About 30 percent of all overhead power distribution outages are caused by failing electrical equipment. Arc and partial-arc sources predict an eventual outage. Replacing failing equipment reduces all reliability index figures. The novel sensing device discussed accurately determines the Global Positioning System (GPS) location of an arc source from moving vehicles. It can be called an outage-avoidance system.
The transmission capacity of overhead transmission lines is limited largely by its operation temperature, which is determined by the competition between the heat generation by load current and the heat dissipation into the environment. The ohmic heat generation is a function of the conductor resistivity, which is a function of its temperature and current distribution inside the conductor, taking the skin effect into account. The heat dissipation is influenced by the temperature of the conductor and the air, the surface condition of the conductor, the wind, the sunshine, and the humidity of air, etc. Finite Element Analyses are carried out in this paper to calculate the thermal dynamics by coupling the thermal field and the fluid mechanical models. The results show the temperature distribution and the evolution history in the conductor - air system under various environment conditions. Thus the maximal load level can be defined accordingly. The calculation also gives the time required for the conductor to reach equilibrium with load and environment changing. This information can help the grid operators to decide how to dispatch the loads among multiple transmission lines, either as a temporary routing or as a steady state solution.
Material's micromechanism determines its property, therefore we should research on polymer material's micromechanism so as to further explain its insulation characteristic. From material's infrared spectrum, main function groups can be found through the wave numbers of absorption peaks. In the experiment five kinds of polymer materials, which are kraft paper, PC, PET, PTFE and PPS, are aged in the condition of high temperature and high electric intensity. Polymer materials before aging and under aging for one to three months are tested for infrared spectra. The absorption peaks of polymer materials' infrared spectra respectively reflect their main function groups. From the comparison of infrared spectra of the polymer materials before and after aging, we can find transformation of characteristic function groups of the polymer materials under aging. In this paper the infrared spectral characteristics of mineral oil impregnated polymer materials under electro-thermal aging are preliminarily analyzed.
The electric performance of the one kind of hydrogenated transformer oil and three kinds of naphthenic transformer oil had been tested by using the experimental methods specified in the GB/T7595-2008. A series of experiments, including dielectric dissipation factor, volume resistivity, dielectric constant, breakdown voltage and electrostatic charging tendency, mechanical impurities, corrosive sulfur and sulfur content had been conducted. Compared with the other three naphthenic transformer oil, the hydrogenated transformer oil performed the best electrical properties.
