The importance of lightning protection for transmission lines

Lightning is a magnificent and somewhat intimidating electrical discharge accompanied by lightning and thunder. The condition of lightning is that there is accumulation and polarity in the thunderstorm cloud. Thunderbolts generally occur in cumulonimbus clouds with strong convection development, so they are often accompanied by strong gusts and storms, sometimes accompanied by hail and tornado, and often ice crystals in the upper part of the cloud. The freezing of ice crystals, the breaking of water droplets, and the convection of air create electric charges in the clouds. The distribution of charge in the cloud is complex, but generally speaking, the...

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The harmful form of lightning

Lightning invades buildings (structures), equipment, people, livestock, etc., which will cause disasters, mainly in the form of: Direct lightning strike (including direct lightning strike, around lightning strike) -- in the area of lightning activity, lightning directly through the human body, buildings (structures), equipment, and other electrical discharge to the ground generated by the phenomenon of the direct lightning strike. Indirect lightning strikes -- lightning currents invade buildings (structures) in the form of electrostatic induction, electromagnetic induction, electromagnetic pulse radiation, lightning overvoltage invasion, lightning counterattack, etc. (collectively referred to as induced lightning), causing damage to buildings, equipment parts, or personal casualties. The severity of...

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The difference between a surge protector and a lightning arrester

the arrester has several voltage levels, from 0.38kV low voltage to 500kV ultra-high voltage, and the surge protector generally only low-voltage products; the lightning arrester is installed in a system, to prevent the direct invasion of lightning waves, and a surge protector is mostly installed in the secondary system, is in the lightning arrester to eliminate the direct invasion of lightning waves, or the lightning arrester will not eliminate the lightning wave clean when supplementary measures; the lightning arrester is to protect electrical equipment, and the surge protector is mostly to protect electronic instruments or meters; because the arrester...

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Technology & Application Review of Arresters

There are three types of lightning arresters used to protect high-voltage power cables. The first type, with two names-dead angles (IEEE) or detachable (IEC) arrester-is mainly used in power distribution systems, usually in fixed cabinets. The second type (less common) is used for cable protection and is called a sheath voltage limiter. This is an air-insulated lightning arrester, mainly used for high-voltage cables, and can be found in submerged junction boxes or on risers near the cable terminals.

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Selection of Rated Current of High Voltage Fuse

Under normal circumstances, when the fuse is installed in indoor high-voltage switchgear, the rated current of the fuse is selected according to 1.5 to 1.8 times the rated full load current of the transformer. This is mainly because the transformer can be long-term under 1.1 times the rated power Work, short-term operation for 20 minutes at 1.3 times the rated power of the transformer, and the fuse must avoid the impact of the transformer closing inrush current (the closing inrush current is about 10 to 20 times the transformer rated current for 0.1 seconds) on the fuse melt. This selection...

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Problems frequently encountered in rural distribution transformers (2)

Large voltage and load changes, improper adjustment of gears When the magnitude of the grid voltage changes greatly or the load changes greatly, the voltage on the low-voltage side of the distribution transformer will be too low or too high. At this time, we need to adjust the voltage regulation tap switchgear of the distribution transformer to Ensure that the voltage on the low-voltage side of the distribution transformer is within the allowable range. If the contacts of the tap changer are in poor contact during adjustment, when the distribution transformer is put into operation, the moving and static contacts will...

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Questions and Answers on Construction Technology of Overhead Transmission Lines

What are the main components of high-voltage overhead transmission lines? Wires, insulators, fittings, towers, foundations, ground wires, and grounding devices. How many types of towers are commonly used in high-voltage overhead transmission lines according to the nature of the force? How about the number of loops? According to the nature of the force, it can be divided into (1) overhanging pole and tower; (2) tensile pole and tower; According to the number of circuits, it is divided into (1) single circuit pole tower; (2) double circuit pole tower; (3) multi-circuit pole tower; What is a compact line? The so-called compact line refers to...

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Overvoltage Protection of Series Capacitor Banks

The series capacitor bank is mainly composed of a capacitor and its protection system and increases the power flow on the existing system by reducing the line impedance. Their first application dates back to 1928 when GE installed such energy storage (rated 1.2 MVar) at the Ballston Spa substation of the New York Power and Lighting Company’s 33 kV grid. Since then, series capacitor banks have been installed in systems around the world. Metal oxide varistors (MOV) provide overvoltage protection and are therefore an important part of these groups.

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HDPE Pin type insulator

A high-density polyethylene insulator(HDPE insulator) or plastic insulator can be used in the overhead electrical distribution system, compacted, or conventional distribution aerial nets. It suits polluted areas or salty coastal areas in the tropical zone. HDPE insulators can be applied with jacketed or bare overhead conductors, aluminum, or copper. Mainly applied in the electrical system of 15KV, 25KV, and 35KV. HDPE Insulator has following advantages -Excellent Track-Resistant -High Chemical Resistance -Unbreakable and Light Weight -Easiest Handling and Transportation -Low Initial Cost -Long Service Life -Durable Metal Treads -Water-Repelling Surface -High resistance to traction, flexion, and impact -May be fixed by the elastomeric ring or pre-shaped plastic lace

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Chairman Wu’s New Year Speech 2022

As a poem writes “Youth never comes again and time never waits anyone”, the year of 2021 has passed. Looking back over what we have experienced in the past 2021, I feel it is hard to describe it in words. What we are experiencing is the same as what we suffered last year with strict epidemic control, severe environment protection policy, rising raw material price, and soaring sea freight badly affecting our export business. What happened at home and abroad in 2021 and how the government policy changed to make people engaged in industry study the policies and make decisions...

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