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9. Maintenance
The maintenance operations are aimed at keeping the apparatus in
good working condition for as long as possible.
In accordance with what is specified in the IEC 61208 / DIN 31 051
Standards, the following operations must be carried out.
Inspection:
Finding out the actual conditions
Overhauling:
Measures to be taken to maintain the specific condi-
tions
Repairs:
Measures to be taken to restore the specific conditions.
9.1. General
Vacuum circuit-breakers are characterised by simple, sturdy construc-
tion and a long life.
The operating mechanism is maintenance-free for its whole operating
life, and only requires functional inspections (see par. 9.2.2.).
The vacuum interrupters are maintenance-free for their whole operating
life.
Vacuum interruption does not produce any harmful effects even when
there are frequent interruptions at the rated and short-circuit current.
The interventions during service and their aim are determined by the
ambient conditions, by the sequence of operations and by the short-
circuit interruptions.
Note
Respect the following Standards for maintenance work:
– the relative specifications given in the chapter on “Standards and
Specifications”;
– work safety regulations in the chapter on “Putting into service and
operations”;
– standards and specifications of the country where the apparatus is
installed.
The maintenance operations must only be carried out by trained per-
sonnel and who follow all the safety regulations. Furthermore, it is advis-
able to call on ABB personnel, at least in cases for checking the per-
formances in service and for repairs.
Cut the power supply off and put the apparatus under safe conditions
during the maintenance operations.
Before carrying out any operations, check that the circuit-
breaker is open, with the springs discharged and that it is
not supplied (medium voltage circuit and auxiliary circuits).
9.1.1. Operating life
The operating life expectancy for the VD4 circuit-breakers is as follows:
– vacuum interrupters: up to 30,000 operations, according to their type
(see par. 7.2.3. Trip curves).
– actuator and transmission system: up to 15,000 operations, under
normal operating conditions, according to the type of circuit-breaker
and with regular maintenance.
9.2. Inspections and functionality tests
9.2.1. Interruption devices in general
– Check the conditions of the interruption devices with regular inspec-
tions.
– Inspection at fixed intervals can be avoided when the apparatus is
permanently under the control of qualified personnel.
– The checks must, first of all, include visual inspection to check for
any contamination, traces of corrosion or electrical discharge phe-
nomena.
– Carry out more frequent inspections when there are unusual operat-
ing conditions (including severe climatic conditions) and in the case of
environmental pollution (e.g. high level of contamination or an atmos-
phere with aggressive agents).
– Visual inspection of the isolating contacts. It is recommended to turn
the contact system alternately in order to keep the internal surface of
the contact areas clean. The contact areas must be cleaned when
there are signs of overheating (discoloured surface) (also see Re-
pairs par.).
– In the case of abnormal conditions, take suitable overhauling meas-
ures (see Overhauling par.).
9.2.2. Stored energy operating mechanism
Carry out the functional test of the operating mechanism after 5,000
operations or after 4 years.
Before doing the test, open the circuit-breaker and de-energise the
medium voltage circuit.
Note
Insulate the work area and make it safe, following the safety regulations
specified in the IEC/DIN VDE Standards.
Functional test
– With the circuit-breaker not connected to the load, carry out a few
opening and closing operations.
– If provided, cut the power supply to the spring charging motor off.
Discharge the springs by closing and opening the circuit-breaker by
means of the closing and opening pushbuttons.
– Visually inspect the lubrication conditions of the jaw isolating con-
tacts, of the sliding surfaces, etc.
– Check correct electrical and mechanical operation of the various
devices, with particular attention to the interlocks.
– The screws and nuts are tightened in the factory and correct tighten-
ing is marked with a coloured mark. No further tightening operations
are foreseen during the operating life of the circuit-breaker. However,
following any interventions, should it be necessary to retighten the
screws or nuts, it is recommended to keep to the values indicated in
fig. 11.
– Check lubrication of the main actuator lever roller bearings (see de-
tails A of fig. 12): it is advisable to lubricate with a few drops of SAE
80W/90 type oil, using a special oiler.
Proceed as follows:
– remove the circuit-breaker screen
– charge the operating mechanism springs and lubricate the right-hand
bearing (circuit-breaker seen from the front)
– close the circuit-breaker and lubricate the left-hand bearing (circuit-
breaker seen from the front).
9.2.3. Circuit-breaker pole
No other check except what has already been specified in par. 9.2.1. is
necessary.
9.3. Overhauling
9.3.1. Interruption devices in general
Should it have been necessary to clean the devices during the inspec-
tions, according to what is specified in par. 9.2.1., use the following
procedure:
• insulate the work area and make it safe, following the safety regula-
tions specified in the IEC/DIN VDE Standards;
• general cleaning of the surfaces:
– dry and eliminate light deposits of dirt with a soft dry cloth;
– more resistant deposits of dirt can be removed using slightly alka-
line domestic type detergent or Rivolta BWR 210 type detergent;
• cleaning insulating surfaces and conductive parts:
– light dirt: with Rivolta BWR 210 detergent;
– resistant dirt: with cold detergent type 716.
After cleaning, rinse thoroughly with clean water and dry carefully.
Note
Only use detergents without halogens and never 1.1.1-trichloroethane,
trichloroethylene or carbon tetrachloride!
9.3.2. Actuator and transmission system
Circuit-breakers up to 31.5 kA
Complete replacement must be carried out after 15,000 operations for
the actuator (trip box), for the shock-absorber and for all the other
components of the transmission system (shaft, main levers, locking
rings, etc.).
Note
Dismantling and replacement of the operating mechanism (trip box) can
only be carried out by ABB personnel or by skilled and specially trained
personnel, particularly for the necessary adjustments.
– the VIDAR vacuum tester, made by the company Programma Electric
GmbH, Bad Homberg v.d.H.
