Megger DELTA4000, Instruction Manual, Page: 63 / 74

Performing Tests within Forms
AVTMDELTA4000-EN Rev 6 April 2018
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factor is pending the test voltage. In this situation a tip-up (step voltage) test
should be performed to verify and quantify the voltage dependence.
Bushing C1 Tests
If the transformer windings are terminated using condenser bushings, then
measurements of the C1 insulation on each bushing are generally made. The
bushing insulation C1 is internal and is the insulation between the bushing center
conductor and its test tap (capacitance tap). If a bushing does not have a test
tap, then the C1 measurement is not performed.
NOTE: These tests may be performed with the bushing shorting leads still in
place from the overall insulation tests. This allows all the high side
bushing C1 tests to be performed without having to move the HV lead
from bushing to bushing. It will still be necessary to move the Red lead
to the individual test taps for each test.
Test 11 - This is the test of the C1 insulation on the high side phase 1 bushing.
The HV lead is connected to the bushing top terminal and the Red lead is
connected to the bushing test tap. Test mode is UST-R.