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6.3. Inspection
General instructions
Where necessary, the working area must be isolated
and secured against accidental re-connection before
the inspections are performed, in accordance with the
“Safety regulations” specified by the IEC standards and
corresponding national standards. Switchgear conditions
must be monitored by regular inspections. Under normal
operating conditions, inspections should be carried out once
every five years by suitably trained professional electricians.
Instructions
Perform the following inspections:
– Visually check for dirt, corrosion and moisture.
– Check for effects of high temperature on the main circuits.
– Check for traces of partial discharges on insulating
components.
– Check for traces of current leakage on insulating
components.
– Visually check the surfaces of the contact systems
- The contact areas must be cleaned if signs of overheating
are visible (discoloured surface).
– Check the general condition and lubricate (Klüber NCA 52)
the earthing switch contacts.
– Check the operating pressure of the GSec if the gas (SF6)
monitoring device is available.
The inspection must also include checking correct
mechanical/electrical operation of the following switching
devices:
– 1S and 2S operating mechanisms;
– interlocking devices;
– protection devices;
– signalling devices;
– accessories and auxiliary devices (e.g. earthing switches).
Partial discharge must not occur on the surfaces of the
equipment in the presence of operating voltage. This can,
for example, be detected by characteristic noises, a clearly
perceptible smell of ozone, or visible glowing in the dark.
Repairs
Appropriate servicing or repair measures must be taken if
abnormal conditions are detected.
6.4. Servicing
Instructions
If the need for servicing measures is established during the
course of an inspection, proceed as follows:
1. Tighten all electrical connections to the correct torque
value.
2. Clean all parts (disconnectors, release mechanisms,
motors, etc.) with a vacuum cleaner and visually inspect
them. Clean all surfaces in general:
- Lightly settled dry dust deposits: clean with a soft dry
cloth.
3. Perform an closing/opening operation on all switch-
disconnectors, including the earthing switches.
4. Connect the auxiliary control voltage, but make sure that
no remote signals can activate the components. Perform
one electrical operation sequence on all motor-operated
devices and tripping mechanisms.
5. Clean the insulating materials of the GSec switch-
disconnector and and busbars with a clean, soft, dry cloth.
Remove all ingrained dirt, such as sticky or greasy stains,
using a cloth and a mild alkaline detergent. Wipe with
a damp cloth using clean water and thoroughly dry the
surfaces. Clean inside the cable compartment in the same
way (bottom of GSec switch-disconnector, instrument
transformers, busbars and circuit-breaker).
6. If necessary, clean and grease (Klüber NCA 52) the
earthing switch contactor, the blade and operating
mechanism.
NOTE
Under abnormal operating conditions
(including adverse cklimatic conditions)
and/or particular environmental conditions
(among which, heavy pollution and aggressive
atmosphere), inspection at shorter intervals
may be necessary.
NOTE
Should partial discharges occur as a result
of condensation, application of a thin layer
of silicone over the affected surface is
often effective as a temporary remedy. It is
advisable to ask the ABB after-sales service
department for advice regarding permanent
solutions to this uncommon type of problem.
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