The Lightning-shielding Design Of A Transmission Line And The Research Of Lightening Location System In Shenzhen

Lightning is a natural phenomenon. The harm of lightning on power equipment, especially on a transmission line, is analyzed in this thesis. By the lightning-shielding design of a transmission line, some issues are investigated in detail. These issues include how to improve the lightning-shielding level of a transmission line, how to lower effectively the lightning trip-out rate of a transmission line, and how to decrease the impact of lightning on the safe operation of a power grid. At the same time, the design of the lightning location system in Shenzhen is developing. It would greatly shorten the time needed to locate points of troubles that were stricken by lightning, and reduce the losses associated with power blackouts caused by lightning strikes.Firstly, the principle of lightning discharge to a transmission lines is described in this thesis. The forming and developing processes of lightning are introduced. Also introduced are the forming and developing processes of lightning voltage and lightning current, as well as the discharge principle under the breakdown of an insulator. The main calculation methods of the lightning parameters, the lightning-resistance level, the lightning trip-out rate, the inducing lightning and the direct striking lightning are put forward. Secondly, several practical ways of lightning-shielding design of a transmission line in our country are analyzed. These ways include the reasonable choice of right-of-way of a transmission line, the rational design of lightning conductors, the lowering of tower's grounding resistance, the installation of lightning arresters, the installation of coupling lightning conductors, and the improving of line insulation level, and so forth. Some of them are analyzed in detail and studied quantitatively.It has become an urgent issue to establish a lightening location system so as to ensure the safety of the electricity network, given an increase of lightening strikes that have paralyzed elevated power cables in Shenzhen City. In this thesis, a design and development plan for a lightening location and analytical system is put forward. The plan is based on the directional location and GPS time-of-arrival location technique. The system would enable users to locate points of lightening strike in a timely, accurate and convenient manner, and to conduct search and analysis. It would also enhance the capabilities in preventing lightening strikes.