Ppt and seminar report on icing of power transmission line
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Ice formation of power transmission lines during winter storms is a persistent problem that causes disruption and costs millions of dollars in repair costs. High frequency excitation at about 8-200 kHz has been proposed as a method for melting ice. The method works by a combination of two mechanisms. At these frequencies, ice is a lossy dielectric, causing warming directly on the ice. In addition, the effect of the skin causes the current to flow only in a thin layer on the surface of the line, causing resistive losses and consequent heating. This article describes the design of systems to implement this method in lines up to 1000 km long. We also report experimental deicing tests of a 1 m simulated line using dielectric losses on ice using a prototype system that applies a power of 33 kV, 100 kHz.
A capacitive measurement principle to detect the formation and accumulation of ice in an overhead transmission line, for use with an autonomous monitoring system. The proposed scheme may use a linear or circular electrode geometry. Capacitances between electrodes are measured by a capacitance to digital converter for linear and circular type electrodes mounted on the conductor surface. Ice formation and ice sheet thickness can be determined by measuring the capacitances formed by the electrodes maintained at different distances, exploiting time signals and differences in air, ice and water permissiveness. A prototype system has been developed in the laboratory and the results of the tests along with results of finite element simulations are presented. The results of the tests show a good agreement with the finite element analysis and the developed system successfully detects the icing of a transmission line.