Communication equipment has always been the focus of lightning protection and its problems have always existed.
Due to the massive adoption of high technology advanced equipment in various fields in recent years, coupled with the improvement in the level of operation and maintenance, the operational reliability of communication equipment has also gradually increased, while communication equipment is now more sensitive to lightning, which has led to an increase in lightning accidents. As lightning protection covers a wide range of areas, it must be considered systematically in order to achieve an effective protection effect.
In the face of lightning protection for communications equipment, the use of lightning rods and lightning strips can prevent and reduce the danger to buildings and people. But there is a lot of evidence that, after the installation of these devices such as lightning rods, indoor computer equipment, communications equipment and microelectronic devices in lightning strikes, but still suffer varying degrees of damage, it is not difficult to analyse, causing damage to indoor electronic equipment is the culprit "induction lightning".
According to the survey, accidents caused by induction lightning account for about 80%-90% of lightning accidents. For induction lightning damage path, we can take grounding, shunt voltage equalisation, installation of lightning protection and other methods of protection, to ensure the safety of equipment and personal.
The earthing system is the most important aspect of lightning protection technology. Whether it is direct lightning, induction lightning, or other forms of lightning, the ultimate goal is to send lightning currents to earth. Lightning protection is therefore unreliable without a reasonable and good earthing system. The smaller the grounding resistance, the faster the dispersion of the current, the shorter the high potential holding time of the object struck by lightning, the less dangerous.
For computer sites the grounding resistance is required to be less than or equal to 4 ohms. And take the common grounding method will be lightning grounding, electrical safety grounding, AC ground, DC ground unified as a grounding device. If there are special requirements to set up independent ground, it should be connected between the two ground networks with ground protector, so that the two ground networks are usually independent of each other to prevent interference, when the lightning current comes between the two ground networks through the ground protector instantly connected, forming an equipotential connection.
2、Lightning protection equipotential connections
The purpose of equipotential connections is to reduce the potential difference between the metal parts and systems in the space to be protected against lightning, the metal parts and systems that cross the junction of the lightning protection zones, and the metal parts and systems that reduce the need for protection inside the lightning protection zones, should be made at the junction of the lightning protection zones. Equipotential connections should be made at equipotential connection zones using equipotential connection wires and bolt-fastened wire clips, and, when required, temporary equipotential connections should be made using lightning protectors.
3、Installation of lightning protectors
The "power supply lightning protector" is connected to the power line to contain transient overvoltages and discharge surge currents. From the mains inlet to the end of the power equipment is usually configured into three levels, after the step-by-step voltage limiting and discharge, gradually eliminate lightning energy, to ensure the safety of power equipment, according to the power supply lightning protector classification protection.
"Signal lightning protector" access to the signal interface, on the one hand, can cut off the lightning into the equipment path, on the other hand, can quickly discharge to the earth to ensure the normal work of signal equipment. Signal lightning protector has a variety of specifications, respectively, can be used for telephone, network, analogue communications, digital communications, cable TV and satellite antenna equipment lightning protection of each device input port, especially the introduction of the end, should be installed signal lightning protector.
The lightning protector should be selected to pay attention to the form of interface and grounding reliability, important places should be set up special grounding line, do not lightning protection grounding line and lightning rod grounding line and connected, and as far away as possible, separate into the ground. Only by taking adequate lightning protection measures and correctly selecting and installing lightning protectors can the safety of communication equipment be truly protected.