The most of high voltage concentrating workless compensation equipments used for the power supply system in China are switched by manual operation,by which switching in can not be obtained in time at need of compensation,and switching off can not be done in time when overcompensating,so the roles in increasing the power factor and decreasing the electric energy have not been played.In order to well improve the quality of power supply and operate as economically,the controlling mode has been changed to make these equipments switch automatically in due time so that the efficiency of power supply system is brought to ful play.