Power Capacitors for AC Power System Application

Central Power Research Institute, Bangalore, is playing an important role in the development of the capacitor industry by providing required facilities for research, testing and evaluation of power capacitors. With the help of these facilities, all types of power capacitors, like all fi lm capacitors, composite dielectric capacitors, metallized fi lm capacitors, etc. are being tested and evaluated. In addition to facilities for routine and type testing of power capacitors according to the IS Standard, sophisticated and expensive equipment for conducting more stringent tests like Endurance test on fullsize capacitor units up to unit rating of 1 MVAr and partial discharge test based on advance acoustic emission technique are available in the Capacitors Laboratory of CPRI, Bangalore. Facilities for testing high voltage series capacitors have been developed including discharge current test, disconnecting test on internal fuses and cold duty test. In the fi eld of LV capacitors, special test facilities for chargedischarge and destruction test have been augmented to meet the requirements according to the revised IS:13341-1992. Test facilities are also available according to the UL safety requirements. Capacitor manufacturers in the country and from abroad are availing the facilities of CPRI. Experience of CPRI during testing of different types of LV and HV capacitors of unit rating ranging from 1 kVAr to 1118 kVAr for the last 10 years for will be covered in the paper. Some of the important issues like (a) factors infl uencing the capacitor losses, (b) infl uence of dissipation factor on the performance of LV capacitors during 1500 hours aging test, (c) performance of full - size HV capacitors under cyclic over voltage applications at different lower temperature limits, (d) operation of internal fuse, (e) testing of special capacitors for space applications, (f) factors infl uencing discharge current characteristics for series capacitors, and (g) acoustic emission technique as one of the NDT methods for performance evaluation, etc. will be discussed in the paper.