Application of Special Arresters on 138 kV Lines of Application Power Company
Special zinc oxide series gapped line arresters were installed on Appalachian Power Company 138 kV lines having high tower footing resistance and severe lightning exposure. This effort was part of an experiment to explore means of reducing lightning flashovers in exposed locations where low ground resistances are not feasible. Because of possible future voltage uprating of these lines, the arresters were built in the form of high strength nonporcelain mechanical struts, designed to limit phase conductor swing. This paper describes the field installation of these experimental arresters and their instrumentation and reports operating experience in 1983.
Application Studies of Line Arresters in Partially Shielded 138 kV Transmission Lines
The application of arresters on transmission lines has been one of the most effective alternatives for the reduction of lightning flashover rates. This paper reviews previous methods for evaluating lightning performance of lines with arresters. Improved calculation of line outage rates are developed to include power freuency voltage and arrester failure rate evaluations, based on field experience. The transmission lines are modeled in full detail in the ATP program and the outage rates are calculated with Monte Carlo's method. Probability energy stresses on arresters are evaluated for strokes on conductors and shield wires as a function of tower footing resistance.
Simulation study of high power microwave generation by virtual cathode oscillation in coaxial vircator
Summary form only given, as follows. We have numerically simulated the high power microwave generation by virtual cathode oscillation in a coaxial vircator with 3 dimensional PIC code Magic. It is noted that the coaxial vircator has the advantage of an enhancement of power efficiency and gaining of narrow bandwidth frequency. The study is focused on the design of a diode structure for a coaxial vircator suitable for Chundoong IREB pulser (Max. 600 kV, 85 kA, 60 ns). It consists of a center annular cathode, a cylindrical meshed-anode and a reflector. The simulation results showed that the coaxial vircator can indeed be operated at the selected frequency with the narrow bandwidth and the microwave output power strongly depends on the position and geometry of the reflector. From this simulation results we expect that the maximum microwave output power will be obtained by the reflector of 4 cm in width and also 4 cm in distance away from the IREB, where the resonant frequency of microwave from coaxial vircator is simulated to be 6.577 GHz.