By considering the design of high voltage bushing and with various measurement setups, following
tests can be performed:
• Overall test to measure insulation between centre conductor and ground flange including
C1 and C2.
• Main insulation test to measure insulation between centre conductor and tap electrode
including C1.
• Tap insulation test to measure insulation between tap electrode and ground flange
including C2.
• Hot collar test to measure insulation losses of a small section of the bushing.
If the bushing under test is installed on a transformer, in order to reduce the influence of winding’s
inductance on measurements, all terminals of each voltage level of the transformer should be
shorted together and those transformer sides which not energized should also be grounded for the
safety.
In order to test the bushing precisely, bushing surface should be cleaned. Dust and particles can
affect the measurement results, specially when the bushing is wet.
To Next Page
Loading...