Power transformers are protected by different relays that operate independently. Malfunction of each relay has a major role in reducing the reliability of the protection system. In order to mitigate the main drawbacks of the power transformer relays, an overall protection scheme is presented in this paper. This scheme proposes a novel multi criterion algorithm using decision-making based on fuz...

Power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. Once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. The resonant overvoltages may destroy the insulation between turns and cause to insul...

Energizing of large power transformers is considered a critical event in the operation of an electric power system. When a transformer is energized by the grid or utility, it takes very high value current known as inrush current, the typical value of this current could be ten times. This inrush causes many problems like mechanical stress on transformer & harmonics injection to generator winding...

Power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. Once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. The resonant overvoltages may destroy the insulation between turns and cause to insul...

Traditionally, the protection of power transformers has been relegated to the application of transformer differential and backup overcurrent relays to provide shortcircuit protection. With the advent of modern multifunction transformer packages, differential and overcurrent protection are only two of many protective and logic functions that can be incorporated into the transformer protection pa...

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...

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 ...