Signal Surge Protective Device (SPD).It is a lightning protection device used to limit transient overvoltage and discharge inrush current in signal lines, and is mainly used to protect the lightning protection safety of various signal lines and equipment. The principle of signal surge protector is to use nonlinear components such as gas discharge tubes, varistors, Zener diodes and other nonlinear components to limit the excessive voltage on the signal line within a certain range, or shunt the surge current to the ground wire, so as to reduce or eliminate the damage to the protected equipment.
Dikai TechnologyAccording to the different types of protected lines, signal surge protectors can be divided into network signal surge protectors, monitoring signal surge protectors, control signal surge protectors, signal surge protectors, signal surge protectors, and explosion-proof signal surge protectorsand other types, each of which has many models, parameters, and different appearances.
The main function of the signal surge protector is twofold:
The first is to limit the transient overvoltage caused by induced lightning in the signal line. According to surveys, more than 80% of lightning strikes in electronic systems are caused by inductive lightning. Therefore, the wide application of microelectronic equipment in modern society should strengthen the induction lightning protection of electronic systems and install appropriate signal surge protectors.
The second is to limit the surge caused by the start and stop of the electronic system. In addition to the surge in the signal line, the most important cause of the surge in the signal line is the start-stop of the electronic equipment. This kind of surge is ubiquitous, and the appropriate signal surge protector installed on the line can effectively suppress the surge caused by the operation of the electronic system, and can effectively reduce the deterioration and failure of electronic sensitive devices, ensure the stability of the signal line, and prolong the service life of electronic equipment.
The selection of signal surge protector should be based on the characteristics and requirements of the protected signal line, and the following parameters should be comprehensively considered:
Rated Operating Voltage (UC):It refers to the maximum continuous working voltage that the signal surge protector can withstand when it is working normally, which shall not be less than the maximum working voltage of the protected line.
Rated Operating Current (in):It refers to the maximum continuous working current that the signal surge protector can withstand when it is working normally, which should not be less than the maximum working current of the protected line.
Rated discharge current (in):Refers to the maximum current value that the signal surge protector can withstand under the lightning impulse current of the standard 8 20 s waveform, which should be selected according to the lightning risk level and protection level of the protected line.
Protection voltage (up):It refers to the maximum voltage value at both ends of the line under the rated discharge current of the signal surge protector, which reflects the voltage limiting capacity of the signal surge protector and should be less than the withstand voltage value of the protected equipment.
Transfer Rate (vs):It refers to the degree of influence of the signal surge protector on the signal line, which reflects the insertion loss and signal attenuation of the signal surge protector, which should be greater than the transmission rate of the protected line.
Band Width (bw):It refers to the influence range of the signal surge protector on the signal line, which reflects the pass-frequency characteristics and signal distortion of the signal surge protector, and should be greater than the frequency band width of the protected line.
Ground Resistance (RG):Refers to the resistance value between the grounding terminal of the signal surge protector and the ground, which reflects the grounding effect of the signal surge protector, and should be as small as possible, generally not greater than 10.
Dikai TechnologyThe industry application solutions of signal surge protectors are mainly as follows:
Communication Industry:Signal surge protectors can be used to protect communication equipment and lines such as communication base stations, switches, routers, modems, optical fiber transceivers, and ** machines, and prevent damage or interruption to communication systems caused by lightning and other power interference.
Security industry:Signal surge protectors can be used to protect security equipment and lines such as surveillance cameras, video recorders, alarms, access controllers, sensors, etc., to prevent damage or failure to the security system caused by lightning and other power interference.
Industrial:Signal surge protectors can be used to protect industrial equipment and lines such as sensors, transmitters, actuators, controllers, meters, etc., from damage or malfunction of industrial systems caused by lightning and other power disturbances.
Power Industry:Signal surge protectors can be used to protect power equipment and lines such as energy meters, relays, transformers, switches, etc., to prevent damage or tripping to the power system caused by lightning and other power disturbances.
Transportation Industry:Signal surge protectors can be used to protect traffic equipment and lines such as traffic lights, navigators, radars, radios, etc., from lightning and other power disturbances that cause damage or accidents to the transportation system.
The national standard and case embodiment of signal surge protector mainly include the following aspects:
National standard: "Technical Specification for Lightning Protection of Electronic Information System of Buildings".GB50343-2012 is the authoritative national standard for signal surge protectors in ChinaIt stipulates the classification, selection, installation, testing, maintenance and other technical requirements of the signal surge protector, which is the basis for the design, construction and acceptance of the signal surge protector.
gb/t 18802.21-2004 Low Voltage Surge Protective Devices Part 21: Protective Device Performance Requirements and Test Methods for Signal Lines.
gb/t 18802.22-2004 Low Voltage Surge Protective Devices Part 22: Protective Device Installation Requirements for Signal Lines.
gb/t 18802.23-2004 Low Voltage Surge Protective Devices Part 23: Principles for the Selection and Application of Protectors for Signal Lines.
The examples of signal surge protectors are as follows:
Case 1: In order to improve the reliability of the power communication system, a power company installed signal surge protectors on its optical fiber communication lines. According to GB T 1880221-2004 requirements, selected in accordance with C1 level protection of fiber optic signal surge protector and in accordance with GB T 1880222-2004, which is installed at both ends of the optical fiber line and connected to the optical fiber terminal equipment. After installation, after the test of thunderstorm season, the fiber optic communication line did not have any failure, and the signal surge protector played a good protective role.
Case 2: In order to protect the safe operation of its signal system, a railway company installed a signal surge protector on its signal cable. According to GB T 1880221-2004 requested, selectedDikai TechnologySurge protective device for signal cables in accordance with class B1 protection and in accordance with GB T 1880222-2004, which is installed at both ends of the signal cable and connected to the signal equipment. After installation, after the test of many lightning strikes, the signal cable did not have any failure, and the signal surge protector effectively avoided the damage of lightning to the signal system.
Case 3: In order to improve the stability of its first system, a data company installed a signal surge protector on its first line. According to GB T 1880221-2004 requested, selectedDikai Technology** Signal surge protector in accordance with B2 protection and in accordance with GB T 1880222-2004, which is installed at both ends of the ** line, connected to cameras and monitors. After installation, after many times of lightning interference, the line did not appear any signal loss or blurred picture, and the signal surge protector effectively improved the picture quality and clarity of the monitoring system.