Preventative diagnosis and maintenance of transformers has become more popular in recent times in order to improve the reliability of electric power systems. A number of transformers have recently been tested using Return Voltage (RV) and Dielectric Dissipation Factor (tanδ) measurements in the time and frequency domain, respectively. This paper outlines a circuit model which describes the diel...

Multidielectric polyethylene is a material that is generally employed as insulation for  the HVDC isolations. In this paper, the influence of temperature on space charge dynamics has been studied, low-density polyethylene (LDPE) and Fluorinated Ethylene Propylene (FEP) sandwiched between two electrodes were subjected to voltage application of 5kV (14.3 kV/mm) for extended duration of time ...

Moisture inside the footwear can considerably affect the thermal insulation. In this study with a thermal foot model there was simulated three sweat rates (3, 5 and 10 g/h). Five types of footwear with various insulation levels (dry insulation from 0.19 to 0.50 m2. K/W) were tested. The footwear insulation reduction was calculated for 1.5 hour period. The reduction in insulation was related to ...

Refurbishing existing buildings to reduce energy use is a priority worldwide greenhouse gas emissions. Millions of around the globe have old roofs that are poorly insulated, but with large roof surface areas could potentially provide significant renewable generation. Often, photovoltaic panels simply added onto regardless thermal integrity. However, due weathering, frequently need repairs over ...

Partial discharge (PD) inside cavities causes aging of a stator bar groundwall insulation system that can generates breakdown leading to equipment failures. One the conditions PD occurrence is electric field (EF) within cavity must exceed an inception mainly depends on size and pressure. A model has been simulated using Finite Element Method (FEM) in order study presence spherical insulation. S...

In this paper, the thermal performance of four common insulators in two internal and external insulation systems is investigated for the ASHRAE setpoint range by applying detailed numerical simulation and Anti-Insulation phenomenon. Anti-Insulation phenomenon and consequent extra load on the HVAC system can occur following the thermal insulation of a building if proper temperature setpoint is n...