This paper presents an alternative approach using the differential logic associated to Artificial Neural Networks (ANNs) in order to distinguish between inrush currents and internal faults in the protection of power transformers. The Alternative Transients Program (ATP) has been chosen as the computational tool to simulate a power transformer under fault and energization situations. The Radius ...

Many industrial and commercial sensitive loads are subject to the voltage sags and interruptions. The static transfer switch (STS) based on the thyristors is applied to improve the power quality and reliability. However, the transfer will result in severe inrush current in the load transformer, because of the DC component in the magnetic flux generated in the transfer process. The inrush curren...

Transformer differential protection may be of malfunction at the emergence of inrush current, and it will affect the normal operation of the transformer. So the paper puts forward a new application of wavelet energy spectrum entropy-neural network theory in transformer microcomputer protection, in which the multi-resolution analysis of wavelet transform and information entropy technology are co...

In this paper we propose transformer-based solutions to several power quality problems. Elsewhere we have shown how to solve the acoustical noise emission problems. In this paper we introduce toroidal transformers with reduced inrush currents, transformers with reduced electromagnetic emissions, and other transformers useful to reduce the transfer of harmonics. With the low-inrush transformers ...

Transformer inrush currents are highmagnitude, harmonic-rich currents generated when transformer cores are driven into saturation during energization. These currents have undesirable effects, including potential damage or loss-of-life to the transformer, protective relay misoperation, and reduced power quality on the system. Controlled transformer switching can potentially eliminate these trans...

Paper analyzes a sparking phenomena that were observed on power transformers during their first few energizing. Sparks occurred the flange between tank cover and side, in spite of fact jumper (copper link) was used. The phenomenon from different manufacturers, with various transformer ratings, three or five limb core. proposes simple electromagnetic model for analyzing phenomena. Three-phase is...

This paper presents the use of Artificial Neural Networks (ANN) as a pattern classifier for the combined differential protection of generator-transformer unit with an aim to build a backup protection system to improve the overall reliability of the system. The proposed neural network model is trained and tested with an efficient Resilient Back propagation (RPROP) algorithm and Genetic Algorithm...

This paper presents an efficient wavelet and neural network (WNN) based algorithm for distinguishing magnetizing inrush currents from internal fault currents in three phase power transformers. The wavelet transform is applied first to decompose the current signals of the power transformer into a series of detailed wavelet components. The values of the detailed coefficients obtained can accurate...

In this work, a new approach applied to digital differential protection relay for a large power transformer is presented. First, the Fourier sine and cosine coefficients required for fundamental, second, third and fifth harmonic extraction have been determined using rectangular transfer technique. Then, these harmonics have been used in harmonics restrain and blocking techniques applied to diff...

In this paper, a differential protection schemes using fuzzy inference system (FIS) for power transformer protection is presented. First we review the concept of differential protection, and illustrate the magnetizing inrush current as they belong to the causes of the protection maloperation. Then relay logic and the algorithm that uses Discreet Fourier transformer for extraction of fundamental...