The Study Of Lightning Protection Performance For UHV Parallel-Two-Circuit-Transmission-Lines

In the 21 st century, all these years, due to the rapid economic development which makes some of our developed areas growing demand for electricity load, making our nation’s energy division with extremely unbalanced power load in these areas.In this extremely unbalanced supply and demand backdrop prompted the rapid development of China’s power industry, in order to improve the power supply in the process of supplying electric power to the load in the use of higher voltage level and a greater capacity to carry out more long-distance UHV transmission.But from some actual transmission line running survey results domestic and abroad, the probability of more high voltage overhead lines by lightning trip will be. So, how to design a lightning UHV transmission lines become a serious problem.Thesis research for our country 1000 kV UHV lightning performance Double Circuit AC transmission lines.Thesis for 1000 kV UHV Double- Circuit AC Transmission Lines features ATP-EMTP using electromagnetic transient simulation software to establish a simulation model of lightning counterattack.In modeling the counterattack when we fully comprehensive model takes into account the structural features typical tower UHV AC transmission lines, and also chose a different location in the tower at different times depending on the velocity of the impedance model;When the lightning current surge grounding resistance line, when presented characteristic is nonlinear;When the lightning current transmission line to the top of the tower will be the impact of the time, it will make the transmission line frequency voltage frequency voltage waveform generated random;Papers identified 1000 kV UHV Double- Circuit AC Transmission Lines LIGHTNING level approach is to use statistical probability method.The paper also analyzes the different factors 1000 kV UHV case with pole LIGHTNING double circuit AC transmission line characteristics.In the case of these different factors on the transmission line to counter resistance among the most sensitive parts of the Tower mine performance impact resistance;Wherein the double-circuit transmission lines than the reverse sequence of circumstances LIGHTNING performance when phase sequence is arranged to be higher;Negligible impact on the overall size of the distance between the transmission line LIGHTNING performance gauge file; another can affect the performance of the line as well as mine-resistant frequency voltage.Trip around the strike rate when the paper calculated transmission line in the final analysis by the use of EGM is after the introduction of the striking distance parameter k and improved ground inclination θ obtained;At the same time also it has introduced a mine-width and amplitude hit by the lightning current with some of the views from the association, but also for the procedures Farley width results EXCESSIVE subject was amended.Shielding Failure Rate Calculation results show that the final analysis of the line: the whole observation, along strike from growing line equivalent width coefficient A by mine will gradually decrease, its size will be as the ground of inclination θ increases become more apparent; striking distance coefficient k on a trip around the strike rate is variable k value as big trip around the hit rate decreases.