The necessity of anti-lightning, anti-static and anti-surge in petrochemical enterprises

With the progress of society and the development of high-tech, various information equipment, precision instruments, electronic computers and data network equipment have been more and more widely used in petrochemical enterprises. The lightning protection for these devices will also become the focus of protection for petrochemical companies. On the one hand, the application of these equipment in the petrochemical industry has greatly promoted the modernization process and promoted the development of the petrochemical industry. On the other hand, the electronic equipment used in the petrochemical industry has poor overvoltage tolerance and low insulation strength. Electronic equipment is very susceptible to lightning. As the petrochemical industry suffers from lightning incidents every year, the destructive power is huge, and the petrochemical industry is more flammable, explosive and easy to spread. Once lightning strikes, the danger can be imagined. In order to avoid interruption of the operation of electronic equipment caused by lightning strikes, and even permanent damage, it is particularly important to increase lightning protection for petrochemical industries.

The harm of lightning to the petrochemical industry

The lightning current generated during the lightning strike will produce extremely high thermal effects, which can easily cause the metal wires to vaporize or melt, forming a short circuit in the power system, and then causing fire or explosion;

The lightning current also induces an alternating magnetic field around the lightning strike point, thereby inducing an induced current on the line, causing local overheating of electrical equipment or forming a spark discharge and causing a fire；

Lightning strikes will induce a large amount of electric charges that are opposite to the nature of lightning in the struck metal equipment, which can easily cause spark discharge and cause hidden dangers;

Electromagnetic radiation formed by lightning current or discharge between cumulonimbus clouds will interfere with or destroy the circuits and electronic equipment of the control system in the petrochemical control room through coupling;

Lightning protection, anti-static and anti-surge measures for petrochemical industry:

(1) Lightning

Use elevated grounded metal conductors, such as lightning rods and lightning protection strips, to install on the top and side of the building to prevent the building from being damaged by direct lightning.

(2) Diversion

After the lightning interception (lightning) by the air-termination device, the lightning current from the air-termination is divided into multiple channels to guide and leak into the earth, so that the lightning current of each branch reduces the induced voltage or current on the nearby conductors, wires, and cables.

(3) Voltage equalization (equipotential connection)

Connect nearby metal conductors with conductors and ground them to make the voltages equal to each other to prevent mutual lightning and counter-strike sparks, prevent maintenance operators from contacting adjacent conductors to cause electric shock, and protect personal equipment.

(4) Grounding

Grounding is an important part of lightning protection. It includes the grounding electrode, the connection between the grounding electrode, the grounding strap and the grounding lead of each grounding device, etc. From the perspective of lightning protection and safety, the lower the grounding resistance of the grounding system, the better, but the too low grounding resistance will consume A lot of human and financial resources. Generally, the grounding resistance value is not more than 10 ohms.

(5) Electromagnetic blockade

In order to prevent the transmission of power surges from AC power supply lines and information system network transmission lines, damaging equipment and endangering personnel safety, for external transmission lines and cables, closed metal trunking or laying through metal pipes should be used, and for metal trunking, The threaded metal pipeline shall be grounded reliably and appropriately at multiple points to minimize the equipment damage caused by the surge caused by the induced lightning.

(6) Reasonable wiring

When the lightning current from the flashover leaks into the ground along the shunt, the electromagnetic coupling will induce voltage or current on nearby conductors (wires, cables). Referred to as surge. In order to reduce the power surge on the wires and cables, when arranging the power lines and signal lines, try to stay away from the lightning protection down conductor.

Notice: The “Retractable Grounding Reel” (RGR for short) is designed to discharge the static electricity of floating roof storage tanks. It is used as the equipotential bonding between the floating roof and tank shell. The lightning current and bound charge will be effectively and rapidly dissipated to the earth upon a lightning strike. Compared with the conventional bypass conductor, it will effectively decrease the possibility of a lightning-induced fire, and make it more reliable and safe.