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Working principle of the gripper
When a lightning is approaching to the earth, a corona discharge is going to be created on the lightning conductor. In case of a classic lightning rod, this upward corona discharge starts its propagation in direction of an upward main branch after a long period of its transient phase. An initialization advancing time of the WAT Franklinplus gripper allow to shorten time necessary for formation and continuous propagation of the upward discharge which is connected with higher efficiency of lightning trapping in reference to the classic lightning rod.
Thanks to its initialization advancing time, the WAT Franklinplus gripper radiates a high-voltage signal of the exact determined and controlled frequency and amplitude. Its efficiency is secured by the rapid formation and propagation of the upward main branch under space charge reducing around its tip.
The WAT Franklinplus gripper is self-sustaining. Its energy is obtained from a surrounding electrical field which is presenting during a storm ((10 to 20 kV / m). The initialization advancing time shall be trigged as soon as the surrounding electrical field exceeds its peak effective value which corresponds with minimal thunder-stroke risks.
Functions of the WAT Franklinplus tip are following:
- it emits the corona discharge consisting of high-voltage impulses
- it entraps the lightning and leads it to the earth
The energy necessary for charging of electric equipments situated inside the gripper is being "sucked" by means of a metal jacket of the gripper cylinder. The metal cylinder contains electronic equipment of the system which generates corona discharges by means of a pair of auxiliary control electrodes. A rod at the lower gripper end is provided with thread M20 intended for connection of the gripper with basic rods.
By means of the WAT Franklinplus gripper testing at independent high-voltage laboratories it has been proved that the active lightning conductor efficiency is in accordance with standard STN 341391 or NF C 17-102. Issued certificates confirm these facts.
Basis parameters of the WAT Franklinplus grippers
| ΔT [µs] | Typ | Cylinder diameter / Total gripper length [mm] | Weight [kg] |
|---|---|---|---|
| 15 | WAT Franklinplus 421H | Ø70 / 330 | 1,65 |
| 20 | WAT Franklinplus 421 | Ø70 / 330 | 1,65 |
| 30 | WAT Franklinplus 422 | Ø70 / 330 | 1,65 |
| 45 | WAT Franklinplus 423 | Ø70 / 330 | 1,65 |
| 60 | WAT Franklinplus 425 | Ø70 / 330 | 1,65 |
Notice: The system correct function depend especially on a right project, material used and full observance both installation instructions and particular standards.
Mathematics and physics description
of the WAT Franklinplus gripper
During a storm in the open air under fulfillment of given space conditions, the WAT-Franklinlplus gripper shall radiate an upward signal as the first. The time obtained in this way compared with the classic lightning rod under the same conditions is called an initialization advancing time gain ∆T. A gain or loss of the initialization advancing time is determined directly from laboratory test results.
Protected zones (see the table) with following item meanings:
Rp: It is a radius of protection coverage on horizontal level situated in vertical distance h from the gripper tip [m]
h: It is a gripper tip height above a protected structure (protected structures) [m]
D: It is an impact distance with following values:
20 m for rate of protection LPS I
30 m for rate of protection LPS II
45 m for rate of protection LPS III
60 m for rate of protection LPS IV
∆L = 1 E6 . ∆T (initialization advancing time) [m]
Rp = √ h (2D + h) + ∆L (2D + ∆L) (pro h >= 5 m)
For h « 5 m it shall be necessary to use the table of radii of protection from the STN 34 1391 standard and from the Z3 (05/2008) revision.
Radius of protection of the WAT Franklinplus grippers
| Protection level LPL = I (D = 20 m) | |||||
|---|---|---|---|---|---|
| WAT Franklinplus | 421H | 421 | 422 | 423 | 425 |
| ΔT [µs] | 15 | 20 | 30 | 45 | 60 |
| h [m] | Rp [m] | ||||
| 2 | 13 | 14 | 19 | 25 | 31 |
| 3 | 19 | 22 | 28 | 37 | 47 |
| 4 | 25 | 29 | 38 | 50 | 62 |
| 5 | 32 | 37 | 47 | 63 | 78 |
| 20 max | 35 | 40 | 50 | 65 | 80 |
| Protection level LPL = II (D = 30 m) | |||||
|---|---|---|---|---|---|
| WAT Franklinplus | 421H | 421 | 422 | 423 | 425 |
| ΔT [µs] | 15 | 20 | 30 | 45 | 60 |
| h [m] | Rp [m] | ||||
| 2 | 15 | 17 | 22 | 28 | 35 |
| 3 | 23 | 28 | 33 | 43 | 51 |
| 4 | 30 | 35 | 43 | 57 | 69 |
| 5 | 37 | 43 | 55 | 71 | 85 |
| 20 | 44 | 49 | 59 | 74 | 89 |
| 30 max | 45 | 50 | 60 | 75 | 90 |
| Protection level LPL = III (D = 45 m) | |||||
|---|---|---|---|---|---|
| WAT Franklinplus | 421H | 421 | 422 | 423 | 425 |
| ΔT [µs] | 15 | 20 | 30 | 45 | 60 |
| h [m] | Rp [m] | ||||
| 2 | 18 | 20 | 25 | 32 | 38 |
| 3 | 27 | 30 | 38 | 48 | 58 |
| 4 | 36 | 48 | 50 | 64 | 77 |
| 5 | 45 | 51 | 63 | 80 | 97 |
| 20 | 55 | 60 | 70 | 86 | 101 |
| 45 max | 60 | 65 | 75 | 90 | 105 |
| Protection level LPL = IV (D = 60 m) | |||||
|---|---|---|---|---|---|
| WAT Franklinplus | 421H | 421 | 422 | 423 | 425 |
| ΔT [µs] | 15 | 20 | 30 | 45 | 60 |
| h [m] | Rp [m] | ||||
| 2 | 20 | 23 | 28 | 35 | 42 |
| 3 | 31 | 34 | 42 | 53 | 63 |
| 4 | 41 | 46 | 56 | 71 | 85 |
| 5 | 51 | 58 | 71 | 89 | 106 |
| 20 | 63 | 69 | 80 | 97 | 113 |
| 60 max | 75 | 80 | 90 | 105 | 120 |
Working principle of the gripper
When a lightning is approaching to the earth, a corona discharge is going to be created on the lightning conductor. In case of a classic lightning rod, this upward corona discharge starts its propagation in direction of an upward main branch after a long period of its transient phase. An initialization advancing time of the WAT Franklinplus gripper allow to shorten time necessary for formation and continuous propagation of the upward discharge which is connected with higher efficiency of lightning trapping in reference to the classic lightning rod.
By means of the WAT Franklinplus gripper testing at independent high-voltage laboratories it has been proved that the active lightning conductor efficiency is in accordance with standard STN 341391 or NF C 17-102. Issued certificates confirm these facts.
Currently, the only documented installation in the world more than 5 million units (2009).
Protected zones
Rp: It is a radius of protection coverage on horizontal level situated in vertical distance h from the gripper tip [m]
h: It is a gripper tip height above a protected structure (protected structures) [m]
Select your made-to-measure-solution
Price analysis of type structure lightning protections, purchase cost comparison in reference to the classic lightning rod and the active WAT Franklinplus lightning conductor. Select a suitable structure type and click to display details.
