To provide safe flight of an aircraft, it is necessary to ensure an uninterrupted functioning of communication systems and also meteorological conditions tracking system. One of obligatory conditions is grounding of these systems' equipment.
Our ZANDZ Technical Center received a request for a calculation of functional grounding for a helicopter deck, in particular for operation of radio equipment and meteorological sensors.
Initial data for calculation
- soil - clay, clay loam;
- soil resistivity for the calculation - 100 Ohm * m.
Task:
Calculate grounding device with the resistance of not more than 4 Ohm.
The set of measures on the provision of the necessary requirements to the grounding device is presented by the following solutions:
- installation of 5 vertical electrodes 6 m long, united by a horizontal electrode of stainless steel copper-bonded corrosion-resistant tape with the cross-section of 30x4 mm. Deepening 0,5 - 0,7 m. The distance between the ground electrodes - not more than 6 m.
Grounding device resistance calculation:
Vertical electrode resistance:
where ρэкв - equivalent soil resistivity - 100 Ohm*m;
L – vertical electrode length - 6 m;
d – vertical electrode diameter - 0.014 m;
T – deepening - the distance from the ground surface to the ground electrode system 3.5 m;
where t is the deepening of the electrode top - 0,5 m
Horizontal electrode resistance:
where ρ - equivalent soil resistivity - 100 Ohm*m;
b - horizontal electrode width - 0.03 м;
h - horizontal electrode laying depth -0.5 m;
Lrop - horizontal electrode length - 24 m.
Impedance of the grounding device:
where n-number of kits, vertical ground electrodes -5 pc., horizontal ground electrode - 1 pc.;
Kисп - utilization ratio, 0.69;
The design resistance of the grounding device is 3,67 Ohm ohms, which is less than the required value of 4 ohms.
Location of equipment is shown in figure 1.
Figure 1 - Location of equipment.
| электрод L=6 m, D=14 mm | Electrode L=6 m, D=14 mm |
| полоса омедненная сечением 30*4 mm (GL-11075) | copper bonded tape with the cross section of 30* 4 mm (GL-11075) |
Перечень необходимых материалов приведен в таблице 1.
The list of required material is given in Table 1.
| № | Figure | Product item | Name | Quantity, pcs. |
| 1. |  |
ZZ-001-065 | ZANDZ Copper-coated threaded grounding rod (D14; 1.5 m) | 20 |
| 2. |  |
ZZ-002-061 | ZANDZ Threaded coupler | 16 |
| 3. |  |
ZZ-003-061 | ZANDZ Starting tip | 5 |
| 4. |  |
ZZ-004-060 | ZANDZ Driving head for a jackhammer | 4 |
| 5. |  |
ZZ-005-064 | ZANDZ Clamp for connecting conductor (up to 40 mm) | 9 |
| 6. |  |
ZZ-006-000 | ZANDZ Conductive grease | 2 |
| 7. |  |
ZZ-007-030 | ZANDZ Waterproof tape | 3 |
| 8. |  |
ZZ-008-000 | ZANDZ Header for a jackhammer (SDS max) | 1 |
| 9. |  |
GL-11075-10 | GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 10 meters) | 3 |
| 10. |  |
GL-11751A | GALMAR Clamp to the facade / wall for a flat down conductor (down conductor 30 * 4mm; galvanized steel with painting) | 2 |
Do you have any questions on grounding of a helicopter deck? Please contact our ZANDZ Technical center!
See also:
- Grounding resistance measuring with classical methods
- Why long vertical ground electrodes are required?
- How to calculate technological grounding real example