For the purpose of taking on-line detection of insulation performance for power equipment in time and effectively and reducing power off time and assuring safe operation of power grid

a new type of on-line detection system for measuring dielectric loss and capacitance of capacitive equipment is introduced in this paper. The capacitive equipment is measured and monitored by way of high accuracy clamp current transformer and voltage isolating coil. Such system not only possesses the function of electromagnetic interference immunity

but also adopts relative and absolute measurement methods for monitoring. It is shown by the test result that such measurement system has obtained perfect measurement result at different conditions.