The detection of furfural in transformer oil through surface enhanced Raman spectroscopy (SERS) is one of the most promising online monitoring techniques in the process of transformer aging. In this work, the Raman of individual furfural molecules and SERS of furfural-Mx (M = Ag, Au, Cu) complexes are investigated through density functional theory (DFT). In the Raman spectrum of individual furf...

This paper presents an algorithm based on a combination of Discrete Wavelet Transforms and neural networks for detection and classification of internal faults in a twowinding three-phase transformer. Fault conditions of the transformer are simulated using ATP/EMTP in order to obtain current signals. The training process for the neural network and fault diagnosis decision are implemented using t...

Paper presents electric and magnetic field computation of 35 kV voltage level of transformer substation 35/10 kV using CDEGS software. Based on well known theoretical considerations of electric and magnetic fields, a realistic simulation model of transformer station 35/10 kV was develop. All calculations are made for horizontal plane with height of 1,5 m above the soil changing coordinates alon...

Transformers are one of the more expensive pieces of equipment found in a distribution network. The transformer’s role has not changed over the last decades. With simple construction and at the same time mechanically robust, they offer long term service that on average can reach half a century. Today, with the ongoing trend to supply a growing number of non-linear loads along with the notion of...

In this paper a method for extracting Partial Discharge (PD) signals is introduced, which is implemented for evaluating electrical measured partial discharges on a 66 kV / 25 MVA fully interleaved winding of a power transformer. Applying wavelet transform to a signal produces a wavelet detail coefficient distribution throughout the time-scale, which depends on the mother wavelet chosen. This me...

Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations us...

DC bias will cause abnormal vibration of transformers. Aiming at such a problem, transformer vibration affected by DC bias has been studied combined with transformer core and winding vibration mechanism use multi-physical field simulation software COMSOL in this paper. Furthermore the coupling model of electromagnetic-structural force field has been established, and the variation pattern of inn...

In this paper, a novel computer based learning framework that bas been developed and applied for the on-line control and optimization of transformer core manufacturing process is presented. Tbe proposed framework aims at predicting core losses of wound core distribution transformers at the early stages of transformer construction. Moreover. it is used to improve the grouping process of the indi...

Transformer and feeder load balancing in a distribution system reduces the risk of overloads due to load changes. The possible out of service area following the occurrence of a fault is also reduced. However, keeping in view the life expectancy of the switches, it is desirable that the number of switching operations is kept to a minimum. A new algorithm for load balancing based on fuzzy set dec...