Effect Of Rising The Transmission Line Height On The Windage Yaw

Rising the height of the transmission line is a great significance of the optimization of transmission line,land saving,reducing the demolition,decreased the electromagnetic pollution and so on, but the requirement for the operation and maintenance of the transmission becomes higher. In the paper, the research emphasis is the influence to windage yaw when rising the height of the transmission line.Windage yaw fault of transmission line has been one of the important problems influencing the safe operation of power system. In recent years, the windage yaw flashover faults were occurred frequently in 110~500kV transmission lines. The most essential reason for the faults is the formidable natural conditions, which cause the clearance of the conductor/hardware-structure air gaps decreased. When the clearance cannot satisfy the requirement of lowest spark flashover voltage, the spark flashover is occurred.Based on collection and analysis about swing angle design documentation of transmission line in China, USA and Japan, a mathematical model of swing angle of conductor is developed in this paper, and some quantitative analyses of some parameters are also mainly discussed including wind pressure asymmetrical coefficient,wind pressure coefficient and wind height factor when rising the height of the transmission line; Through comparison of the election of some swing angle design parameter in and abroad; Discussion on the selection of the maximum design speed with rising transmission line; and effect of micro-terrain conditions on wind angle.A test is performed to study the effect of wind speed,wind direction on the discharge voltage. The test results indicate: when the wind direction along the discharge path, the discharge voltage of air gap is minimum and decreasing with the wind speed increasing; when the wind direction perpendicular to the of discharge path, the discharge voltage of air gap is maximum and increasing with the wind speed increasing.The wind speed of different height is collected by a measurement system. Through analyzing a large number of data, it is shown that the actual data is slightly larger than the theoretical one.Some prevention measures about flashover caused by windage yaw are put forward, which will optimize the design and make the faults caused by wind decrease largely.