Power transformers represent the largest portion of capital investment in transmission and distribution substations. In addition, power transformer outages have a considerable economic impact on the operation of an electrical network. One of the most important parameters’ governing a transformer’s life expectancy is the hot-spot temperature value. Due to under estimation of stray losses in powe...

In many text books and papers such as [1]-[5], it is possible to find descriptions about shunt fault calculations and about the influence of the three-phase transformer connection Dyn on the fault currents distribution through distribution transformers. In [6] is described a method for digitally simulating a three-phase power system which is subjected to a fault at one location with blown fuse ...

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, ...

This paper establishes a link between Bayesian inference (learning) and predicate and state transformer operations from programming semantics and logic. Specifically, a very general definition of backward inference is given via first applying a predicate transformer and then conditioning. Analogously, forward inference involves first conditioning and then applying a state transformer. These def...

Reliable energy flow is paramount and power transformers are critical, and costly, assets in the grid. As an asset class, power transformers constitute one of the largest investments in a utility’s system. For this reason transformer condition assessment and management is a high priority. In several parts of the world the transformer fleet is operating beyond its design life and with higher ave...

This paper presents a design of a monolithic transformer using bond wires. The proposed transformer structure has several advantages such as high power handling and high efficiency. It shows that the measured insertion loss at the 1.9 GHz range is −1.54 dB (70%), which is higher than the spiral transformer of the same size. Also, it shows a phase error of less than 1 degree. key words: CMOS RF ...

New emerging mapping and ablation technologies are examined to improve acute success of ablations, while minimizing procedure time cost. Both ultra-low temperature cryoablation (ULTC) pulsed field (PFCA) ablations shown create durable transmural lesions using mapping-capable catheters similar design, except for size, number spacing electrodes. The accuracy efficiency left atrium (LA) with a nov...

in this paper are present the results of measurements of magnetic induction at some locationsin city bor (the east serbia) dating from the household electric devices and transformer stations suited near the residental areas. stress is on the extremely low frequent electromagnetic radiation from transformer stations and other high voltage instalations in urban areas. risk of the extremely low fr...