PD technology for on-line insulation testing in power generators / motors and experience in Iranian power stations

The requirement of any power generating utility is to achieve reliable and trouble free power generation in their facilities. Systems for on-line quality and reliability assessment of High Voltage power equipment have became very popular in recent years. By having access to power equipment while in normal operation, plant engineers have been able to avoid catastrophic in service failures, costly forced outages of power generators and associated equipment, as well as prolong significantly the life of the equipment. By early detection of developing problems on power systems, maintenance can be scheduled promptly and only when necessary. Planning of work and resources can be done well in advance, which will tremendously reduce the cost of such intervention. Also by perform ing test before and after repair it is easy to control the effectiveness of repair. On-line monitoring systems which are non destructive, reliable, quick and easy to use, have in fact become a kind of standard in many power utilities worldwide. A major problem in HV power equipment is electrical insulation. One online tests for the integrity of power equipment is thePD (Partial Discharge) test for electrical insulation. The PD test besides testing power generators and motors is also applicable for factory screening of stator bars, testing HV power cables and power transformers.