The principle of lightning arrester, classification as well as how to choose the basis knowledge of

by:Mings     2020-04-15
Define lightning arrester: used to protect electrical equipment from lightning when high transient overvoltage hazard, and limit the stream of time, often limit stream assignment of a kind of electrical appliances. Lightning arrester is sometimes referred to as over-voltage protector, overvoltage limiter. Scope of exchange non-clearane metal oxide arrester used to protect the insulation of the ac power transmission and transformation equipment, from lightning overvoltage and operating over-voltage damage. Suitable for transformer, transmission lines, distribution panel, switchgear, power metering box, vacuum switch, parallel compensation capacitor, a rotary motor, semiconductor overvoltage protection, etc. Characteristics and principle of exchange non-clearane metal oxide lightning arrester has excellent nonlinear voltage ˙ characteristics, good response characteristic and no big stream, flow capacity, low residual, ability to suppress overvoltage, filth resistance, anti-aging, altitude are not legally binding, simple structure, no clearance, seal tightly, long service life, etc. The lightning arrester under normal system operating voltage, the present state of high resistance, only through microamps level current. In overvoltage strong it appears low resistance, current limiting the arrester lightning arrester is divided into many kinds of residual pressure at the ends of the classification, a metal oxide surge arrester, line type metal oxide surge arrester, non-clearane metal oxide arrester line type, insulation composite coat of metal oxide surge arrester, detachable arrester. Arrester type tube type of surge arrester, valves are the main types of lightning arrester and zinc oxide lightning arrester and so on. The main working principle of each type arrester is different, but their work is the same, the substance is to protect the communication cable and communication equipment from damage. Lightning arrester connection between the cable and the earth, usually with the protection equipment in parallel. Lightning arrester can effectively protect communications equipment, once appear, abnormal voltage, lightning arrester will happen and protection. When the communication cables or operation of the equipment under normal working voltage, lightning arrester will not produce effect, for the ground as a break. Once appear, high voltage, and endanger the protected equipment insulation, lightning arrester action immediately, the high voltage surge current leads to the earth, and the limiting voltage amplitude, protection of communication cables and equipment insulation. When overvoltage disappear, lightning arrester rapid restorable, make the normal work of the communication line. , therefore, is the main purpose of lightning arrester through parallel nonlinear resistance, discharge gap or to cut picture of invasion of flow, reduce overvoltage protection device is by value, so as to protect the communication lines and equipment. Not only can be used for protection of lightning arrester of high voltage, high operating voltage can also be used to protection. Arrester is used to protect all kinds of electrical equipment in the power system from lightning arrester sort, operating over-voltage and power frequency voltage transient overvoltage impact a damaged by electrical appliances. Types of lightning arrester are mainly protect clearance, valve type arrester and zinc oxide lightning arrester. Protection gap is mainly used to limit over-voltage of the atmosphere, commonly used in power distribution system, line protection and substation into segments. Valve type lightning arrester with zinc oxide lightning arrester used for the protection of the substation and power plant, the system is mainly used for 500 kv and below, limit over-voltage of atmosphere in the ultra-high pressure system will be used to limit overvoltage and inner overvoltage backup protection. How should the arrester choose ( 1) The arrester the base first, and then bottom-up by lightning arrester sets each unit ( Section) 。 ( 2) Lightning arrester has been assembly test and qualified before they go out, on-site installation should strictly according to the manufacturer code assembly, are not interchangeable, lest make feature change. ( 3) Arrester with string and umc Yin, when installation should be matching, nonlinear coefficient between the phase composition unit close to each other, the difference should not be greater than zero. 04. ( 4) Lightning arrester contact surface should be wiped clean, remove the oxide film and paint, and painted a layer of electricity compound. ( 5) Lightning arrester should be installed vertically, sag deviation is not more than 2%, between the flange face pad metal when necessary correction. Three phase center should be on the same straight line, on the same side as the nameplate should be located in easy to observe, equalizing ring should be installed level, with be bored with child will finally aperture smoothing and coated with paint. ( 6) Tension insulator string, fastening, in phase of each string tension should be balanced, so as to avoid lightning arrester by additional strain. ( 7) Discharge counter should be good seal, reliable operation, three-phase installation position is consistent, convenient for observation. Reliable grounding, counter instructed return zero. ( 8) Zinc oxide lightning arrester exhaust channel should be unobstructed, when installation should avoid the discharge gas, flashover and cause short circuit or over the ground, and shall not be spray and other equipment. Lightning arrester cleaning, inspection and the measurement of insulation resistance dangerous points and control measures
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