避雷针原理解析英文.doc

Text: the. Preface: early in 1749 years, American franklin, based on cutting-edge emits no vision to neutralize the charge LeiYun charge, can avoid the idea of lightning, invented the lightning rod. But after the lightning and the lightning installation, no itself not only more vulnerable to avoid thunder lightning. According to this phenomenon, the Soviet union in 1753 years SuoFu receive forward lightning rod is crooked lead thunder substation games in itself, make its surrounding objects from lightning, namely actually lead thunder lightning itself needle explanation. LeiLan again in 1755 klingons, publish articles concerning lead thunder lightning itself has both the dual role of corona, have, but in different conditions, or show lead thunder, lightning strikes or presentation role role. This is done in a more objective lightning, comprehensive explanation. Unfortunately many people to notice of lightning rod of franklin 1755 role explanation. Two hundred years, direct lightning protection area in the lightning though a wide range of applications, but because of the complexity of lightning process, the lightning rod role is also not identical, know that now application lightning rod head shape according to the varied, have the concept of franklin in 1749, based on the tip LeiYun charge and discharge, avoid lightning, and use biforked many pointed needle. More common in buildings and structures on lightning rod. There SuoFu 1753 years according to receive, the concept of LeiYun and the earth is to turn the lightning lead thunder electric field, in itself, avoid surrounding equipment be struck by lightning, and use single flat metal pipe or great. In the power system hair, substation lightning rod. Some also think that lightning rod head actual size larger or smaller relative to the earth or LeiYun is pointed tips, so head make it small spherical also lightning does not affect its lead thunder role, see more at metal flagpole with metal pipe type ball lightning rod. And all kinds of lightning rod head what different lead thunder effect rarely research. In some authoritative magazine, the lightning rod head shape often shown as shown in figure 1 of furcated. This creates furcated lightning rod head lightning protection effect seems more Good concept, and even appeared ray harm accident, a also blames lightning rod head without bifurcate, think in ray needles on lightning protection of bifurcation only more reliable, asks to install bifurcate lightning rod head. For example, a force of ammunition combing-out lightning protection device is installed, the original design of the steel tube of lightning rod, crew-cut but troop rotation, new head forward without biforked lightning troops, and the copper to think lightning protection effect is not reliable and refused to sign the hand to receive. This makes some local specialized production, sales, non-ferrous metal fork head type lightning rod. In order to validate all kinds of lightning rod head of lightning effect, we all shapes of lightning rod head compared the simulation test. Second, various shapes lightning rod head simulating test lead thunder Lightning discharge is punctured air gap for decades to hundreds of meters, according to lightning optical, but also the photo analysis can be divided into three stages, namely guide discharge stage, after ZhuFang electric stage and light discharge stage and problems with direct lightning protection after discharge stage light is irrelevant. The direct lightning protection mainly depends on the issues lead thunder forerunner discharge stage (overvoltage protection problems depends mainly on ZhuFang electric stage). So as long as analog pilot discharge stage, length is in 1 meter or more long air discharge gap in essence, and has the same properties lightning discharge. In time due to lightning discharge not controllable and site for the study of the effect of the lead thunder lightning law and discharge gap only through long simulated experiments to. Trials with 2 x 2 LeiYun to simulate the flat, with a 1200KV by protecting resistance dc voltage generator connection, and LeiYun for control starting isoelectric point, in the center of LeiYun electrode install a 20cm long metal bar, used to simulate LeiYun pilot. To the distance of electrodes 1.1 m. Lightning rod model made use wire, high 88 . The schematic diagram as shown in figure 1. Lightning rod needles shape respectively (1) the needle, and ground it very sharp pointed needle as; (2) the lightning rod, the top ground flat as plain; (3) in the lightning rod welding a 1.55 mm on top of the ball, the abbreviation ball needle; A pointed except the central better-even from tip down the lightning rod, the whole high in model, each other poor in 3.75% 120 , elevation For 45 , welding three inclined radiate upward, long for model of all high 3.75% corona needles, abbreviation fork needle tip. We have developed using optical fibre dc high voltage meter LeiYun field to simulate the dc high voltage electric fields Strength of different shape measurement on the lightning rod electric field intensity probe measurement results such as table 1, measurement of the bar Thing is, in LeiYun lead directly into different shapes respectively the lightning rod, measuring instruments in the probe Lightning rod twice the lightning rod just above the position, high electric discharge pointed needle to an external voltage as 100%. When an external voltage must tip needle and fork probe in dc high voltage electric field in the electric field intensity vertical distribution curve as shown in figure 2. The simulation Y - E (that) curve: near field of electric intensity, near the lightning than fork pointed needle, needle much higher in leading LeiYun height, fork near field of the needle needle inverse ratio, pointed, whether pointed needle or high needle E dy fork U, U to simulate = LeiYun electrode for a dc voltage. This and electrician foundation theory is that with the measurement result is credible. Three, the conclusion Now put into use of various shapes lightning rod head all change electric field, lead thunder from their own role. But their lead thunder results are very different, bifurcate type lightning rod head wasted non-ferrous metal and increased processing fees, although many investment by lightning rod which the bifurcation in engineering of manpower and material resources of proportion of small, but bifurcate type corona The needle, it is worst lead thunder effect, but no harm accident to spend more money to buy ray is obviously not worthwhile. Unfortunately there are still many people have no knowledge. Through experimental research, we simulated the conclusion is the root of the head of a singl