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9. Maintenance
9.1 Maintenance strategies
Preventive maintenance
is maintenance carried out at predetermined
intervals or according to prescribed criteria,
aimed at reducing the failure risk or performance
degradation of the equipment. This method is
based on scheduled activities performed on the
out-of-service equipment including: visual
checks, apparatus cleaning, mechanical
components lubrication, worn parts replacement
and routine tests.
Risk-based maintenance
is maintenance carried out by integrating
analysis, measurement and periodic test
activities with standard preventive maintenance.
The gathered information is viewed in the context
of the environmental, operation and process
condition of the equipment in the system. The
aim is to perform the asset condition and risk
assessment and define the appropriate
maintenance tasks. Please refer to next chapters
for details of preventive and risk-based
maintenance programs.
WARNING - Always follow 7 safety
steps:
• Clearly identify the work location
• Disconnect and secure against reconnection
• Protect against any other live parts
• Take special precautions when close to bare
conductors
• Check the installation is dead
• Carry out earthing and short circuiting
• Issue a permit to work
9.2 Preventive maintenance
Maintenance serves to preserve trouble-free
operation and achieve the longest possible
working life of the switchgear. It comprises the
following closely related activities:
Inspection: Determination of the actual
condition.
Servicing: Measures to preserve the specified
condition.
Repair: Measures to restore the specified
condition.
Note:
When carrying out all maintenance work, the
regulations in the country of installation must be
strictly complied with. Maintenance work may
only be performed in a careful manner by trained
personnel familiar with the characteristics of the
individual switchgear, in accordance with all
relevant IEC safety regulations and those of other
technical authorities, and with other over-riding
instructions. It is recommended that ABB service
personnel be called in to perform the servicing
and repair work detailed below. The inspection
and servicing intervals for some of the equipment
/ components (e.g. parts subjects to wear) are
determined by fixed criteria, such as switching
frequency, length of service and number of short-
circuit breaking operations. On the other hand,
for other parts the length of the intervals may
depend, for example, on the different modes of
operation in individual cases, the degree of
loading, and also environmental influences
(including pollution and aggressive air).
The following operating instructions must also be
followed, together with this instruction manual in
the individual cases concerned:
• Vacuum circuit-breaker
• Vacuum circuit-breaker with magnetic
actuator
• Gas circuit-breaker
• Vacuum contactor
• Switch-disconnector
• Motor operating device dedicated for
medium voltage switch-disconnectors,
disconnectors and earthing switches
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