The development of a variable-frequency series resonant test set for after-laying tests on XLPE cables

The first 132 kV XLPE cable in South Africa was installed in 1975/76 at Boksburg near Johannesburg. As a result of the experience gained in this plant, which was commissioned in 1979, it was decided at the planning stage of a second similar installation to purchase a fully type tested system of cable and accessories from one manufacturer and to carry out an AC after laying test. A transportable series resonant AC test set was purchased which operated at 50 Hz and was capable of testing up to 2 km of 132 kV cable at twice working voltage. Each 132 kV cable circuit on the second plant was tested at 140 kV, the highest voltage the manufacturer of the SF₆ switchgear would allow. Each circuit was tested for a period of 15 minutes. No failures occurred in test and there have been no failures of either cable or accessories since the plant was commissioned in 1981