Transformers are regarded as crucial components in power systems. Due to market globalization, power transformer manufacturers are facing an increasingly competitive environment that mandates the adoption of design strategies yielding better performance at lower costs. In this paper, a power transformer design methodology using multi-objective evolutionary optimization is proposed. Using this m...

We present the conditions in which a toroidal type, line frequency, power transformer can yield reduced stray magnetic field, reduced weight and size, and improved efficiency over an E-I laminate transformer in single phase linear power supplies. These benefits must be considered in relation to the disadvantages of slightly higher cost and greater inrush current. WHY CHOOSE A LINEAR POWER SUPPL...

The power transformer is a major apparatus in a power system; it is of great importance to detect incipient failures in power transformers as early as possible in order to minimize system outage. In this paper, the modified grey model was applied to predict the oil-dissolved gas trend of power transformers. Then, the future fault of power transformer can directly be identified by the trend anal...

Introduction. With the adoption of standards such as IEC555-2, there is a need to develop electronic ballasts for fluorescent lamps which can perform line current harmonic reduction and high input power factor correction (PFC). Among various filtering techniques, the active power factor corrector with a tioost converter has, been proven to be effective [l 31. The boost-type PFC circuit is one o...

Early detection of power transformer fault is important because it can reduce the maintenance cost of the transformer and it can ensure continuous electricity supply in power systems. Dissolved Gas Analysis (DGA) technique is commonly used to identify oil-filled power transformer fault type but utilisation of artificial intelligence method with optimisation methods has shown convincing results....

Reliable and continued performance of power Transformer is the key to profitable generation and transmission of electric power. Failure of a large power transformer not only results in the loss of very expensive equipment, but it can cause significant guarantied damage as well. Replacement of that transformer can take up to a year if the failure is not disastrous and can result in tremendous re...

High frequency models of large power transformers are required for analysis of transient interaction phenomena between transformers and the power system. Fast transient overvoltages may lead to transformer dielectric failures. Deeper understanding of the mechanisms may help to take actions against possible damages. This paper describes the simulation principle of transient interaction in matter...

This paper develops a novel dynamic correction method for the reliability assessment of large oil-immersed power transformers. First, with the transformer oil-paper insulation system (TOPIS) as the target of evaluation and the winding hot spot temperature (HST) as the core point, an HST-based static ageing failure model is built according to the Weibull distribution and Arrhenius reaction law, ...

A transformer is the most valuable and expensive property for power utility, thus ensuring its reliable operation is a major task for both operators and researchers. Online impulse frequency response analysis has proven to be a promising technique for detecting transformer internal winding mechanical deformation faults when a power transformer is in service. However, as so far, there is still n...

This paper describes interconnection between technical and economical making decision. The reason of this dealing could be different: poor technical condition, change of substation (electrical network) regime, power transformer owner budget deficit and increasing of tariff on electricity. Establishing of recommended practice as well as to give general advice and guidance in economical sector, t...