What are the classifications of power surge protectors? What are the names of the main equipment for

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Surge protection device is an indispensable device for lightning protection of electronic equipment, and was often called in the past"Surge arrester"or"Overvoltage protectors"The English abbreviation is SPD. The function of the surge protector is to limit the instantaneous overvoltage that enters the power line and signal transmission line within the voltage range that the equipment or system can bear, or discharge the strong lightning current into the ground to protect the protected equipment or system from damage caused by impact.

The type and construction of a surge protective device varies depending on the application, but it should contain at least one nonlinear voltage limiting element. The basic components used for surge protective devices are: discharge gap, gas discharge tube, varistor, suppression diode and choke coil, etc.

1. Classification of SPD:

1. According to the working principle:

1. Switching type: Its working principle is that when there is no instantaneous overvoltage, it is high impedance, but once it responds to the lightning instantaneous overvoltage, its impedance suddenly changes to a low value, allowing the lightning current to pass through. When used as such devices, the devices are:

Discharge gaps, gas discharge tubes, thyristor transistors, etc.

2. Voltage limiting type: its working principle is that when there is no instantaneous overvoltage, it is high resistance, but with the increase of surge current and voltage, its impedance will continue to decrease, and its current and voltage characteristics are strongly nonlinear. The devices used as such devices are:

Zinc oxide, varistors, suppression diodes, avalanche diodes, etc.

3 Split or choke.

Shunt type: Connected in parallel with the protected equipment, it presents low impedance to lightning pulses and high impedance to normal operating frequencies.

Choke type: In series with the protected equipment, it presents a high impedance to lightning pulses and a low impedance to normal operating frequencies.

The devices used as such devices are: choke coils, high-pass filters, low-pass filters, 1 4-wavelength short-circuits, etc.

According to the use: (1) power protectors: AC power protectors, DC power protectors, switching power supply protectors, etc.

2) Signal protectors: low-frequency signal protectors, high-frequency signal protectors, antenna feeder protectors, etc.

Hello dear, glad to answer for you. Kiss, lightning rod, also known as lightning protection needle, lightning rod, is used to protect buildings, tall trees and old trees to avoid lightning strikes. A flash receiver is installed at the top of the protected object and connected to the underground drainage network with a wire that meets the specifications.

The specifications of lightning rods must meet the national standards, and the height specifications of the lightning rods required for each lightning protection category are different.

There are two types of surge protectors: high-voltage and low-voltage surge protectors, and this section introduces the surge protectors (surge protector SPDs) in low-voltage power distribution systems

There are many types of surge protectors, and there are more than 100 kinds of lightning protectors in the Chinese market, and how to classify different brands and models of lightning protectors may be in front of us.

From the composition structure; There are several lightning arresters on the market now:

1) Clearance category——— open clearance, closed clearance.

2) Discharge tubes——— open discharge tubes, sealed discharge tubes, 3) Varistors - monolithic, multi-piece.

4) Suppression diodes.

5) Varistor gas discharge tube combination ---simple combination, complex combination 6) silicon carbide.

According to its protection properties, it can be divided into: open-circuit arrester, short-circuit arrester or switch type, voltage limiting type;

According to the working state (installation form), it can be divided into: parallel arrester and series arrester.

In general, there are three main forms of lightning strikes: one is the rapid discharge between the charged clouds and a certain point on the earth, which is called "direct lightning". The second is that the charged cloud layer is charged with a heterogeneous charge in a certain area of the ground due to electrostatic induction.

When direct lightning occurs, the cloud charge disappears quickly, and some areas of the ground due to the large dispersion resistance, resulting in local high voltage, or due to the direct lightning discharge process, the strong pulse current to the surrounding wires or metal objects to produce electromagnetic induction of high voltage resulting in the phenomenon of lightning strike, called "secondary lightning" or "induced lightning". The third is the "spherical mine".

Tubular lightning arrester.

The tubular arrester is actually a kind of protection gap with high arc extinguishing ability, which is composed of two series clearances, one gap is in the atmosphere, called the outer clearance, and its task is to isolate the working voltage and avoid the gas production pipe from being burned out by the power frequency leakage current flowing through the pipe; The other is installed in the trachea, called the internal clearance or arc extinguishing gap, and the arc extinguishing capacity of the tubular arrester is related to the size of the power frequency freewheel. This is a kind of protection gap type lightning arrester, which is mostly used in power supply lines for lightning protection.

Valved surge arrester.

The valve-type arrester is composed of a spark gap and a valve resistor, and the valve resistor is made of special silicon carbide. Die resistors made of silicon carbide can effectively protect against lightning and high voltage, and protect equipment. When there is a lightning high voltage, the spark gap is broken down, and the resistance value of the valve resistor decreases, which introduces the lightning current to the earth, which protects the cable or electrical equipment from the harm of lightning current.

Under normal circumstances, the spark gap will not be broken down, and the resistance value of the valve plate resistance is high, which will not affect the normal communication of the communication line.

Zinc oxide arrester.

Zinc oxide arrester is a lightning protection equipment with superior protection performance, light weight, pollution resistance and stable performance. It mainly uses the good nonlinear volt-ampere characteristics of zinc oxide to make the current flowing through the arrester at normal operating voltage very small (micro-ampere or milliampere level); When the overvoltage acts, the resistance drops sharply, dissipating the energy of the overvoltage to achieve the effect of protection. The difference between this arrester and the traditional arrester is that it has no discharge gap, and uses the nonlinear characteristics of zinc oxide to play the role of discharge and breaking.

The above introduces several lightning arresters, each of which has its own advantages and characteristics, and needs to be used for different environments in order to have a good lightning protection effect.

There are two types of indoors: indoor and outdoor.

There are four types of lightning: direct lightning, electromagnetic pulse, spherical lightning, and cloud flash.

1) Direct lightning strike.

Direct lightning strikes are formed by electrical discharges between clouds and ground protrusions. Direct lightning strikes can injure and kill people and animals in an instant. Huge lightning currents flow into the ground, resulting in extremely high ground voltages at the lightning strike point and the metal parts connected to it, which may directly lead to electric shock accidents involving contact voltage or step voltage.

2) Spherical mines.

Spherical lightning is a spherical, reddish or extremely bright white fireball that travels at a speed of about 2 ms. Spherical mines can penetrate into the room through doors, windows, chimneys and other passages, which is extremely dangerous.

3) Lightning induction, also known as induction lightning.

There are two types of lightning induction: electrostatic induction and electromagnetic induction. Electrostatic induction is caused by a thundercloud approaching the ground and inducing a large amount of anisotropic charge on top of a ground protrusion. When the thundercloud is discharged from other parts, the charge at the top of the protrusion loses its restraint and propagates extremely quickly along the protrusion in the form of lightning waves.

Electromagnetic induction is caused by a powerful magnetic field caused by a large lightning current that changes rapidly in the surrounding space after a lightning strike. This magnetic field can induce high voltages on nearby metal conductors, causing secondary discharges to the human body and thus damaging electrical equipment.

4) Lightning intrusion waves.

Lightning shock waves are lightning waves that are rapidly propagating along or in pipelines due to impulse voltages generated on overhead lines or on metal pipes in the air as a result of lightning strikes. Its propagation velocity is 3 108m s. Lightning can destroy the insulation of electrical equipment, causing high voltage to flow into low voltage, causing serious electric shock accidents.

For example, during a thunderstorm, the indoor electrical equipment is suddenly damaged or damaged, and a person is suddenly electrocuted to death when using electrical appliances or playing in the house.

Types of lightning:

Burst lightning.

There are four types of lightning: direct lightning, electromagnetic pulse, spherical lightning, and cloud flash. Among them, direct lightning and spherical lightning will cause harm to people and buildings, while electromagnetic pulse mainly affects electronic equipment, mainly caused by induction; Cloud flashes are the least harmful to humans because they occur between two clouds or on both sides of a cloud.

Direct lightning is to gather a lot of electric charges on the cloud, and a large number of electric charges have to find a channel to vent, sometimes it is a building, sometimes it is an iron tower, sometimes it is a person in an open place, so these people or objects become a channel for the discharge of electric charges, and the person or building is injured. Direct lightning is the most powerful lightning, while spherical lightning is less powerful than direct lightning.

The law of lightning activity:

1 The general conditions for lightning activity are as follows:

1) Geological conditions: When the relative value of soil resistivity is small, it is conducive to the rapid accumulation of electric charges. Places with low local resistivity are susceptible to lightning strikes; Places with sudden resistivity changes and underground conductive deposits are susceptible to lightning strikes; In fact, the resistivity of the grounding grid will increase the probability of lightning strikes.

2) Topographic conditions: the direction of the valley is consistent with the wind direction, and the wind outlet or downwind valley is prone to lightning strikes; There is a high probability that the slopes of the mountains near the lake or sea will be struck by lightning.

3) Ground conditions: It is conducive to the establishment of a good discharge channel between thunderstorm clouds and the earth. isolated buildings in open spaces, tall buildings in complexes that are susceptible to lightning strikes; Large trees, receiving antennas, and transmission lines in mountainous areas are susceptible to lightning strikes; In line with the characteristics of tip discharge, the probability of lightning strikes will also increase after the base station tower is completed.

2 Based on engineering experience, the following sites are likely to have a high probability of lightning damage:

1) The place where the soil resistivity R10 at a depth of 10m has a sudden change.

2) At the junction of rocky mountains, paddy fields and rivers, at the boundary of mineral deposits, at the boundary of mountains and forests, and at some geological fault zones.

3) The slope of the mountain or the windward slope facing the vast water.

4) Higher, isolated mountain tops.

5) Locations where lightning damage has occurred repeatedly in the past.

6) Isolated towers and cables, near towering buildings and other grounding protection devices.

Lightning is divided into bai direct strikes.

Induction thunder du and ball thunder.

Direct lightning is when a charged cumulus cloud approaches the DAO ground to a certain extent.

Strong response to a strong discharge with a ground target. Each discharge of direct lightning includes three stages: pilot discharge, main discharge, and afterglow. About 50 percent of direct lightning strikes have a repetitive discharge characteristic. Every lightning strike has.

Three or four shocks to dozens of impacts.

Induction lightning is also known as lightning induction, which is divided into electrostatic induction lightning and electromagnetic induction lightning. Electrostatic induction lightning is due to the charge cumulus inducing a large number of charges on the top of overhead line wires or other conductive protrusions, after the charged cumulus and other objects are discharged, the induced charges lose their binding, in the form of high-current, high-voltage shock waves, along the propagation of wire wires or conductive protrusions. Electromagnetic induced lightning is due to the high induced electromotive force generated by a rapidly changing strong magnetic field in the surrounding space when lightning is discharged.

Ball thunder is a fireball of red, orange, white, or other colors of light formed when lightning is discharged. From an electrical point of view, the ball mine should be a mass of charged gas in a special state.

In addition, both direct and induced lightning can produce lightning shocks that propagate rapidly along the lines or pipelines in both directions of the overhead line or on the aerial metal pipeline.

Types of lightning:

Lightning is divided into direct strike lightning, induction lightning, and ball lightning.

The selection and adaptation of power surge protector should pay attention to the following aspects:

2.The number of stages of the surge protector should be comprehensively considered such as the protection distance, the length of the connecting wire of the surge protector, and the rated value of the impulse voltage of the protected equipment (UW). Surge protectors at all levels should be able to withstand the expected discharge currents at the point of installation, and their effective protection level up f should be less than the UW of the corresponding class of equipment

3.When the line length between the voltage-switching surge protector and the voltage-limiting surge protector is less than 10 meters, and the line length efficiency between the voltage-limiting surge protector is 5 meters, a decoupling device should be installed between the two-stage surge protector. When the surge protector has the function of energy automatic mating, the length of the line between the surge protector is not limited.

The surge protector should have an overcurrent protection device and a deterioration display function.

4.According to the lightning protection level, the inrush current and nominal discharge current parameters of the surge protector used in the power supply line are as follows:

Power line surge protector inrush current and nominal current.

5.When the power surge protector is installed in various positions, the connecting wires of the surge protector should be short and straight, and its total length should not be Daewoo meters. The effective protection level should be less than the impulse voltage rating of the equipment.

6.The length of the line between the installation position of the power line surge protector and the protected equipment is 10 meters.

7.When the length of the line between the first-level power surge protector and the protected equipment at the entrance is greater than the specified value, the surge protector should be added at the distribution box of the distribution line or at the protected equipment. When multi-level surge protectors are installed on a line, the energy coordination between them should be considered.