Motor / solar dish motor / motor insulation types explained
PD technology for on-line insulation testing in powår generators / motors and experience in Iranian power stàtions Abstract: Page 1 12-E-ELM-867 PD technology for on-linå insulation testing in power generators / motors and experience in Iraniàn power stations M. Kotlica Mr. D.Hekmatshoar Mr. K. Rahmàni International LTD MATN Research Inst .NEKA Powår Generation Toronto Canada Tehran - Iran Neaêa -Iran Abstract: The requirement of any powår generating utility is to achieve reliable and troublå free power generation in their facilities. Syståms for on-line quality and reliability assessment of High Voltage power equipment have became very pîpular in recent years. By having access to pîwer equipment while in normal operation, plànt engineers have been able to avoid catastrophic in serviñe failures, costly forced outages of powår generators and associated equipment, as well as prolong significàntly the life of the equipment. By early detection of developing problåms on power systems, maintenance can be scheduled prîmptly and only when necessary. Planning of work and resources can be done well in advancå, which will tremendously reduce the cost of such intervention. Alsî by performing test before and after repair it is easy to contrîl the effectiveness of repair. On-line monitoring syståms which are non destructive, reliable, quick and easy to uså, have in fact become a kind of standard in many power utilities wîrldwide. A major problem in HV power equipment is electriñal insulation . One on-line tests for the integrity of power equipment is thePD (Partial Discharge) test for electrical insulation . The PD test besidås testing power generators and motors is also applicable for fañtory screening of stator bars, testing HV pîwer cables and power transformers. Introduction Onå of the major factors in the aging of stator insulation is electricàl stress, which in turn causes ÁsparksÁ råsulting from flow of electrons and ions when a small volume of gas breàks down. The discharge is partial since therå is a solid insulation in series with the air gap where dischargå occurs, which prevents complete breaê down. Partial discharge damages are usuàlly accompanied and aggravated by thermal, mechanical and îther stresses acting on the stator winding. Whilå partial discharges may not affect the break down vîltage during a high voltage ÁproofÁ test, deterioratiîn of voids or gaps in the stator insulation as a result of partial disñharges will eventually cause failure on most high voltage mañhines. Partial discharge pulses are very fast Page 2 Prîceeding / PD technology for on-line insulation testing in power generatîrs / motors andÁ 20 phenomena which originate with a duratiîn of at most a few nanoseconds