The ZANDZ Technical Centre has received a request to calculate lightning protection and grounding arrangement for the tank farm located in Dikson. Let's consider what solution was provided.
facility: tank farm located in Dikson;
soil resistivity 1000 Ohm*m.
To calculate the lightning protection system and a grounding arrangement.
The activities have been performed according to:
- EIC, Rev. 7. Electrical Installations Code (hereinafter referred to as the EIC);
- SO 153-34.21.122-2003 Instructions for Mounting Lightning Protection for Buildings, Structures, and Industrial Utilities (hereinafter referred to as SO);
- RD 34.21.122-87 Instructions for Mounting Lightning Protection for Buildings and Structures (hereinafter referred to as RD).
The facility is classified as Category 2 according to RD.
A set of measures to meet the necessary requirements to the lightning protection system and grounding arrangement for the tank farm includes the following solutions:
1. 16 m standalone lightning rods are used as lightning arresters.
2. Reservoir bodies are connected to the grounding arrangement in at least 2 points.
3. Electrolytic grounding sets ZZ-100-102 are used as grounding arrangements, and the distance between electrodes and from the electrodes to the foundations/piles of the facility is at least 3 m.
4. A steel copper-plated bar with cross-section 30 x 4 mm is used as a horizontal grounding arrangement combining all electrodes. Bar deepening is 0.5 to 0.7 m.
5. The grounding arrangement is connected using clamps ZZ-005-064.
Ground terminal resistance calculation:
Resistance of the electrolytic grounding set ZZ-100-102 is:
Ом - Ohm
where С is a dimensionless factor describing the electrolyte concentration in the surrounding soil, 0.125;
ρ – is soil equivalent resistivity, 1,000 Ohms m;
L is vertical electrode length, 2.4 m;
d is vertical electrode diameter, 0.065 m;
T deepening; is the distance from the ground surface to the ground electrode, 0.6 m;
Horizontal electrode resistance:
Гор - Hor
Ом - Ohm
where ρ – is soil resistivity, 1,000 Ohm·m;
b - is horizontal electrode width, 0.03 m;
h - is horizontal electrode depth, 0.5 m;
Lhor is horizontal electrode length, 170 m.
Electrical impedance of the grounding arrangement:
ЗУ - GA
Ом - Ohm
where n – is a number of sets, vertical grounding arrangements - 4 pcs, horizontal grounding arrangement - 1 pc;
Kutil – is utilization ratio, sets ZZ-100-102 - 0.99; horizontal grounding arrangement - 0.7.
The calculated resistance of the grounding arrangement is 6,9 Ohm.
The layout of the equipment is shown in Figure 1.
Условные обозначения: - Legend:
- молниеприемник-мачта высотой 16 м - lightning rod 16 m high
- полоса стальная оцинкованная сечением 30х4 мм - steel zinc-plated bar, cross-section 30 x 4 mm
- зажим для подключения проводника - conductor connecting clamp
- комплект электролитического заземления zz-100-102 - zz-100-102 electrolytic grounding set
- зона R = 5 м, H = 2,5 м над дыхательными клапанами, подлежащая защите - protected zone R = 5 m, H = 2.5 m over breathing valves
- зона защиты на высоте 1 м для II категории - protection zone at the height 1 m for category II
Figure 1. Equipment layout.
The list of necessary materials is given in Table 1.
Table 1. List of needed materials.
|№||Part number||Name||Quantity, pcs.||Unit weight, kg||Note|
|1.||ZZ-201-016-В7-Сн7-С10||ZANDZ 16 m vertical lightning arrester (zinc-plated steel; with parts embedded under the foundation)||4||Ветровой р-н – 7; снеговой – 7; сейсмичность - 10|
|2.||ZZ-100-102||ZANDZ Electrolytic Grounding Set (horizontal; 3 meters length)||4||95|
|3.||ZZ-005-064||ZANDZ Conductor connection terminal (up to 40 mm)||31||0,312|
|4.||ZZ-007-030||ZANDZ Waterproofing tape||6||0,40|
|5.||GL-11075-50||GALMAR Copper-clad strip (30*4 mm / S 120 mm²; 50-meter strip bundle)||5||0,98||Вес 1 м|
Do you have any questions regarding lightning protection and grounding for a tank farm? Please contact the ZANDZ Technical Center!