Research On Physical Simulation And Motion Characteristics Of Secondary Arcs Of Half-wavelength Transmission Lines

With continuous development of economy as well as growing demand of electicity, strategic conception of ultra-high-voltage(UHV) transmission was put forward by the State Grid corporation. The half-wavelength AC transmission(HWACT) is attracting more and more attention home and abroad owning to its unique economic and technological advantages, especially suitable for large-scale power transmission with long distance. Self-extinction of secondary arc is one of the key technical issues of HWACT technology, which is closely realted to the success of single-phase auto-reclosure. The principle research work focus on the physical simulation of secondary arcs of HWACT lines as well as its mathematical modeling. Investigations on the mechanical characteristics of secondary arcs were carried out to research its motion characteristics. The research achievements in this dissertation have further developed the fundamental theory and analyzing methodologies of HWACT lines, and present great significance for both scientific research and engineering applicition.Low voltage(LV) experimental platform for simulation of secondary arcs of HWACT lines with installment of high speed grounding switch(HSGS) was established. A large amount of experiments were carried out to explore the physical characteristics of seconday arcs. Through the measured waveform of arc current and arc voltage as well as recorded images, motion characteristics and arcing time of secondary arcs were researched with respect to the conventional short transmission lines. The relationship between secondary are and gradient of recovery voltage with arcing time of secondary arcs were presented. Both u-i characteristics of shorten arc and secondary arc and dynamic resistance of secondary arc were studied. The influence of wind on the motion characteristics and arcing time of secondary arc were analyzed in detail with valuable achievement. Chain arc model was employed to account for the the motion characteristics of secondary arcs. Taking into account electromagnetic force, wind load and thermal buoyancy, air resistance and so on, comprehensive force model of secondary arcs on HWACT lines was built as to research the influence of secondary current, wind direction, wind speed on the secondary arcs. The simulation results show a good agreement with the experimental measurement.