Cable Test Voltage 3

Field test of a 132 kV cable?? I'd definitely get a recommendation from the manufacturer and follow that. Hi-pot testing of cable insulation is no longer recommended by IEEE. There have been several long threads discussing this issue on this forum. A search for Ben Lanz's posts should turn them up.

I am guessing 13.2kV is what he meant to type.

Specs
NETA MTS
IEEE 400

What type of cable? % insulation level?

Guess away - 132kV is a standard voltage in the UK and no doubt in parts of our former empire. For reference the common levels in this patch are 415V, 3.3kV, 6.6kv, 11kV, 22kV, 33kV, 66kV, 132kV, 275kV, 400kV.



----------------------------------

If we learn from our mistakes I'm getting a great education!

Weel I gues where you are located is an important thing to incluse when asking about standards to follow.

I search some couple of threads and several gurus suggest Partial Discharge test. Do you have any link on this for me to study further. Thanks

Where are you (Actually the cable) located? Are we talking 132kV? Are you able to shut down?

We do a ton of on line PD testing but not on 132kV in europe, however I do know someone who does.

My first question would be why you want to test it after 6 years? Has there been a failure and a repair, or are you wanting to do a maintenance test, or has there been a problem on a similar cable, and you want to prove that it is not a problem on this one?

If there is no suspected problem, then taking it out to do either a HVac or PD (or both) test on it is really a waste of time. If you want to do something easy, you may want to measure PD activity by clamping a high frequency CT around the cable screen earth connection. This will give you an indication as to any problems in the sealing end or possibly joints in the cable. If this shows up anything, then perform an offline test.

If you do have a problem in a similar cable, then you really need to assess whether a high voltage test will determine if the the same problem exists in this cable or not. Adding a PD measurement to this would be valuable as well. Be aware here too that if PD activity is present at service volts, you may be seeing a quite a substantial problem.

PD tests have their limitations, in that the discharge pulses will only travel so far in the cable and still be detectable due to the attenuation of the cable impedance, so you may not "see" all the discharges in the cable. Again, you must know what you are looking for, and the limitations of the particular tests that you employ, to know whether it is a realistic test, or whether you will waste you money.

So if after you work out what you really need, you decide on a HV ac test, then another reference is the values in IEC 60840. This has figures for tests after installation of cables in this voltage range, and usually works on 1.7Uo for up to 60 minutes (ie about 132kV phase to ground). This figure obviously only applies if your cable was purchased to this standard, and as DPC says, have a chat with the manufacturer about it first. Also, you may want to decrease the test voltage due to the cable system being aged somewhat. Again, it really depends on what you are trying to achieve in your test.

ausphil

Thanks everyone for responding. The work actually calls for a 132kV cable diverted to another location. This existing cable is 6900 meters long wherein it will cut and joined with a new cable route of the same size. A length of 4000m will be joined to the existing cable. the cable is a Cu/XLPE/Cu wire/Lead Sheath/HDPE. The test equipment that will be used is a Frequency Resonance High Voltage AC Test.

What is the Test Voltage to be applied? Are there any other test to be conducted that we should be aware of?

See previous post, and make it through to the last paragraph this time.

ausphil

Thank you very much ausphil and everybody for the technical guidance. I'll do my part to get the reference and coordinate with the manufacturer.