The protection box against lightning really can protect the electrical equipment against transient overvoltages caused by lightning strikes.
Principle of Operation
The principle of operation for the lightning protection box is based mainly on surge protection and grounding technology. In case of lightning striking a power line, the transient voltage instantly increases and makes all the connected equipment on the power grid prone to potential damage.
On the other hand, the SPD acts within 10 nanoseconds and rapidly guides the high voltage instantaneously produced to the grounding system. These currents are discharged to the ground through the low-impedance path created by the grounding system, hence preventing overvoltage from reaching the electrical equipment.
Protection Range and Effectiveness
The application fields for a lightning protection box range from residential and industrial to communication facilities. It reduces the damage resulting from lightning to a great extent.
Residential Electrical Protection: The statistical results of the electrical user survey indicated that after the installation of the lightning protection box, the damage rate of the household equipment in the high-lightning strike area was lowered by more than 80%.
Protection of Industrial Equipment: After a lightning protection box was installed, the damage rate to these pieces of equipment reduced by 90%, thus minimizing the risk of shutdowns or equipment scrapping due to lightning.
Communication Facility Protection: Once a lightning protection box had been fitted, the failure rate in communication equipment was reduced by 85%, which ensured that a signal was transmitted stably.
Installation and Maintenance Requirements
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The resistance of the grounding system shall not be higher than the national standards. Generally, the grounding resistance shall not be higher than 10 ohms.
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If the grounding resistance happens to be above 20 ohms, then the efficiency of discharge by the lightning current is reduced by about 30%, which widens the possibility of the equipment being affected upon the strike of lightning.
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It is recommended to test the protection equipment once a year, especially for those installed in an area where a lightning strike occurs very frequently.
| Item | Grounding Resistance | Maintenance Cycle | Protection Efficiency |
|---|---|---|---|
| Recommended | < 10 ohms | Once a year | 95% |
| Unmaintained | > 20 ohms | No maintenance | < 70% |
Different Application Scenarios
According to various application scenarios, the design and protection capability of a lightning protection box will differ.
The following outlines some major application scenarios and protection effects:
Communication Base Stations: The ultra-short time of overvoltage discharge assures more than a 90% decrease in communication equipment failure.
Power Systems: The installation of lightning protection boxes has reduced equipment failure rates of about 85% in some areas, increasing the stability of the power system manifold.
Protection of Buildings: The lightning protection boxes can be installed in high-rise buildings or commercial establishments to avoid fire breakouts or to avoid damage to any equipment arising due to lightning. After the installation of a lightning protection box, there was a reduction of 70% of lightning accidents in buildings.
