Maintenance; General; Service-Life; Inspection And Functional Testing - ABB VD4 Product Manual

Maintenance

8
Maintenance serves
operation and achieve the longest possible work-
ing life of the switchgear. In accordance with
DIN 31 051 / IEC 61208 it comprises the following
closely related activities:
Inspection: Determination of the actual condition
Servicing: Preservation of a functional condition
Repair: Measures to restore the functional
condition
8.1

General

Vacuum circuit-breakers are characterized by
their simple and robust construction. They have a
long life expectancy. Their operating mechanisms
have a low maintenance requirement, and the
interrupters are maintenance-free during their
working life. There is no adverse effect on the
vacuum, even from frequent switching of operating
and short-circuit currents.
The servicing intervals and scope are determined by
environmental influences, the switching sequences
and number of short-circuit breaking operations.
Note:
The following must be observed for all maintenance
work:
• The relevant specifications in section "Standards
and specifications"
• Notes on safety at work in section "Commis-
sioning/Operation"
• Standards and specifications in the country of
installation.
Maintenance work may only be performed by fully
trained personnel, observing all the relevant safety
regulations. It is recommended that ABB after-
sales service personnel should be called in, at least
during the performance of servicing and repair
work.
While the work is in progress, all supply voltage
sources must also be disconnected and secured
to prevent reconnection.
Note:
In order to prevent accidents (particularly injury to
hands!) extreme care should be taken during
all repair work on the operating mechanism,
especially with front plate removed.
The spiral spring in the spring energy storage
mechanism, for instance, retains a basic tension
which is independent of the charging and
discharging processes during switching, so as to
ensure correct function. This spring energy can
be inadvertently released if work is performed
incorrectly on the spring mechanism!
42
to ensure trouble-free

8.1.1 Service-life

Typical life-expectancies for VD4 circuit-breakers:
• Vacuum interrupter chambers: Up to 30,000
switching cycles, depending on chamber type
(see section "Permissible numbers of switching
cycles")
• Device: Up to 30,000 cycles under normal
operating conditions, depending on breaker
type, and given regularly and conscientiously
performed maintenance
• Withdrawable assembly: With careful operation
and appropriately performed inspection work,
up to 1000 movement operations can be
achieved.
See also IEC 60298
The service life data fundamentally apply to all
components which are not directly influenced by
the operator.
Components operated manually (movement of the
withdrawable part, etc.) may deviate.
8.2

Inspection and functional testing

8.2.1 Switching devices in general
• The proper condition of the switching device is
to be verified by regular inspection.
• The checks are to be performed in accordance
with BGV A3 standard.
• Inspection at fixed intervals may be waived if the
switchgear is permanently monitored by a
qualified personnel.
• The checks first and foremost comprise visual
examination
moisture and discharge phenomena.
• In unusual operating conditions (including
adverse climatic conditions) and/or special envi-
ronmental pollutions (e.g. heavy contamination
and aggressive atmosphere), inspection may
also be necessary at shorter intervals.
• Visual checking of the isolating contact system.
We recommend to turn alternately the contact
system in order to clean the inner contact points
of the contact system.
The contact points should be cleaned if signs of
unperminable overheating (discoloured surface)
are visible (see section "Repair")
• If an incorrect condition is found, appropriate
servicing measures are to be initiated.

8.2.2 Stored-energy spring mechanism

Functional testing of the operating mechanism is to
be performed:
• after 5000 operating cycles or
• during servicing work as set out in section
„Inspection, switching devices in general".
for contamination, corrosion,