HVDC (high voltage direct current) transmission is an effective way to transport electrical power over long distances by using direct current. The insulation system of HVDC components has to be designed for both AC and DC field distributions. It consists of mineral oil and pressboard. The used insulation material behavior has not been completely understood under DC stress. In this paper, electr...

The conductivity mismatch in the composite insulation of high voltage direct current (HVDC) cable accessories causes electric field distribution distortion and even insulation breakdown. Therefore, a liquid silicone rubber (LSR) filled with SiC nanoparticles is prepared for the insulation of cable accessories. The micro-morphology of the SiC/LSR nanocomposites is observed by scanning electron m...

The condition of the internal cellulosic paper and oil insulation are of concern for the performance of power transformers. Over the years, a number of methods have been developed to diagnose and monitor the degradation/aging of the transformer internal insulation system. Some of this degradation/aging can be assessed from electrical responses. Currently there are a variety of electrical-based ...

ii Τὸ εὖ γίνεσθαι μὲν παρὰ μικρόν, οὐ μὴν μικρὸν εἶναι. Abstract The world's first commercial High Voltage Direct Current (HVDC) transmission link was built in 1954 between the Swedish mainland and the island of Gotland. At that time, it was proved that HVDC transmission is technically feasible. Since then, HVDC cable systems have been used worldwide in electrical energy transportation. Most HV...

Dielectric breakdown of solid insulation has been studied for many years but the mechanisms that cause breakdown have not been fully understood. Charge injection always occurs at high electric fields and especially under dc conditions. The presence of space charge in solid dielectrics will result in distortion of electric field distribution. Dielectric breakdown can be initiated in the region w...

Twenty new cells have been purchased, in conformity to recent action of the State Board, as an addition to the storage battery plant of this department. The cells have a capacity of forty ampere-hours. T h e r e are now available for direct current work, voltages of 40, 72, n o and 500 volts respectively. This will largely increase the range of experimental work which can be done by electrical ...

A phenomenon that is typical in dc insulation is the accumulation of space charge which can significantly enhance the local electric field. This phenomenon is of special importance for polymeric insulation. Accumulation of space charge proved to be a limiting factor for HVDC applications. The goal of this paper is to show the different behavior of epoxy nanocomposites under various dc field str...

The principle of partial discharge detection is that through partial bridged discharge under high voltage electric field, it detects the inner air-filled cavity of high-voltage insulators. And it is a nondestructive detection method based on discharge magnitude to judge the insulation quality. The detecting system that adopts the partial discharge detection is more rigorous than testing system ...

The doping effect of graphene nanoplatelets (GNPs) on electrical insulation properties of polyethylene (PE) was studied by combining experimental and theoretical methods. The electric conduction properties and trap characteristics were tested for pure PE and PE/GNPs composites by using a direct measurement method and a thermal stimulated current (TSC) method. It was found that doping smaller GN...