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To protect the device, you need to evaluate its environment, the lighting affection degree objectively.
Because surge has close relationship with the voltage amplitude, frequency, network structure, device
voltage-resistance, protection level, ground and etc. The thunder proof work shall be a systematic project,
emphasizing the all-round protection (including building, transmission cable, device, ground and etc.).
There shall be comprehensive management and the measures shall be scientific, reliable, practical and
economic. Considering the high voltage during the inductive thundering, the International Electrotechnical
Committee (IEC) standard on the energy absorbing step by step theory and magnitude classification in the
protection zone, you need to prepare multiple precaution levels.
You can use the lightning rod, lightning strap or the lightning net to reduce the damage to the building,
personal injury or the property,
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The lightning protection device can be divided into three types : Power lightning arrester: There are
220V single-phrase lightning arrester and 380V three-phrase lightening arrester (mainly in parallel
connection, sometimes use series connection ) You can parallel connect the power lightning arrester
in the electric cable to reduce the short-time voltage change and release the surge current. From the
BUS to the device, there are usually three levels so that system can reduce the voltage and release
the current step by step to remove the thunderstorm energy and guarantee the device safety. You
can select the replaceable module type, the terminal connection type and portable socket according
to your requirement.
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Signal lightning arrester: This device is mainly used in the PC network, communication system. The
connection type is serial connection. Once you connected the signal lightning arrestor with the signal
port, it can cut the channel of the thunderstorm to the device, and on the other hand, it can
discharge the current to the ground to guarantee the device proper work. The signal lightning
arrester has many specifications, and widely used in many devices such as telephone, network,
analog communication, digital communication, cable TV and satellite antenna. For all the input port,
especially those from the outdoor, you need to install the signal lightning arrester.
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Antenna feed cable lightning arrester: It is suitable for antenna system of the transmitter or the
device system to receive the wireless signal. It uses the serial connection too.
Please note, when you select the lighting arrester, please pay attention to the port type and the earthing
reliability. In some important environment, you need to use special shielded cable. Do not parallel
connect the thunder proof ground cable with the ground cable of the lightning rod. Please make sure they
are far enough and grounded respectively.
2. The earthing modes
We all know the earthing is the most complicated technology in the electromagnetism compatibility
design since there is no systematic theory or module. The earthing has many modes, but the selection
depends on the system structure and performance. The following are some successfully experience from
our past work.
One-point ground: In the following figure you can see there is a one-point ground. This connection
provides common port to allow signal to be transmitted in many circuits. If there is no common port, the
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