Beginning from pre-arcing between the electrodes during breaker making the short-circuit process

this physical process is discussed. The trigger characteristics of triggered spark gaps and of triggered vacuum switch are compared

and a synthetic making circuit at full-rated voltage is presented. The control of the phase of applied voltage

and the demand of the phase difference between applied voltage and making current in synthetic making test under full-rated voltage an- provided. The strategy and the main factors effecting controlling accuracy are also analyzed.