WTR Compound
The breakdown test after this test with a certain pass level gives an estimate how the cable should perform during the entire life. It should be noted that during these tests only 10 m are tested and that longer cables have a lower break down value as mentioned in several publications. (ISEI 2006, JiCable 2019).
One way to have a water tree retardant cable is using a so-called water tree retardant XLPE compound, called TRXLPE. It should be noted that there is no definition and standard that defines these compounds. Using these compounds will increase the chance passing the test.
Also the semi-conductive compounds have an influence on the performance on these tests.
Another way to improve your chances is with the construction and processing of the cable. Several parameters should be controlled during the cable production in order to improve the electrical behaviour under wet conditions.
Eifelkabel has a solution with very low losses at high electrical field and 105 °C insulation temperature for cables passing even the highest demands in a wet ageing test. Detlef Wald is the chair of working group A13W which will revise the IEEE1407 guide and was member of Cigre B1-55, who wrote TB722.
