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Tan Delta VLF testing on new distribution system at 2400 volts

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    Tan Delta VLF testing on new distribution system at 2400 volts

    Brand new underground distribution system in small mountain village (currently running on overhead distribution, but will switch to new system soon we hope). Private Hydro electric. Operates at 2400V. New cable is all underground, 1/0 Copper, 5kV with tape shield, terminated in 200 amp Load Break Elbows into vaults, no vault lids or gear set yet. We meggered them at 5kV and they all held at over 20 Giga-ohms, before we put on the Load Break Elbows.

    Short runs of cable are about 250 feet, longest run is about 900 feet.

    We are not required to test these for "acceptance" as we did the work ourselves. But we do want to make sure it is all good before we do set lids and gear. We have onsite VLF and Tan Delta equipment by HVI.
    Questions: Which tests would you do (Megger, Tan Delta, VLF withstand), and why? Should we megger again now that the Load Break Elbows are on? How long would you hold the voltage at 5K? These cables are relatively short, how long should we hold if we do Tan Delta or VLF withstand?

    Thanks for the help!
    Last edited by PGates; 10-03-14, 08:45 PM. Reason: clarity