The response of a cable can be used to analyze the variation of the material characteristics along its length. For diagnosis of possible ageing, it is necessary to know how cable design, material properties and cable insulation ageing affects the wave propagation. A cable model has therefore been worked out based upon the high frequency properties of the cable insulation and conductor systems. ...

Cellulosic paper and oil insulation in a transformer degrade at higher operating temperatures. Degradation is accelerated in the presence of oxygen and moisture. Power transformers being expensive items need to be carefully monitored throughout its operation. Well established time-based maintenance and conservative replacement planning is not feasible in a current market driven electricity indu...

pulse-width modulated (pwm) adjustable frequency drives (afds) are extensively used in industries for control of induction motors. it has led to significant advantages in terms of the performance, size, and efficiency but the output voltage waveform no longer remains sinusoidal. hence, overshoots, high rate of rise, harmonics and transients are observed in the voltage wave. they increase voltag...

• Transformers and capacitors • Other electrical equipment including voltage regulators, switches, reclosers, bushings, and electromagnets • Oil used in motors and hydraulic systems • Old electrical devices or appliances containing PCB capacitors • Fluorescent light ballasts • Cable insulation • Thermal insulation material including fiberglass, felt, foam, and cork • Adhesives and tapes • Oilba...

Influence of moisture on the instrument transformers’ paper-oil insulation and its further maintenance is described in this paper. Improved insulation drying method using vacuum and temperature regulation with definite regulation algorithm of parameters is proposed and analyzed by comparing it with conventional drying method.

Frequency Domain Spectroscopy (FDS) is widely used to estimate oil–paper insulation. The high moisture and long aging change the FDS characteristics of insulating oil–paper, so normalization processing required. Still, choice single activation energy needs further research. This paper studies characteristic insulation samples with different degrees improves traditional temperature correction me...

BACKGROUND Man-made vitreous fibres (MMVFs) are used in products for insulation and as reinforcement in materials. Contamination of the skin may arise through direct or indirect contact, and from the deposition of airborne fibres. The scientific basis regarding the effects on skin of MMVFs dates from 1970-1980. OBJECTIVES To investigate whether currently used insulation MMVF products still ca...

Ground heat is a renewable resource that is readily available for buildings in cool climates, but its relatively low temperature requires the use of a heat pump to extract it for heating. We developed a system that uses low temperature ground heat directly in a building wall to reduce transmission heat losses. The Active Low Exergy Geothermal Insulation Systems (ALEGIS) minimizes exergy demand ...

Improved detection of thermal insulation efficiency in buildings could substantially contribute to reductions in energy consumption and the carbon footprint of domestic heating systems. Thermal insulation standards are now contractual obligations at the construction stage, although they are not standardized in buildings that are already in operation: lighting, occupancy and temperature profiles...

Moisture is an important variable that must be kept under control to guarantee a safe operation of power transformers. Because of the hydrophilic character of cellulose, water mainly remains in the solid insulation, while just a few parts per million are dissolved in oil. The distribution of moisture between paper and oil is not static, but varies depending on the insulation temperature, and th...