Maintenance - ABB VD4G-25 Installation And Operating Instructions Manual

V D 4 G I N S TA L L AT I O N A N D O P E R AT I N G I N S T R U C T I O N S
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9. Maintenance

The purpose of maintenance is to keep the
apparatus in a good working condition for as long
as possible. The following operations must be
performed in accordance with the specifications
given in standards IEC 61208 / DIN 31 051:
Inspection:
Servicing:
Repair:
9.1. General information
Vacuum circuit-breakers are characterized by
simple, sturdy construction and long life.
The operating mechanism requires functional
inspections and maintenance if it is to remain
operative throughout its forecast life cycle (see
sect. 9.3.2.).
The vacuum interrupters are maintenance-free for
their whole operating life.
Vacuum interruption does not produce harmful
effects even when there are frequent interruptions
in the rated and short-circuit current.
Interventions during service and their purpose are
determined by the ambient conditions, the
sequence of operations and shortcircuit
interruptions.
Note
Comply with the following regulations for maintenance work:
• the relative specifications given in the chapter on "Standards and Speci-
fications";
• the labor safety regulations in the chapter on "Putting into service and
operations";
• the standards and specifications in force in the country where the appa-
ratus is installed.
Maintenance operations must only be carried out by
personnel who have been trained and who comply
with all the safety regulations. In addition, it is
advisable to have ABB personnel at least check
performance during service and carry out any
repairs required.
Cut off the power supply and ensure the apparatus
is in a safe condition during maintenance.
9.1.1. Operating life
The operating life expectancy of VD4G circuit-
breakers is as follows:
• vacuum interrupters: up to 30,000 mechanical
operations
• actuator and transmission system: up to 30,000
operations, under normal operating conditions,
depending on the type of circuit-breaker and with
regular maintenance (see sect. 9.3.2.);
Finding out the actual conditions
Measures to be taken to maintain the
specific conditions
Measures to be taken to restore the
specific conditions.
Before proceeding with any operation,
make sure that the circuit-breaker is
open, with the spring discharged and
that it is not powered (medium voltage
circuit and auxiliary circuits).
• racking-in/out can be performed up to 1000 times
if the operations are carried out correctly (as
required by standard IEC 60271-200);
• the operating life data are basically applicable to
all components that are not directly influenced by
the operator's tasks. The behavior of components
operated in the manual mode (moving
components of disconnectable parts, etc.) can
vary.
9.2. Inspections and functionality
tests
9.2.1. Pole and conductive parts
• Regularly inspect the conditions of the conductive
parts.
• Inspection at fixed intervals can be avoided when
the apparatus is permanently under the control of
qualified personnel.
• Firstly, the assessments must include visual
inspection to check for any contamination, traces
of corrosion or electrical discharge.
• Perform more frequent inspections when there
are unusual operating conditions (including severe
climatic conditions) and in the case of
environmental pollution (e.g. high level of
contamination or an aggressive atmosphere).
• Visual inspection of the isolating contacts. If there
are tulip contacts, remember to turn them
alternately in order to keep the internal surface of
the conduction areas clean. The contact areas
must be cleaned when there are signs of
overheating (discolored surface) (also consult the
Repairs section).
• Perform servicing if the conditions are abnormal
(see Servicing sect.).
9.2.2. Stored energy spring operating mechanism
Run a functional test on the operating mechanism
test at least every 5,000 operations or 5 years, or as
part of the normal maintenance operations
described in sect. 9.2.1.
Perform the following operations before conducting
the test:
• if the circuit-breaker is withdrawable, it must be
brought to the isolated for test position.
• for fixed circuit-breakers: shut off the power
supplied to the medium voltage circuit.
Note
Isolate the work area and make it safe by following the safety regulations
specified in standards IEC/DIN VDE.