Your Experiences of PD On-site Measurement for MV Cables?

Hi fellows,

Do you have practical experiences of measuring Partial Discharges from medium voltage cables(6-35 kV), using inductive high frequency current transformer sensors over the cable groundings at the end of cable? In environmentals like powerplants, industrial etc. where the noise level can be huge.

Check f.e this :
https://www.omicronenergy.com/fileadmin/user_upload/pdf/literature/Monitoring-Solutions-Brochure-ENU.pdf

I have read many articles about it, but there are no clear limits of pC's of any kind of cables. Or well I have seen couple tables of PD's of XLPE cables, but they are too far away from each other so you can't really just choose one of them.

Ofcourse you can always compare the three phases to each other and try to find the weak ones, but I am interested in if someone have actually done these measurements and what are his/her thoughts about high pC-levels.

Also if You have done this, the question is: can it be seen from the PD patterns, is the PD coming from cable ending, joints, or is there probably electrical treeing or something else?

(like in generators you can localize the PD source in windings from PD patterns)

Pst. notice that I am not looking for corona scope measurements!)

got experiences?