power grid using identification of voltage stability index and voltage control areas. Unlike, the traditional secondary voltage control in North America performed directly by switching capacitor banks and other reactive power sources, in the proposed approach generators are chosen first to perform secondary voltage control. The participation of generators in secondary voltage control increases the utilization of reactive power capability of generators as well as decreases the requirement of additional reactive power sources. To perform the control, the power grid is divided into voltage control areas using reactive power sensitivity method. A new technique of secondary voltage control with stability index is presented using vulnerability test considering all buses instead of just the pilot bus. The method is implemented on IEEE 39 bus system for secondary control when subjected to a disturbance and the simulation results are presented.

I. Introduction

Modern power grid characterize integration of distributed resources and growing consumer demand. This change causes increased system stress as grid operators have strong economic incentives to operate networks close to their physical limits [1]. When these physical limits are approached or breached, power systems can experience network-wide failure termed voltage collapse. Voltage collapse is initiated from the local phenomenon of progressive decrease of voltage in buses which is known as voltage instability. This is one of the major reason leading to system blackout. A blackout is a condition where a major portion or all of an electrical network is de-energized resulting in loss of electric supply to the affected customers.