Accelerated aging of XLPE, EPR & HRPVC cables. 1

[dabhasker]

We are trying to determine the designed life of XLPE, EPR & HRPVC power cables. Is there a relationship between temperature & time ( Arrehenius curve)by which we can determine the designed life of subject cables by subjecting the cable samples to higher temperature and then by extrapolation. Are there any references which give the life of theses cables.

 

[jghrist]

The aging of extruded insulation is not as simple as with oil/paper insulation. I don't think you can come up with a mathematical expression like an Arrehenius curve. Accelerated life cable tests generally will use heat cycling and overvoltage stress, with the cables submerged in water. See:

Accelerated aging of extruded dielectric power cables. II. Life testing of 15 kV XLPE-insulated cables; Bernstein, B.S.; Thue, W.A.; Walton, M.D.; Smith, J.T., III;
Electr. Power Res. Inst., Washington, DC;
This paper appears in: IEEE Transactions on Power Delivery

Publication Date: Apr 1992
On page(s): 603-608
Volume: 7, Issue: 2
ISSN: 0885-8977
References Cited: 7
CODEN: ITPDE5
INSPEC Accession Number: 4171888


Abstract:
For pt.I see ibid., vol.7, no.2, p.596-602 (1992). Preliminary results are described in which 15 kV XLPE cables were subjected to accelerated aging tests under a variety of controlled voltage stress and thermal load cycle conditions, with loss of life being calculated for each set of conditions in terms of the geometric mean time to failure (GMTF). The relative influence of voltage stress and load cycle temperature are discussed. Accelerated aging results show a reduction in GMTF for 15 kV XLPE-insulated cables as the voltage stress or conductor load cycle temperature is increased in a controlled manner. The relative influence of voltage stress versus load cycle temperature can be compared. The GMTF increases more in going from 90°C to 60°C at constant applied voltage stress than in going from 4X to 2X rated voltage at constant load cycle temperature condition.

 

[alehman]

Take a look at IEEE and IEE journals. Many articles have been published on this subject. Water-treeing and how to simulate aging related to treeing has been researched extensively.

 

[dabhasker]

Thanks Jghrist & alehaman, I will check out the references furnished by you.

 

[ScottyUK]

ERA Technology in the UK used to have a very active Cables Group. Their published reports are available, for a fee naturally. I no longer have any contacts at ERA, but the switchboard phone number is (or was):

+44 1372 367000

They should be able to point you in the right direction.

 

[xabproject]

dabhasker,
CPRI Bangalore has done a great deal of good work in this connection. You will find the access also very easily.
Goodluck!

best regards