In low-voltage power supply systems, communication transmission systems, measurement and control systems, and computer network systems, there are many factors that can cause surge overvoltage. The common causes of surge overvoltage include lightning discharge, industrial operation, and electrostatic discharge. Among them, lightning discharge and industrial operation are the main causes of surge overvoltage. The surge overvoltage caused by different reasons varies in amplitude, energy, waveform, and repetition frequency.
The energy contained in surge overvoltage is enormous, and even for highly reliable industrial devices and other equipment, it can cause serious damage. Although surge overvoltage occurs only in the microsecond range, it can still destroy electronic circuits or breakdown printed circuit boards. The surge overvoltage caused by various reasons is the main cause of service interruption, data loss, and equipment damage in modern electronic devices, and some equipment damage often occurs when it is necessary to maintain uninterrupted operation. Some affected components of the system require the purchase of new equipment for replacement, while others require maintenance, which requires a significant amount of manpower and financial resources. In addition, the loss of some software and data will cause huge irreparable losses.
1. Classified by function
1.1 Switch type
Its working principle is that when there is no overvoltage, it has a high impedance. Once it responds to lightning instantaneous overvoltage, its impedance suddenly changes to a low resistance value, allowing lightning current to pass through. Devices used for such devices include discharge gaps, gas discharge tubes, etc., generally used for LPZOB-LPZ1
1.2 Pressure limiting type
Its working principle is that it has high impedance when there is no overvoltage, but its impedance gradually decreases with the increase of surge overcurrent and overvoltage, and its current voltage characteristics are strongly nonlinear. Devices used in this category include varistors TVS tubes and other devices can significantly reduce residual voltage on the power grid and divert lightning impulse currents.
1.3 Composite type
Composed of switch type devices and voltage limiting devices, their characteristics can manifest as switch type, voltage limiting type, or both depending on the applied voltage.
1.4 Fully enclosed type
Mainly used in high-altitude, humid and hot areas, with low temperature resistance and strong pollution resistance.
2. Classification by purpose
2.1 Power surge protector
There are two types of surge protectors used to protect low-voltage distribution systems: AC power surge protectors and DC power surge protectors.
2.2 Signal surge protector
Surge protectors used to protect signal transmission systems, including Ethernet series ISDN series, telephone line series, video series RS232 series RS422 series RS485 series and other major categories.
2.3 Industrial measurement and control system surge protector
Surge protectors used to protect industrial control and measurement systems can be divided into two categories: protecting two lines and protecting Sixian.
2.4 Non feed surge protector
There are three types of surge protectors used to protect wireless coaxial systems: broadband, microstrip, and narrowband.
2.5 New energy surge protectors
Used for wind power generation, photovoltaic power generation, photovoltaic new energy combiner boxes and other products, characterized by high impact current, low voltage limitation, and fast response speed.
