the infrastructure of the electricity grid and super grid system in the hitherto industrialized world was to a large extent built up in the decades following world war ii with a peak in investments around 1960-1980. this means that the flotilla of power transformers is now starting to reach projected lifetime of around 40 years. during the last couple of decades there has also been an ongoing d...

The infrastructure of the electricity grid and super grid system in the hitherto industrialized world was to a large extent built up in the decades following World War II with a peak in investments around 1960-1980. This means that the flotilla of power transformers is now starting to reach projected lifetime of around 40 years. During the last couple of decades there has also been an ongoin...

In order to evaluate the reliability of using repulped cellulose in transformers, the aging process was applied on standard and repulped cellulose in a laboratory accelerated model by increasing of temperature to 150 ° C and their behavior was monitored by measuring the amount of 2-furfural released in oil by HPLC (High Performance Liquid Chromatography) in the consecutive aging periods and...

Faults and damage in oil-filled power transformers has a devastating effect on the overall reliability of electrical power systems. Several factors, especially electrical and thermal stresses age the transformer and subject them to incipient faults. These faults, if left undetected will cause deterioration and eventually lead to failure of the transformer [1]. The presence of faults such as arc...

Electrical energy is the paramount need in a nation’s development. To cater for large demand for electricity there is a need for reliable and proficient power system. For a power system to work reliably, the role of Transformers is critical. Health of the transformer mainly depends on its insulation. Among the different insulating material used in transformers, mineral oil is the most widely us...

Power transformers are crucial in an electric power system. Failures in transformers can affect the quality and cause interruptions in the power supply. Partial discharges are a phenomenon that can cause failures in the transformers if not properly monitored. Typically, the monitoring requires high-cost corrective maintenance or even interruptions of the power system. Therefore, the development...

Dissolved gas analysis (DGA) is attracting greater and greater interest from researchers as a fault diagnostic tool for power transformers filled with vegetable insulating oils. This paper presents experimental results of dissolved gases in insulating oils under typical electrical and thermal faults in transformers. The tests covered three types of insulating oils, including two types of vegeta...

Oil-impregnated paper is widely used in power transmission equipment as a reliable insulation. However, copper sulphide deposition on oil-paper insulation can lead to insulation failures in power transformers. This paper presents the influences of copper sulfur corrosion and copper sulphide deposition on copper wires and oil-paper insulation in power transformers. Thermal aging tests of paper-w...