Informatics Publishing Limited

Viswanatha C. ¹, Rakesh K. G. ²

Affiliations
1 Joint Director, DCCD, Central Power Researh Institute, Bangalore-560080, IN
2 Engineering Assistant, DCCD Central Power Researh Institute, Bangalore-560080, IN

Abstract

Current transformers are core of electrical systems functioning to provide required inputs for metering and measurement purpose. Generally the current transformers are tested for electrical integrity by way of di-electric measurements such as capacitance tan delta, partial discharge, accuracy and others. Although these tests fairly determine di-electric/insulation co-ordination of current transformer they do not reveal thermal condition of current transformers. In this study attempts are made to understand thermal integrity of current transformers by way of temperature measurements and temperature rise of primary and secondary winding which are main constituents of current transformers. The current transformers though are of different type such as winding, bar type, window. The thermal performance is equally important for all these types of current transformers. The general approach is to measure temperatures at accessible regions such as tank surface if it is live tank type current transformer and also at the axel points of protruding outside the tank which are internally connected to conductors. The temperatures before energizing of current transformer and after temperature rise test are measured by resistance method in accordance with international standards. In this work, temperature mapping at steady state for several current transformers of 200 kV rating have been studied in the light of IEC standards and results are more discussed and analyzed to determine the thermal condition of current transformers.

Keywords

Thermal Analysis, Current Transformer, Thermal Mapping, Temperature Rise, Instrument Transformer

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Viswanatha C. ¹, Vittal G. P. ², Mohanbabu V. ²

Affiliations
1 Author for correspondence HRT laboratory, DCCD, Central Power Research Institute, Bangalore - 560080, IS
2 HRT laboratory, DCCD, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Thermal performance has been the subject of studies for LV equipment since decades and continues to be the established practice to assess its continued usage of the equipment in service or installation in the case of newly designed equipment. The PDBP being core of the distribution network to deliver reliable quality power is investigated for its performance in ambient temperature and at elevated temperature. Although, the equipment behavior is known at ambient temperature, its performance at elevated temperature of 55˚C is seldom studied. Recently, the temperature in the globe is on the raise leading to global warming and in addition there is requirement in industrial applications and high temperate zones. The feasibility of electrical equipment in this elevated temperature condition is not known. In this context, the equipment has been subjected to laboratory studies. The data obtained showed the interesting results such as need of thermally endured materials in the configured system of the equipment. The operation of the equipment in elevated temperature will accelerate deterioration and reduction in the service life of the equipment. However, proper thermally endured components, thermal design of the equipment will ensure for the application of the equipment in the elevated temperature. The method of Temperature monitoring of the equipment by subjecting to service condition of operating temperature and current can be applied as a means to study the thermal performance of equipment. These aspects of the experimental method, the results obtained at ambient and elevated temperature are discussed and investigated in this research work.

Keywords

Thermal, elevated temperature, Distribution Board, ageing, insulators, Temperature rise.

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Vani Vijay ¹, Giridhar Kini P. ², Viswanatha C. ³, Jothibasu S. ⁴

Affiliations
1 Energy Efficiency and Renewable Enenrgy Division, Central Power Research Institute, Bangalore- 560080, IN
2 E&E department, Manipal Institute of Technology, Manipal 576104, IN
3 Diagnostics Cables and capacitors Division, Central Power Research Institute, Bangalore-560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore -560080, IN

Abstract

Back to Back converters are commonly used converters in many ac to ac conversion applications. Even though Converters without intermediate energy storage element are developed, Those with DC link capacitors still continue to be most popular due to the inherent advantages. The performance of such converters is affected by the operation of DC link capacitors used. This paper gives a detailed study of various types of back to back converters and considerations in DC link capacitor design and selection. A MATLAB program is also developed to analyze the effect of RMS (Root mean Square) ripple current and consequent effect on the life of the DC link capacitors in Voltage link back to back converters.

Keywords

Back to back converters; matrix converter, DC link capacitors.

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