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The currently high energy efficiency demands and control requirements impose an extensive usage of power electronic devices and circuits in both domestic and industrial applications. These intrinsic nonlinear loads generate prominent level distortion of the electric current waveforms, which lead to additional losses and thermal stress within the power supply distribution system. Thus, due to the supplementary...
Although the transfer function (TF) method is widely used to detect deformation and displacement of power transformer windings, the sensitivity to minor defects is affected by several factors. This paper presents the influence of temperature on the TF of transformer windings. Nanosecond pulse was used to extending the frequency band of the measurement system. The experiment was carried on a purpose-made...
This paper provides the information on the diagnostics techniques for condition monitoring of power transformer (PT). This paper deals with the practical importance of the transformer diagnostic in the Electrical Engineering field. A review has been made on the modern development of this practical technology.
Transformer is the most important and critical equipment in Transmission Line Grid. Maintaining power system reliability can be done by maintaining transformer in its normal ageing. Transformers are designed according to its operation environment. As the result of global warming, maximum hotspot winding temperature of the transformer will exceed its normal ageing limit. Thermal monitoring is one of...
Power transformers represent the largest portion of capital investment in transmission and distribution substations. In addition, power transformer outages have a considerable economic impact on the operation of an electrical network. One of the most important parameters governing a transformerpsilas life expectancy is the hot-spot temperature (HST) value. The classical approach has been to consider...
A multipoint fiber-optic temperature sensor network integrated inside a power transformer for continuous monitoring of hot-spots on windings, cellulose insulations, and oil, is demonstrated and tested. The temperature sensors are based on proprietary encapsulated fiber Bragg grating (FBG) sensors and the optical interrogation unit uses a special designed narrowband high power broadband fiber source...
This paper presents a new method for calculating winding temperature gradient in large power transformers. A general formulation of the problem is made using the electrical analogy. An expression for the thermal resistance of the solid insulation is found using analytical methods. Expressions for the thermal resistance of the oil boundary layer for natural and directed oil flow are then found by correlation...
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