In this paper

the necessity to construct AVC（automatic voltage control） system in the power system of Tangshan is introduced

the actual application of AVC system in Tangshan power grid is studied

the problems existed in AVC operation are analyzed and corresponding improvement suggestions are raised.After implementation of AVC system

the most effective use of reactive power resources are achieved;the management of reactive power voltage of power network is really transitioned from traditional experience to intelligent management;the accurate and correct automatic control of network voltage is effectively achieved;and the supply of high-quality electric power to the user is ensured.