1. Arresters have several voltage levels, from 0.38kv low voltage to 500kV UHV, while surge protective devices are generally only low voltage products;
2. Most of the arresters are installed on the primary system to prevent the direct invasion of lightning wave, while most of the surge protectors are installed on the secondary system, which is a supplementary measure after the arrester eliminates the direct invasion of lightning wave, or when the arrester does not eliminate the lightning wave completely;
3. Arrester arrester is used to protect electrical equipment, while surge protector is mostly used to protect electronic instruments or meters;
4. Because the arrester is connected to the electrical primary system, it should have enough external insulation performance, and the appearance size is relatively large. Because the surge protector is connected to the low voltage, the size can be very small.
Surge protective device 1. Frequency conversion control cabinet must be added; 2. Control cabinet using vacuum circuit breaker must be added; 3. Incoming switch of power supply system must be added
4. Other control cabinets may not be added. Of course, if there is budget space for safety, they can be added
Surge protective devices are generally divided into two types: motor protection type and power station protection type!
The by series surge protective device adopts a varistor with excellent nonlinear characteristics. Under normal conditions, the surge protective device is in a very high resistance state, and the leakage current is almost zero, so as to ensure the normal power supply of the power system arrester. When the overvoltage occurs in the power supply system, the stainless steel decoration and the surge protector will immediately conduct in nanoseconds to limit the amplitude of the overvoltage within the safe working range of the equipment. At the same time, the energy of the overvoltage is released. Subsequently, the protector quickly becomes high resistance state, so it does not affect the normal power supply of the power system.
Surge protection device (SPD) is an indispensable device in the lightning protection of electronic equipment. It used to be called "surge arrester" or "overvoltage protector", abbreviated as SPD in English. The function of surge protection device is to limit the transient overvoltage into 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, so as to protect the protected equipment or system from being damaged by impact.
The types and structures of surge protective devices are different according to different applications, but they should contain at least one nonlinear voltage limiting element. The basic components used in SPD include discharge gap, gas filled discharge tube, varistor, suppression diode and choke coil.
Post time: Jul-08-2021