Lightning protection technology of diverter and diverter of external floating roof oil tank 2
2.Lightning protection solutions for external
floating roof oil tanks
In response to the above problems, we have
formulated the following solutions for lightning protection of external
floating roof oil tanks:
2.1 Design Basic
"Technical Specification for Lightning Protection of External Floating Roof Oil Tanks" Part 1: Guidelines Q/SY 1718.1-2014
"Technical Specification for Lightning Protection of External Floating Roof Oil Tanks" Part 2: High and Intermediate Frequency Lightning Current Splitter Q/SY 1718.2-2014
"Technical Specifications for
Lightning Protection of External Floating Roof Tanks" Part 3: Medium and
low frequency lightning current shunt and monitoring system QSY-1718.3-2015
"Lightning Safety Code for Petroleum
and Petroleum Facilities" GB15599-2009
"Industrial Standard for Lightning
Protection of Aboveground Flammable Liquid Storage Tanks" API545-2009
"Installation Standard for Lightning
Protection System" NFPA780-2011
"Measures to prevent ignition of
static electricity, lightning and stray currents" API RP2003
2.2 Lightning protection solution
2.2.1 High and medium frequency lightning current
shunt technology
The high and intermediate frequency
lightning current splitter is a high and intermediate frequency lightning
current discharge device for the floating disk of the outer floating roof oil
tank. The adjustable device solves the difference between the splitter and the
tank wall caused by the slight deformation of the tank body and the
displacement of the floating disk to ensure the floating disk. The high- and
medium-frequency lightning current on the ground is released in time, avoiding
sparks generated during the lightning current release process.
2.2.2 Middle and low frequency lightning current shunt technology
The low- and medium-frequency lightning
current shunt is a low-frequency lightning current discharge device for the
floating plate of the outer floating roof oil tank. The floating plate and the
tank wall are connected through the shunt device to realize the low-impedance
electrical connection between the shunt and the tank wall to ensure the middle
The low-frequency lightning current is released in time, which has the
advantage of low inductance when the lightning current passes, which greatly
reduces the potential of the floating disk, thereby avoiding the phenomenon of
interstitial ignition of the floating disk due to the passage of the lightning
current. The lightning current detection device is added, which can upload the
lightning current data to the monitoring center in real time, realize the
monitoring and statistics of lightning strike data, and realize linkage control
with other systems.
2.2.3 Quantity ratio and installation location
According to the "Technical
Specification for Lightning Protection of External Floating Roof Oil
Tanks": High and medium frequency lightning current splitters "set
one at an interval of no more than 3m along the circumference of the floating
roof."
According to the "Technical
Specification for Lightning Protection of External Floating Roof Oil
Tanks": "A medium and low frequency lightning current shunt should be
installed between the floating roof foam weir plate of the external floating
roof oil tank and the tank wall every 30m. The cross-sectional area of the
shunt line is not less than 50mm2."
Take a storage tank of 20,000 cubic meters
(about 40 meters in diameter and 127 meters in circumference) as an example.
The installation position is based on the escalator in the tank as the starting
point, and 5 diverters are evenly installed along the circumference of the
storage tank at an interval of no more than 30 meters. 45 splitters are
installed evenly distributed at intervals of no more than 3 meters.
