The sort of fault diagnosis in large synchronous generators by analytic hierarchy process (AHP) method

Generators are the most important and valuable equipment in power systems. Internal faults not only damage the generator but also interrupt electricity generation and cause load rejection. If they are not detected immediately they spread, then repair becomes very long and tedious and the availability of the generator is lost. Unplanned repair costs of different parts of a generator and pertinent cost of generator outage during its effective life time is much more than the cost of detector equipment. Fault diagnosis in a generator is done by many methods some of which are on-line and others are off-line. Using the different equipments for fault diagnosis in a generator may be ideal at first glance, but because of equipment cost, unavailable technology, repair, maintenance and so on is not ideal (according to many power plants in Iran). Then the device which detects the most probable faults in order to reduce fault occurrence is very important. According to the above, information about fault occurrence in generators over ten years (1986-1996) are gathered by questionnaire. Then, the most probable fault in generators is made known by the AHP method.