Fault analysis and modified measures of 500 kV compact transmission line

During the period of February 27 to March 4, 2007, a rare snow storm hit North China and caused many 500 kV compact transmission lines to trip and fault. In order to improve the power transmission line's ability to withstand natural disasters, it is necessary to study the dynamic characteristics of 500 kV compact transmission line under a variety of external force in adverse environments. We studied the dynamic characteristics of 500 kV compact transmission line under heavy wind load. A numerical simulation method was adopted to study the dynamic characteristics of 500 kV transmission line in adverse weather conditions especially under great wind load. The most economical and reasonable measures in the dangerous condition arisen in the simulation were put forward to improve the safety of the 500 kV compact transmission line. For 500 kV compact transmission line with inverted V type wire and under 32 m/s wind loads impact, when the conductor spans is more than 800 m, a phase-to-phase spacer should be installed on the middle of the horizontal phases; when the conductor spans is 300~600 m, the minimal phase-to-phase distance appears on the top-bottom phases but not the horizontal phases as generally believed.