The most primitive surge protector device appeared in the late 19th century, but was used for overhead transmission lines to prevent insulation and power outages, and to prevent damage caused by lightning strikes. In the 1920s, aluminum surge protectors, oxide film surge protectors, and pill surge protectors emerged. Pipeline surge protectors appeared in the 1930s, silicon carbide lightning arresters in the 1950s, and metal oxide surge protectors in the 1970s.

Surge protectors are activated overseas. By 1992, the industrial control standard 35mm rail card connection SPD lightning protection module representing Germany and France began to be introduced on a large scale into China. Subsequently, integrated box type power circuit breakers representing the United Kingdom and the United States also began to be activated.

A typical surge protector adopts fire prevention and extinguishing technology, which can analyze and solve the causes of EDM through contact connection and current cutting process. This technology involves the generation and extinguishing of electric arcs. The surge protector also has a built-in circuit breaker, which protects the circuit together with the circuit breaker, completely preventing fires.

With the improvement of scientific and technological level, more and more electronic devices have been researched and applied. Therefore, the country has formulated the corresponding "Management Measures for Lightning Protection Facility Testing", which stipulates the application standards and requirements for surge protectors in various scenarios. During thunderstorms, it is necessary to thoroughly inspect and test the lightning protection facilities and equipment in various regions, and timely record and report them.

But the more electronic devices develop, the more susceptible they are to lightning strikes, and the higher the requirements for lightning protection devices. Surge protectors can be installed through multiple steps to meet the tolerance requirements of information system equipment, but if multiple levels need to be matched, it is recommended to use the same product from the same manufacturer.

Product Introduction of Power Surge Protector for Lightning Protection

Power surge protector for lightning protection: According to the three-level lightning protection principle, the protection measures required for power supply and equipment are divided into three stages. Install a first level lightning protection device in the entire distribution cabinet, select a power lightning protection device with a relatively large current (maximum discharge current of 80KA to 160KA depending on the situation), install a second level power lightning protection device (left and right 40KA) in the subordinate area distribution box, and finally install a third level power lightning protection device (10KA to 40KA) on the front of the equipment

The coverage range of network signal lightning protection devices: overvoltage protection for lightning and electromagnetic pulses used in 10/100Mbps switches, hubs, routers and other network equipment; Protection of network switches in network rooms; Protection of network server rooms; Other network computer rooms with network interface equipment protection; The 24 port integrated minefield is mainly used as a centralized protection signal surge protector for multiple signal channels in integrated network cabinets and segmented switch cabinets.

Signal surge protector: mainly used for point-to-point protection of video signal equipment, protecting various video transmission equipment from the hazards of induced lightning strikes and surge voltages in signal transmission lines. The same applies to RF transmission at the same operating voltage. The integrated multi port video minefield is mainly used for centralized protection of control equipment such as hard disk recorders and video cutters in integrated control cabinets.

The difference between a first level surge protector and a second level surge protector

Surge protectors, also known as lightning protection devices, are electronic devices that provide safety protection for various electronic equipment, instruments, and communication lines. Surge protectors can circulate through channels in a very short period of time in the event of sudden maximum current or voltage caused by external interference in circuits or communication lines, preventing surge damage to other devices in the circuit.

Surge protectors, AC 50/60HZ, rated voltage of 220V to 380V, are required for surge protection in households affected by indirect lightning, direct lightning, or other transient overvoltage and overcurrent in power systems, as well as in the tertiary industry and other sectors.

Lightning discharge can occur between clouds, within clouds, or between clouds and ground; In addition, due to the use of many high-capacity electrical equipment, internal surges have become a focus of attention for power supply systems (Chinese low-voltage power supply system standard: AC 50Hz 220/380V) and electrical equipment, as well as lightning protection and surge protection.

The lightning discharge between clouds and the ground is composed of one or more individual lightning strikes, which carry a certain high value and short period of current. A typical lightning discharge consists of 2-3 lightning strikes, with an interval of approximately one twentieth of a second between each lightning strike.

Adaptive Method for Specific Selection of Power Surge Protectors

When entering the AC power wiring of the building and crossing with LPZ0A or LPZ0B and LPZ1 areas (such as the main distribution box of the line), the surge protector in Class I testing or the surge protector in Class II testing must be set to Level 1 protection. You can associate surge protectors in Class II or III testing with subsequent protection zones such as distribution boxes, electronic equipment room distribution boxes, etc., and set them to the back protection level. Special and important electronic information equipment power ports can be equipped with surge protection programs for Class II or III testing, and provide fine protection. Use DC power supply information equipment and install corresponding DC power line surge protectors according to the working voltage requirements. 2. The setting series of surge protectors must consider factors such as protection distance, length of surge protector connecting wires, and rated impulse voltage (UW) of the protected equipment. All levels of surge protectors must be able to withstand the expected discharge current at the installation point, and the effective protection level UP/F must be lower than the UW of the equipment in that category

If the length of the line between the voltage switch surge protector and the voltage limiting surge protector is less than 10 meters, and the efficiency of the line length between the voltage limiting surge protectors is less than 5 meters, decoupling devices must be installed between the two levels of surge protectors. If the surge protector has the function of automatically adjusting energy, there is no limit to the length of the line between surge protectors. Surge protectors must have overcurrent protection devices and degradation display functions.

Can the power surge protector be replaced only after it malfunctions?

The function of a power surge protector is to protect various electrical equipment in the power system from lightning induced electrical overvoltage, operational overvoltage, power frequency transient overvoltage, and damage. The main types of surge protectors are protection intervals, valve type surge protectors, and zinc oxide surge protectors. The protection interval is mainly used to limit atmospheric overvoltage and is generally used to protect the network segments entering the distribution system, lines, and substations. Power surge protectors are used to protect substations and power plants. Mainly used to limit atmospheric overvoltage below 500KV. Also used to limit the internal pressure of Ehv systems. Overpressure or internal overpressure protection. According to their usage, surge protectors can be classified into the following types:

1. Switching power surge protector: It operates in a high impedance manner without transient overvoltage, but when responding to lightning transient overvoltage, the impedance suddenly drops to a low value, causing lightning current to pass through. The device includes discharge gaps, gas discharge tubes, thyristors, etc.

2. Voltage limited power surge protector: operates as a high impedance device without temporary overvoltage, but as the overcurrent and voltage increase, the impedance continuously decreases, and the current and voltage characteristics are very nonlinear. These devices use equipment including zinc oxide, varistors, suppression diodes, avalanche diodes, and other power surge protectors, with most types of pressure limiting.

Surge protector for shunt or turbulent power supply

Diversion type: When parallel with the protection device, the impedance of the lightning pulse is low, and the impedance of the normal operating frequency is high.

Turbulence: When connected in a row with protective equipment, lightning pulses indicate high impedance, while normal operating frequencies indicate low impedance.

Power surge protector is a protective device for low-voltage power supplies. If lightning or other factors cause high power supply voltage, the equipment in the circuit may be damaged. The function of a power surge protector is to release a large amount of pulse energy in the circuit caused by induced lightning strikes in the shortest possible time, thereby protecting user equipment in the circuit. The location of power surge protectors belongs to electronic products and their service life is limited. The service life of power surge protectors is related to many factors. In addition to manufacturing quality, sealing failure, and other external factors, the aging rate of surge protective film is also a key factor affecting its service life.

Introduction

Surge protector, also known as power lightning arrester, is an electronic system that provides security measures for various electronic devices, instruments, and communication lines. When there is a sudden peak current or voltage in the control circuit or communication network of electrical equipment due to external influences, surge protectors can conduct and separate in a very short time, thereby preventing the harm of surges to other devices in the control circuit.

Surge protector, suitable for communication and exchange in power supply and distribution systems with a frequency of 50/60HZ and a rated voltage of 380V/380V, to protect against indirect lightning strikes, immediate lightning strikes, or other transient overvoltage surges. It is applicable to the regulations for surge protection in residential, tertiary, and industrial production industries.

development

The initial surge protector with a horn shaped gap appeared in the late 19th century, used to empty power lines to prevent lightning strikes from damaging equipment insulation and causing power outages. In the 1920s, aluminum surge protectors, air oxide film surge protectors, and pill surge protectors emerged. In the 1930s, tubular surge protectors emerged. Carbon carbon composite material power lightning arresters emerged in the 1950s. In the 1970s, hydroxide surge protectors emerged again. Contemporary high-voltage surge protectors are not only used to limit the overvoltage caused by lightning strikes in power supply systems, but also to limit the overvoltage caused by actual operation of system software. Since 1991, the industrial automation standard 35mm slide rail card type withdrawable SPD power lightning arrester, which means etiquette and law, has been introduced to China on a large scale. Later, the integrated box type power lightning arrester, which means the United States and the United Kingdom, also entered China.

categorize

SPD is an essential device for lightning safety protection of electronic devices. Its function is to limit the instantaneous overvoltage that enters high-voltage lines or coaxial cables for data signals within the voltage range that the equipment or system software can bear, or to discharge strong lightning currents into the ground, protecting the protected equipment or system software from impact.

Divided by principle

According to their principles, SPDs can be classified into voltage power switch type, voltage limiting type board, and combination type.

⑴ Voltage power switch type SPD. When there is no instantaneous overvoltage, it exhibits high characteristic impedance. Once it responds to the instantaneous overvoltage caused by lightning strikes, its characteristic impedance suddenly changes to low characteristic impedance, allowing for lightning current. It is also known as a "short-circuit fault power switch type SPD".

⑵ Pressure limiting plate SPD. When there is no instantaneous overvoltage, it has a high characteristic impedance, but as the surge current and voltage increase, its characteristic impedance will continue to decrease. Its current and voltage characteristics are clearly discrete systems, sometimes referred to as "clamp type SPD".

⑶ Combination SPD. Composed of voltage power switch type components and voltage limiting plate components, it can display information as either voltage power switch type or voltage limiting plate, or both, depending on the characteristics of the applied voltage.

Classified by main purpose

1. Switching power supply circuit SPD

Because the kinetic energy of lightning strikes is extremely large, it must be released gradually into the ground according to the classification of levels. Install surge protectors or voltage limiting plate surge protectors classified according to Level I classification experiments as the first level protection in the non protected area (LPZ0A) or at the intersection of the protected area (LPZ0B) and the first protection area (LPZ1), to release the shock lightning current, or to release the maximum kinetic energy transmitted when the transmission line of the switching power supply is immediately struck by lightning. Install voltage limiting plate surge protectors at the intersection of various system zones (including LPZ1 zone) after the first protection zone, as second, third or higher level protection. The second level protector is a safety protection device for residual voltage and magnetic induction in the area of the previous protector that is struck by lightning. When a large amount of lightning kinetic energy is generated in the front and absorbed, there is still a very large amount of kinetic energy that is transmitted back to the equipment or the third level protector, which must be further digested and absorbed by the second level protector. In addition, the transmission route through the first level power lightning arrester will also be magnetically induced to be struck by electromagnetic pulse radiation sources. When the route is sufficiently long, the kinetic energy of the magnetic induction lightning becomes increasingly abundant, and the second level protector must further release the kinetic energy of the lightning strike. The third level protector provides protection based on the residual lightning kinetic energy of the second level protector. According to the pressure resistance level of the protected equipment, if the secondary lightning protection can ensure that the limited voltage is lower than the equipment's pressure resistance level, only secondary protection must be carried out; If the pressure resistance level of the equipment is low, it will require four or more levels of protection.

To select SPD, one must first master some key parameters and principles.

⑴ The 10/350 μ s wave is a simulated shock wave type with high kinetic energy; The 8/20 μ s wave is a waveform used for simulating magnetic induction and lightning transmission caused by lightning strikes.

⑵ The allowable charging and discharging current In refers to the highest value current that passes through the SPD and 8/20 μ s current wave.

⑶ The larger charge and discharge current Imax, also known as the larger total flow rate, refers to the larger charge and discharge current that can be sustained by an 8/20 μ s current wave surge SPD in one application.

⑷ Large continuous pressure resistance Uc (rms) refers to the sustained release of a large AC voltage amplitude or DC voltage on the SPD.

⑸ Residual voltage Ur refers to the residual voltage value at the rated charging and discharging current In.

⑹ Qualitative analysis of the protection voltage Up: The main parameters of the voltage characteristics between SPD limited terminal blocks can be selected from the selection value directory, and should exceed the maximum value of the limited voltage.

The key release of voltage power switch type SPD is 10/350 μ s current wave, while the key release of voltage limiting board SPD is 8/20 μ s current wave.

2. Data signal route SPD

The data signal line SPD is actually a high-voltage lightning arrester for data signals, installed in the data signal transmission line. It is generally developed at the front end of the equipment to protect the equipment afterwards and prevent lightning waves from entering and damaging the equipment from the data signal line.

1) Selection of Voltage Protection Level (UP)

The UP value cannot exceed the rated current of the protected equipment's impulse voltage, and UP requires excellent coordination between the SPD and the insulation layer of the protected equipment.

In the bottom voltage power supply system equipment, the equipment should have a certain ability to withstand surge work, that is, the ability to withstand impact overvoltage work. When it is not possible to obtain the anti surge overvoltage values of various devices in the 220/380V three-phase system software, the index values given in IEC60664-1 and GB50057-1994 (2000 edition) can be used.

2) Selection of allowable differential charging and discharging current In (impulse current carrying capacity)

The highest current passing through SPD and 8/20 μ s current wave. Used for conducting Level II classification experiments on SPDs, as well as for preparing for Level I and Level II classification experiments on SPDs.

In fact, In is the maximum value of impulse current that SPD can withstand according to the required frequency (usually 20 times) and required waveform (8/20 μ s) without causing actual damage.

3) Selection of Maximum Charge and Discharge Current Imax (Ultimate Impulse Carrying Capacity)

The highest current passing through SPD and 8/20 μ s current wave is used for Class II classification experiments. Imax and In have many similarities, as they both conduct Level II classification experiments on SPDs using the highest current of an 8/20 μ s current wave. The differences are also significant, Imax only conducted one impact test on SPD, and after the experiment, SPD did not produce actual damage; And in can conduct 20 such experiments, and the SPD cannot have actual damage after the experiment. Therefore, Imax is the specified value for impulse current, and therefore larger charge and discharge currents are also known as the ultimate impulse current carrying capacity. Obviously, Imax>In。

Installation method of surge protector

1. Basic Installation Regulations for SPD

The surge protector is installed on a 35mm standard slide rail

For mobile SPDs, the basic installation should follow the following process:

1) Clarify the relative path of charging and discharging currents

2) Identify the transmission lines that cause additional voltage drops at the terminal devices of the equipment,.

3) To prevent redundant magnetic induction control circuits, the PE electrical conductor of each device should be labeled,

4) Create an equipotential connection between the device and SPD.

5) To carry out multi-level SPD with harmonious kinetic energy

In order to limit the magnetic induction coupling between the protected part after installation and the part of the equipment that will not be protected, certain precise measurements need to be carried out. By separating the magnetic induction source from the abandoned power circuit, selecting the control circuit perspective, and limiting the closed circuit area, mutual inductance can be reduced,

When the current carrying capacity of the transmission line is part of a closed circuit, the control circuit and magnetic induction voltage decrease due to the proximity of the transmission line to the power circuit.

Generally speaking, it is better to separate the protected and unprotected transmission lines, and they should be separated from the wire joints. In addition, in order to prevent transient orthogonality and coupling between power cables and electrical cables, necessary precise measurements should be carried out.

Installation and wiring method of surge protector

2. Selection of SPD wire connector diameter

Mobile phone charging cable: specified to be over 2.5mm2; When the length exceeds 0.5 meters, it is stipulated to exceed 4mm2. YD/T5098-1998。

Power plug: When the cross-sectional area of the phase wire is S ≤ 16mm2, use S for the grounding wire; when the cross-sectional area of the phase wire is 16mm2 ≤ S ≤ 35mm2, use 16mm2 for the grounding wire; When the cross-sectional area of the phase line is S ≥ 35mm2, the grounding wire is specified as S/2; Article 2.2.9 of GB50054

Basic parameters of surge protectors

1. Allowable voltage Un: The rated voltage of the protected system software is consistent. In the information technology system software, this parameter indicates the type of protector that should be used, and it indicates the amplitude of the AC or DC voltage for communication.

2. Rated voltage Uc: It can be released at a specific end of the protector for a long time without causing a change in the characteristics of the protector or triggering a large voltage amplitude of the protective components.

3. Rated charging and discharging current Isn: When the protective device is subjected to 10 standard lightning wave impacts with a waveform of 8/20 μ s, the protective device is subjected to significant impact electricity