10.4 Bushing hot collar test
The following picture illustrates measurement setup for hot collar test to measure insulation losses
of a small section of the bushing. This test is useful when the bushing is not equipped with a tap
electrode and can be used to locate probable cracks in porcelain or insulation problems.
For the test setup, at first, a conductive hot collar band must be fit tightly to the surface of bushing,
mainly near the top, then test cables must be connected according to the following picture.
For this test the UST A mode should be selected.
If the current or watts-loss is appreciably higher than normal, move the collar one petticoat down
and do another test. Repeat this procedure and move the collar as far down as necessary to
determine how far down the fault has progressed.
To Next Page
Loading...