frequency response analysis (fra) is popular technique which has been used since the last decade as a diagnostic method for transformers. however, accurate interpretation of fra measurements is still challenging. recent studies reveal that apart from winding deformation, fra data can also be influenced by moisture variation in transformer paper insulation. hence, a specific transformer’s model ...

Transformer liquid dielectrics evolved where mineral oil has been the dominant choice until emergence of synthetic esters and natural esters. Natural ester-based oils have under extensive investigations to enhance their properties for replacing petroleum-based oil, which is non-biodegradable poor dielectric properties. This paper focuses on exposition ester application in mixed transformer diel...

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...

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...

Power transformers in service are subjected to a wide variety of electrical, mechanical and thermal stresses capable of producing insulation faults. This type of failure figures amongst the most costly faults in distribution networks since it produces both machine outage and electrical supply interruption. Major research effort has therefore focused on the early detection of faults in the insul...