| In recent years, with the rapid development of China's electric power industry,transmission line voltage levels are continuously improving. As significant parts of the power system, overhead transmission lines and substations are often affected by various natural disasters. Lightning disaster is a typical natural climate disaster, and lightning over-voltage is one of the main causes of transmission line trip accidents. Therefore, for the safety and stable operation of power grids, it is necessary to combine with the grid characteristics of Fuxin, in order to carry out lightning risk assessment techniques research on substation lightning over voltage and lightning protection of transmission line.Firstly, combined with the development process and research status of the transmission line lightning protection technology, the lightning formation and development mechanism were illustrated. Internal discharge of lightning, thunder and lightning discharge and lightning on earth discharge process, with the thunderstorm and thunderstorm hour, ground lightning density and transmission line lightning density were introduced in detail.Secondly, equivalent models of electric equipment which are applied in the simulation were proposed, mainly including lightning model and equivalent circuit, the amplitude of lightning current, lightning current waveform is computed, tower of multi wave impedance model, lightning arrester model and transformer equivalent model.Based on a 500 kV substation in Fuxin power network, simulation analysis of the overvoltage was completed. The results show that the voltage of the transformer, the outlet bushing and the current transformer far exceeds the basic impulse insulation level,thus the importance of lightning protection work is demonstrated.Thirdly, transmission line integrated lightning protection assessment and treatment technology was studied. Measures were taken such as decreasing the angle of ground protection, increasing line insulating ability, selecting reasonable tower ground resistance,setting up earth coupling, installing line arrester, lightning line erection, installing automatic reclosing device, neutral non effective grounding and lightning protectionwork to strengthen the management to carry out comprehensive lightning protection work. The development of transmission line lightning protection scheme and technical economic evaluation index were determined.Finally, the lightning protection technology of 220 kV Shuihei 1/2 line and Jindong1/2 transmission line is carried out, and the causes of lightning trip accident are summarized. After the transformation of the line in the lightning severe weather are no lightning accident that take protective measures to avoid transmission line lightning disaster and reduce the lightning caused by grid and equipment fault, ensuring the power grid safe and reliable operation. |
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