​Installation method and installation precautions of power surge arrester

Installation method of power surge arrester
1. Install the power lightning arrester in parallel. The installation position of the charcoal machine is the rear end of the switchboard or the knife switch (circuit breaker) in the classroom of the satellite teaching viewing point. Use four sets of M8 plastic expansion and matching self-tapping screws. on the wall.
2. The installation size (70×180) and the corresponding installation holes on the power arrester should be drilled on the wall.
3. Connect the power supply. The live wire of the power arrester is red, the neutral wire is blue, and the cross-sectional area is BVR6mm2. Multi-strand copper wire, the ground wire of the charcoal machine is yellow and green, and the cross-sectional area is BVR10m m2. Stranded copper wire, the wiring length is less than or equal to 500mm. If the limit is less than or equal to 500mm, it can be extended appropriately, but the principle of keeping the wiring as short as possible should be followed, and the corner should be greater than 90 degrees (arc rather than right).
4. Connect the power supply to the lightning conductor. One end of the power arrester cable is directly and firmly crimped to the terminal of the power arrester. The grounding wire is connected to the independent grounding grid or the three-phase power supply grounding wire provided by the school.

Precautions for installation of power surge arrester
1. Wiring direction
When the lightning arrester is installed, the input and output terminals must not be reversely connected, otherwise, the lightning protection effect will be seriously affected, and even the normal operation of the equipment will be affected. The input end of the lightning arrester is relative to the propagation direction of the lightning wave, that is, the input end of the feeder, and the output end is to protect the equipment.
2. Connection method
There are two kinds of wiring methods: series connection and parallel connection. Generally, only the terminal connection method is used in series connection method, and the other connection method is used in parallel connection method. The neutral wire of the power cable is connected to the “N” wiring hole of the power SPD, and finally the ground wire drawn from the “PE” wiring hole of the power SPD is connected to the lightning protection grounding busbar or the lightning protection grounding bar. In addition, the minimum cross-sectional area of the connecting wire of the lightning arrester should comply with the relevant provisions of the national lightning protection project.

3. Ground wire connection
The grounding length of the grounding wire should be as short as possible, one end should be directly crimped to the terminal of the lightning arrester, and the grounding wire should be connected to an independent grounding network (isolated from the electrical grounding) or connected to the grounding wire in the three-phase power supply.
4. Installation location
The power supply lightning arrester generally adopts a graded protection method. Install a primary power supply lightning protection device at the main power distribution cabinet of the building. Secondly, install a secondary power supply lightning protection device at the sub-power supply of the building where the electronic equipment is located. At the front of important electronic equipment, install three-level power lightning arrester, and at the same time, ensure that there are no inflammable and explosive materials near the installation to prevent fire caused by electrical sparks.
5. Power off operation
During installation, the power supply must be disconnected, and live operation is strictly prohibited. Before operation, a multimeter must be used to test whether the busbars or terminals of each section are completely powered off.
6. Check the wiring
Check whether the wiring is in contact with each other. If there is contact, deal with it immediately to avoid short circuit of equipment. After the installation of the lightning arrester is completed, it should be checked regularly to check whether the connection is loose. If it is found that the lightning protection device is not working properly or damaged, the lightning protection effect of the lightning protection device will deteriorate, and it needs to be replaced immediately.

Common parameters of power lightning arrester
1. Nominal voltage Un:
The rated voltage of the protected system corresponds. In the information technology system, this parameter indicates the type of protector that should be selected. It indicates the rms value of the AC or DC voltage.
2. Rated voltage Uc:
It can be applied to the designated end of the protector for a long time without causing changes in the characteristics of the protector and activating the maximum RMS voltage of the protection element.
3. Rated discharge current Isn:
When a standard lightning wave with a waveform of 8/20μs is applied to the protector for 10 times, the maximum surge current peak value that the protector can withstand.
4. Maximum discharge current Imax:
When a standard lightning wave with a waveform of 8/20μs is applied to the protector once, the maximum surge current peak value that the protector can withstand.
5. Voltage protection level Up:
The maximum value of the protector in the following tests: the flashover voltage with a slope of 1KV/μs; the residual voltage of the rated discharge current.
6. Response time tA:
The action sensitivity and breakdown time of the special protection element mainly reflected in the protector vary within a certain period of time depending on the slope of du/dt or di/dt.
7. Data transmission rate Vs:
Indicates how many bits are transmitted in one second, unit: bps; it is the reference value for the correct selection of lightning protection devices in the data transmission system. The data transmission rate of lightning protection devices depends on the transmission mode of the system.
8. Insertion loss Ae:
The ratio of voltages before and after protector insertion at a given frequency.
9. Return loss Ar:
It represents the proportion of the front wave reflected at the protection device (reflection point), and is a parameter that directly measures whether the protection device is compatible with the system impedance.
10. Maximum longitudinal discharge current:
Refers to the maximum impulse current peak value that the protector can withstand when a standard lightning wave with a waveform of 8/20μs is applied to the ground once.
11. Maximum lateral discharge current:
When a standard lightning wave with a waveform of 8/20μs is applied between the finger line and the line, the maximum surge current peak value that the protector can withstand.
12. Online impedance:
Refers to the sum of the loop impedance and inductive reactance flowing through the protector at the nominal voltage Un. Often referred to as “system impedance”.
13. Peak discharge current:
There are two types: rated discharge current Isn and maximum discharge current Imax.
14. Leakage current:
Refers to the DC current flowing through the protector at a nominal voltage Un of 75 or 80.

 


Post time: Aug-26-2022