Lightning arrester is a device used to protect substation equipment from lightning shock wave. When the lightning shock wave of the incoming substation along the route exceeds the protection level of the arrester, the arrester first discharges, and the lightning current is safely introduced to the earth through a good conductor. The grounding device is used to limit the lightning voltage amplitude below the lightning impact level of the protected equipment, so that the electrical equipment is protected.
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Surge protection device (surge protection device), also known as lightning protection device, referred to as (SPD) is suitable for AC 50\/60HZ, rated voltage 220V to 380V power supply system (or communication system), for indirect lightning and direct lightning impact or other instantaneous overvoltage surge protection, suitable for domestic residential, tertiary industry and industrial field surge protection requirements. It has the protection mode of relative phase, relative ground, relative center line, center line to ground and its combination.
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1, the application field can be divided from the voltage level.
The rated voltage of the arrester is <3kV to 1000kV, low voltage 0.28kV, 0.5kV.
Rated voltage of surge protector ≤ 1.2kV, 380, 220~10V~5V.
2. Different protected objects
The arrester is to protect the electrical equipment, and the SPD surge protector is generally to protect the secondary signal circuit or the end power supply circuit for electronic instruments and meters.
3, the insulation level or pressure level is different
The voltage level of electrical equipment and electronic equipment is not an order of magnitude, and the residual voltage of the overvoltage protection device should match the voltage level of the protected object.
4, the installation position is different
The arrester is generally installed on the primary system to prevent the direct intrusion of lightning waves and protect the overhead lines and electrical equipment; The SPD surge protection device is mainly installed on the secondary system, which is a supplementary measure when the lightning arrester eliminates the direct intrusion of the lightning wave, or the lightning arrester does not eliminate the lightning wave. Therefore, the arrester is installed at the inlet line; SPD is usually installed at the terminal outlet or signal loop.
5, different flow capacity
Because the main function of lightning arrester is to prevent lightning overvoltage, its relative current capacity is large. For electronic equipment, its insulation level is much smaller than that of electrical equipment in the general sense, so SPD is required to protect against lightning overvoltage and operating overvoltage, but its current capacity is generally not large. (SPD is generally at the end, not directly connected with the overhead line, after the upper level of the current limiting effect, lightning current has been limited to a low value, so the SPD with small flow capacity can completely play a protective role, the flow value is not important, the important thing is residual pressure.)
6, the surge protector is suitable for the fine protection of low-voltage power supply system.
Power surge protector Because of the large distance between the terminal device and the previous surge protector, it is easy to generate oscillating overvoltage or other overvoltages on the line. Fine power surge protection for terminal equipment, combined with the pre-surge protector, the protection effect is better.
7, material is different
The main material of the arrester is mostly zinc oxide (one of the metal oxide rheostat), and the main material of the surge protector is different according to the level of surge resistance and graded protection (IEC61312), and the design is much more sophisticated than the ordinary lightning protection device.
8. Technically speaking
Electrical terminal protection refers to a measure to protect the terminal equipment in the electrical system. Terminal equipment includes cables, switches, plugs, sockets, etc., which play the role of connecting and distributing electrical energy in the electrical system.
The purpose of electrical terminal protection is to protect these devices from electrical failure, overload, short circuit and other factors, so as to ensure the safe operation of the electrical system. Common electrical terminal protection measures include overload protection, short circuit protection, grounding protection and so on.