The detection of failures within power transformers is considered an important issue since these components are critical importance for system reliability; moreover, their replacement cost extremely high. In monitoring the transformer condition along its useful life, frequency-response analysis (FRA) has gained great interest due to sensitivity in windings and iron core. These can be detected by evaluating transfer function changes means statistical mathematical indices classified according...

Dynamic rating monitoring is a solution to face challenges in both the operation and planning of power systems. With thermal monitoring, dynamic overloads transformers are allowed; however, model used predict hot-spot must be capable ensuring assessment insulation life expectancy. Hence, this paper presents an online algorithm estimate transformers' order assess overload capability during short long times. The factors computed using estimations top-oil temperature. main characteristic...

The traditional methodology for defining the ampacity of overhead lines is based on conservative criteria regarding operating conditions line, leading to so-called static line rating. Although this procedure has been considered satisfactory decades, it nowadays sensible account more realistic when calculating its dynamic ampacity. Dynamic rating a technology used improve transmission assumption that not value but function weather and line's conditions. In order apply technology, necessary...

Sweep frequency-response analysis (SFRA) is a powerful technique to detect mechanical damage in transformer windings, such as deformations and displacements, well other failures, helping prevent severe damage. Since SFRA sensitive diagnostic technique, there are these days several commercially available measurement instruments perform the tests, but failure interpretation usually based on expert opinion. One of most advisable ways face task test results use mathematical indices abnormalities...

A new power transformer model for the accurate predetermination of transient resonant processes is introduced in this paper. The representation losses most important feature since it has been developed determination maximal stresses during resonance phenomena within transformers. equivalent circuit only contains constant lumped parameters. It represents very accurately frequency variation all impedances (real and imaginary parts) transformer, including mutual magnetic coupling. This allows...

A novel mesh-free axisymmetric methodology for the determination of low-frequency current distribution in foil windings is presented this paper. The proposed applies equivalent models winding and iron core, which are based on field produced by elementary geometric configurations boundary conditions derived from Maxwell's equations. Power losses due to skin effect proximity calculated with method finite-element (FEM). comparison both results showed excellent agreement. computational...

A deep analysis of the behavior transformer winding impedances for high frequencies is performed. The properties inductance matrices are analyzed, as well possibility making assumptions and their range validity. resistance also which has not been made in past. discussion on influence iron core undertaken. based impedance measurements carried out experimental windings. Finally, recommendations about most suitable models modeling transformers during transient resonance calculations.

In this paper a comparison between two methods for the calculation of hot spot temperature power transformer is presented. The first method proposed by C57.91 IEEE Standard which based on daily averages and exponential equations; other hand, second in differential equations hourly measurements. To compare these methods, ageing currently operating has been estimated. A results degradation using actual values hypothetical overload were performed. brief description each method, aging results,...

This article reviews direct and indirect methods developed for dynamic line rating on overhead lines, their applications (reduction of bottlenecks, congestion costs, load shedding, among others) in the operation control power systems as smart grid technology. Besides, four elements computation monitoring are identified, these are: sensors, communications, management information system analysis tools, which part integral systems. Finally, benefits challenges using phasor measurement units...

In this paper, a deep analysis of the behavior transformer winding impedances for high frequencies is performed. The properties inductance matrices are analyzed, as well possibility making assumptions and their range validity. resistance also which has not been made in past. discussion on influence iron core undertaken. based impedance measurements carried out experimental windings. Finally, recommendations about most suitable models modeling transformers during transient resonance calculations.

The sweep frequency response analysis (SFRA) is an technique for detecting winding displacement and deformation (among other mechanical electrical failures) in power distribution transformers. SFRA as a diagnostic must integrate both off-line measurements interpretation of the data order to provide assessment condition windings. record presently done by experts topic, whose criteria could not coincide. Although, there are some proposals making more objective, neither them human expertise...

The present document is a revision of the state-of-the-art problem life power transformer immersed in oil. difference between isolation and reviewed, loading guides IEEE IEC are analyzed and, that exists both to different values temperature shown.

Sweep Frequency Response Analysis (SFRA) has gained notorious popularity in recent years, due to its high sensitivity detect electrical failures or winding deformations transformers. Due several and good reproducibility, this technique is being widely studied, contributions the evaluation detection have been proposed, which use mathematical indicators for comparison of frequency response traces. The differences are normally evaluated using fixed ranges, leading results that not always...

A Power Transformer is an efficient and reliable machine that designed built to ensure a long useful life under normal operation. However, among the total number of operative power transformers installed in networks around world, there are many aged units, which approaching state final failure. This situation simultaneous aging becomes major problem, its proper solution critical for electric utilities because their financial performance economic viability unavoidably dependent on reliability...

Wound-core transformers are characterized by their economical and efficient design therefore widely used in power distribution systems; for this reason it is of paramount importance to determine electrical characteristics. One the most important parameters these leakage reactance, since what largely determines short-circuit currents voltage regulation. And yet authors have found a conspicuous gap scientific literature concerning analytical formulations calculation reactance wound-core...