in this study, the effect of wall orientation on the optimum insulation position in the wall from different perspectives is studied numerically. using crank- nicolson one dimensional transient heat conduction equation is solved for the wall with convection boundary conditions. outdoor temperature is considered as a periodic function of time. since natural night ventilation is used in the buildi...

The measurement of oil-paper insulation systems in the frequency domain provides novel diagnostic methods for quality control of materials and highvoltage power transformers. The first task is to measure and to analyse the dielectric behaviour of oil-paper insulation systems and their dependency on material quality, moisture content and ageing products in oil, paper and pressboard. Furthermore,...

INTRODUCTION In the prehospital care of a cold and wet person, early application of adequate insulation is of utmost importance to reduce cold stress, limit body core cooling, and prevent deterioration of the patient's condition. Most prehospital guidelines on protection against cold recommend the removal of wet clothing prior to insulation, and some also recommend the use of a waterproof vapor...

To identify the parameters of extended Debye model XLPE cables, and therefore evaluate insulation performance samples, sparsity-promoting dynamic mode decomposition (SPDMD) method was introduced, as well basics processes its application were explained. The amplitude vector based on polarization current first calculated. Based non-zero elements vector, number branches including coefficients time...

Equipment condition monitoring plays a crucial role in the overall integrity of the power system. As a result, utilities invest significant time and finances into equipment monitoring and maintenance in order to anticipate failures or accelerated aging in power equipment. Such monitoring includes regular insulation condition tests for switching devices, reactors, power transformers, generator w...

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. ...

polysulfide resins,with trade name of  g4 and g112, with short and long chain lengths respectively, were used as reactive modifiers to toughen epoxy resin. the effects of molecular weights of g4 and g112 on impact resistance, dielectric constant, thermal conductivity as well as decomposition  heat and adhesion properties of toughened epoxy were investigated. the impact strength and the dielectr...

This work is concerned with the hypothesis that lightning impulses can lead to accelerated ageing of extruded polymeric cables. The behaviour of an insulation material when suffering lightning impulses is different from that for DC or power frequency over-voltages. Shaped HDPE material samples have been manufactured using a mould tool. The samples then may be electrically aged using one of the ...

aging coefficient (ac) or aged-child ratio or age composition; takes into account the numbers and areas at both ends of the age distribution simultaneously. ac is the total number of individuals aged 65 years and more, divided by the total number of individuals aged 14 years, multiplied by 100. herein, age composition in iranian popu1ations, according to different provinces, place of residence ...