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Power Industry Asset Management Consultants
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Power Industry Asset Management Consultants
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The paper discusses power transformer condition assessment cost effective
methodology allowing ranking the transformer population and filter out
over 80-90%, which does not require special tests and complex maintenance
procedures.
Methodology based on transformer design review, operation condition review
and comprehensive oil analysis.
Key words: Power transformer- Design review, Oil analysis.
The maintenance policy for HV power apparatus is changing under
the pressure of economical considerations. Key utility aspects are long
term strategies
for system usability and reliability
require knowledge of usable service time and serviceability of the transformer.
Important factors are budget planning and pressure to postpone the cost
not only for replacement of unreliable units but also for major maintenance
procedures
that require equipment de-energizing and prolong non-availability.
Typical failure rate of power transformer is around 2%. It means that another
5-6% can be in a critical condition in terms of short-term reliability.
Among the aged population only 10-15%
are typically suffered from excessive deterioration and require special
procedures to prevent early end of life.
Condition –based ranking could be a proper solution to select weak components
in the transformer population [1]. It was shown that ranking may be performed
by means of determination of some critical parameters based on diagnostic
testing results (routine and special) and engineering analysis using design
tool and historical background of the units [2].
Latest developments of ZTZ-Service have shown that effectiveness of equipment
ranking can be significantly enhanced by means of implementation of condition-based
functional methodology [3,4].
This paper discusses diagnostic methodology based on transformer design
review, operation condition review and comprehensive oil analysis, which
allow effective ranking of the transformer population.