MV Cable insulation testing
MV Cable insulation testing
(OP)
What testing method for MV cable insulation do you thing is more reliable? A tan delta that gives a general quality of insulation for entire cable plus a pd test? Or tan delta plus VLF hipot test? I am looking to find the best way to do cable insulation testing, and I need a method that can tell me with some time before if a cable is near fail or not, and if is possible, where weak point are. Unfortunately, in my opinion, to do just a insulation resistance is not enough. And it will be better if testing method will not produce fail, or to make a bigger damage to the cable, which I can't tell for method I write above.
Thank you
Thank you






RE: MV Cable insulation testing
RE: MV Cable insulation testing
To determine the health of MV cable insulation may require that different tests be performed. It depends on how important the cable is TO YOU and how much money YOU are willing to spend to find out.
Its not about the technology its about the money. Its always about he money.
If someone could tell you with absolute certainty the present condition and expected life expectancy of your cable run would you pay them $100,000? $50,000? $10,000?
Maybe. Maybe not. Thats your call
(My apologies to the OP, long day)
RE: MV Cable insulation testing
A VLF Withstand test will stress the cable and intentionally cause failure where the insulation, or more likely, splices and terminations, are weak. It does not harm good insulation nor does it aggravate defects that do not start partial discharge under the test voltage. Simple pass/fail hipot, but VLF AC.
VLF Tangent Delta measures the overall degradation in the cable from one end to another. It is is best used when testing many cables and using the results to compare and prioritize for replacement and or silicon injection, or to determine what other tests may be valuable.
VLF Partial Discharge testing shows the location, severity, and the inception and extinction point of PD. It is a good test but not right for may situations. It is the most expensive and interpretive test of all. It is worthwhile in some instances. Don't let PD testing service companies try to tell you it is the only thing that works and everything else is no good. All three are effective but provide different info.
Know what you want from your tests and what repairs or replacements you are prepared to perfrom.
RE: MV Cable insulation testing
If you know other test with better results that can be perform to evaluate life expected of a cable (diferent tipes, diferent insulation- EPR, PVC, CSPE, XLPE), I'll appreciate your advice.
Thank you