The paper presents the research results on electrostatic charging tendency (ECT) of transformer oil in a spinning disk system. The measurements were performed at different aging severity. Changes in static electrificationwere related to some classical aging indexes (conductivity, dissipation factor, water content, resistivity, etc.). Fast, inexpensive and reliable laboratory testing procedures ...

The most important parameter in transformers life expectancy is the hot-spot temperature level which accelerates the rate of aging of the insulation. The aim of this paper is to present thermal models for transformers loaded at prefabricated MV/LV transformer substations and outdoor situations. The hot-spot temperature of transformers is studied using their top-oil temperature rise models. The ...

To My lovely wife, Tong Wang And my to-be-born baby girl, Lucia Wang i ABSTRACT This dissertation is a systematic study of artificial intelligence (AI) applications for the diagnosis of power transformer incipient fault. The AI techniques include artificial neural networks (ANN, or briefly neural networks-NN), expert systems, fuzzy systems and multivariate regression. The fault diagnosis is bas...

Vibration signal analysis method is one of effective methods to monitor the condition of transformer windings and core. In this paper, the multi-channels vibration measurement system is set up and the vibration signals on the oil-tank surface of running transformer in the field are measured. The influences of transformer type and sensor positions on the measured vibration signals are analyzed. ...

It has been reported that breakdown voltage is affected by several factors, such as moisture, particles, acidity, and pressure [3,4,5,6]. The objective of this study is to investigate the dependency of the breakdown voltage on moisture using a representative set of oil samples and to point out the advantages of online moisture measurement. The Effect of Moisture on the Breakdown Voltage of Tran...

This paper describes an accelerated ageing experiment of transformer oil/paper insulation with preset moisture levels. These samples were tested with return voltage and polarisation/depolarisation measurements. Molecular weight has also been measured with Gel Permeation Chromatography (GPC). Results suggested the impact of moisture on the ageing of oil/paper insulation. An attempt has been made...

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...

he presence of moisture in a transformer deteriorates transformer insulation by decreasing both the electrical and mechanical strength. In general, the mechanical life of the insulation is reduced by half for each doubling in water content [l]; the rate of thermal deterioration of the paper is proportional to its water content [2]. Electrical discharges can occur in a high voltage region due to...

Dissolved gas analysis (DGA) of transformer oil is one of the most effective power transformer condition monitoring tools. There are many interpretation techniques for DGA results however all current techniques rely on personnel experience more than analytical formulation. As a result, the current techniques do not necessarily lead to the same conclusion for the same oil sample. A significant n...

Contamination of soil by polycyclic aromatic hydrocarbons is frequently associated with non-aqueous-phase liquids. Measurement of the catabolic potential of a soil or determination of the biodegradable fraction of a contaminant can be done using a slurried soil respirometric system. This work assessed the impact of increasing the concentration of transformer oil and soil:water ratio on the micr...