Round table -- Condition based maintenance

Conference · Wed Jul 01 04:00:00 EDT 1998

OSTI ID:20018893

Wallis, D

The rapid development of gas turbines for power generation has curtailed the development of ever larger hydrogen and water cooled generators and an increased emphasis has been placed on the development of air cooled generators. This type of generator is particularly attractive because air cooling represents the simplest design, requires no ancillary equipment and incurs the lowest operating and maintenance effort. However, long term operation of these highly rated generators is extremely limited. Of particular concern is the performance of high voltage air cooled stator windings. The life of stator windings is a major factor in the life of an electrical machine and the condition of the electrical insulation in these windings is a critical determinant of life expectancy. High-voltage insulation in motor and generator stator windings gradually deteriorates due to mechanical, thermal, electrical and environmental stresses. It is therefore vital to ensure that any deterioration is detected at an early stage so that remedial action can be taken. If insulation failure occurs it often takes months to rewind the machine. With the need to ensure a high availability for this new generation of air cooled machines associated with dramatic reductions in Engineering staff following privatization of the UK Electricity Supply industry an optimization of the historic test and monitoring methods required. This has resulted in a reduction in the number of ``routine'' tests and the adoption of ``on-line'' and ``off-line'' monitoring techniques that clearly identify the critical items of plant. The application of partial discharge monitoring, generator condition monitors and condition based maintenance routines for critical auxiliary plant are now all employed to ensure the maximum availability of plant at the minimum cost.

• Research Organization: National Power plc (GB)
• OSTI ID: 20018893
• Report Number(s): CONF-9806214--
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
20 FOSSIL-FUELED POWER PLANTS
AVAILABILITY
ELECTRIC GENERATORS
ELECTRICAL INSULATION
GAS COOLING
GAS TURBINE POWER PLANTS
PERFORMANCE
SERVICE LIFE
STATORS
THERMAL EFFICIENCY