This paper investigates protection integrity of distribution transformers in Ghana. The purpose of the study was to find the main causes of distribution transformer failures in Ghana. The study was conducted in the Ashanti East Region, one of the operational areas of Electricity Company of Ghana ECG with high incidence of distribution transformer burnouts. Data on status of protection systems o...

Energization of a transformer results in sudden flow of current which is an effect of core magnetization. This current will be dominated by the presence of second harmonic, which in turn is used to segregate fault and inrush current, thus guaranteeing proper operation of the relay. This additional security in the relay sometimes obstructs or delays differential protection in a specific scenario...

Power transformers are among the most important and expensive equipments in the electric power systems. Consequently the transformer protection is an essential part of the system protection. This paper presents a new method for locating transformer winding faults such as turn-to-turn, turn-to-core, turn-totransformer body, turn-to-earth, and high voltage winding to low voltage winding. In this ...

In this paper a overcurrent protection using concept of symmetrical component for power transformer is presented .first we review the concept of symmetrical component. Secondly we investigate how the concept of symmetrical component can be used to improve the transformer protection scheme and how it helps to discriminate the fault and non fault events. For this an algorithm and discrimination c...

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...

Three-phase synchronous motors are widely used in the industrial motor driven systems. Variable frequency drives (VFDs) which allow soft-start of motors produce PWM voltage. Numerical relays are used in the protection schemes of these high voltage motors. The location of current transformer (CT) is an important criterion in the protection circuit. Impact of harmonics and the location of current...

This paper proposed a new wavelet based method to identify inrush currents and to distinguish it from power system faults. The proposed algorithm extracts fault and inrush generated transient signals using DWT. Transient current signals at both sides of a transformer are firstly captured. The wavelet transform is a relatively new and powerful tool in the analysis of power transformer transient ...

This paper presents a novel power transformer differential protection scheme by using combined Wavelet Transform and Artificial Neural Network which provide the means to enhance the classical protection principles and facilitate faster, more secure and dependable differential protection for power transformer. Wavelet transform is used to extract the feature from transient signal and the neural ...

internal turn-turn faults (ttf) are the most common failures in power transformers, which could seriously reduce their life expectancy. although common protection schemes such as current-baseddifferential protection are able to detect some of the internal faults, some other minor ones (such as ttfs andshort circuit near the neutral point) cannot be detected by such schemes. likewise, these rela...

For several decades, the power system protection relay has experienced many important changes, from purely electromechanical type to the mixture of electronic and electromechanical type, then to fully static, and now fully numerical relays based on microprocessors. In the transformer protection area, similar changes can be seen. It is a dream for protection engineers to have a system that not o...