Search

The variation in daily environmental conditions has a notable effect on the thermal performance of the electrical machines, especially power transformers. The objective of this paper is to see the effect of solar radiation and wind flow external to the outdoor operating power transformers. The research work in this field involves the development of computational thermal models based on conventional International Electro-technical Commission (IEC) loading guide using appropriate software tools in order to determine the hot spot temperature. These thermal models are then modified by incorporating the effect of solar radiation and wind flow. The proposed method is validated using the operational data gathered from a 500MVA power transformer located at 400kV Grid Substation, Kankani, Jodhpur (Rajasthan, India). The comparative study between the conventional and modified thermal models helps in the reliable operation of power transformer and optimizes the use of forced cooling arrangements. [ABSTRACT FROM AUTHOR]

As the population of transformers in service increases and their operating time extends, much attention has been focused on their availability and reliability. However, insufficient research work concentrates on how to evaluate transformer's aging condition, although huge progress has been made on the techniques of fault diagnosis and condition assessment of transformer in past decades. This paper presents the concept of Aging Index (AI), which is a practical tool that combines the results of routine inspections, and site and laboratory testing to estimate the aging condition of oil-immersed transformers. Further, frequency domain spectroscopy (FDS) as a novel non-destructive testing technique to estimate remained life expectancy is included in aging evaluation system. Moreover, a software system based on transformer's electrical and thermal parameters is developed correspondingly, by using a multi-parameters analytic approach. This system would dedicate to decision-making and replacement planning and has good application prospects. [ABSTRACT FROM AUTHOR]