Automatic voltage control（AVC） system is used to adjust tap of power system transformer

to switch such reactive power equipment as capacitor and shunt reactor so to assure the minimum tap adjustment number

the most reasonable switching of capacitor and shunt reactor and achieve such overall object as qualified voltage and minimum grid loss. In this paper

the construction of AVC system for Chongqing grid

main control strategy and the setting principle of lock signal is introduced

and the reason of unsuccessful switching of capacitor bank by AVC is analyzed from such three aspects as switching fault of capacitor bank

allocation of capacitor bank and control strategy of AVC. Finally

some measures on improving the successful rate of capacitor rate by AVC are proposed.