Partial Discharge Meter - Problem

Hi,

We are using PD tester for our application. While measuring the component(Current transformer) we found some variation in the readings of withstanding voltage from time to time.

This will put ourselves in a confused manner.

Details of PD tester:

Make: MWB,

Procured :2007

We didn't calibrate the PD unit still..(If any calibration centre is avail in india -Pls give the details)

Need your advice to come out from the above setback. If you need any more details reg the equipment pls feel free to contact us..