ABB GSBK 170, Руководство по установке и обслуживанию

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Installation and maintenance guide
1ZSC000563-AAB EN, REV. 6, 2019-09-12
4. Connect the measuring equipment.
1. Connect the low voltage cable to the stud (1).
2. Connect the high voltage cable to the
outer terminal.
3. Connect the ground cable to the bushing
flange (3).
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5. Measure the capacitance (C
1
) between the outer terminal and the stud (1).
• Record the capacitance (C
1
) for future reference.
NOTE!
Refer to the table for the nominal capacitance (C
1
), Nominal capacitance, page 48 .
6. Measure the capacitance (C
2
) between the stud (1) and the flange.
• Record the capacitance (C
2
) for future reference.
7.
Measure the dissipation factor:
1. Start the measurements with a low sensitivity setting on the measuring bridge.
2. Gradually increased the sensitivity setting on the measuring bridge to the highest possible.
3. Calculate the dissipation factor with the correction factor, refer to Dissipation factor, tan δ,
page 49 .
NOTE!
In some cases, external interference can make it difficult to set the measuring bridge
to zero.
8. Install the cover (2).
CAUTION!
The voltage tap is not self-grounding!
The bushing can be destroyed if the voltage tap is not grounded. Because the capacitance
(C
2
) is usually relatively small, the voltage tap must never be open-circuited when applying
a voltage to the bushing. It must always be grounded or connected to an external
impedance.
CAUTION!
Do not energize the bushing without the cover or a test adapter installed. The cover
connects the outermost conductive foil to ground and will prevent damage to the bushing.
CAUTION!
Make sure that the cover is correctly installed with the O-ring in place, when the bushing is
not in use. The purpose is to prevent dust and water from entering the tap.