Green lightning protection is intended to provide facility isolation from direct lightning strike and it ensures full protection with a 99.87% reliability. The Green lightning protection devices differ from the conventional (or active) lightning arresters in their operating principles: isolation of the facility from the lightning rather than catching the lightning.
Recently, ZANDZ Technical Centre has received a task to calculate the Green lightning protection for a chimney. This facility does not require such lightning protection type, but the customer insisted on this approach. Let us consider the solution we provided below.
Calculation Example of the Green lightning protection for a chimney
Facility: a 70 m high chimney.
Task: to perform calculations for a Green lightning protection system for the chimney.
Solutions to meet the requirements to the Green lightning protection system for the chimney:
1. The chimney may be protected from lightning by installing a trapezoid Green lightning protection system. The Green lightning protection will be attached to the chimney top in the form of three panels stretched between the existing guide ropes as it is shown in Fig. 1. The existing lightning rod at the chimney top should be removed.
2. Each panel of the proposed trapezoid Green lightning protection system will be 15.24 meters long and will have 11 strings of a dissipating wire.
3. In addition, due to the fact that the chimney is high, three spherical ionizers placed on curved rods spaced at 120 degrees to provide additional dissipating capability should be installed at the half of the height. In total, three elements of the trapezoid Green lightning protection and three spherical ionizers provide more than 10,260 dissipating points to prevent lightning strike to the chimney.
4. Conventional lightning rod is developed so that to generate a strong upward streamer and take the lightning strike by this. The Green lightning protection operates in an opposite way. The Green lightning protection is a system preventing the lightning strike. It operates due to the dissipation of the charge accumulated at the structure during a storm. Due to the charge dissipation, opposite streamers are not formed, and as a result, the lightning strike is prevented.
5. To provide functioning of the Green lightning protection, a grounding device with a low resistance of 5 Ohm is required. If a chimney has a good existing grounding system, and its structure is electrically continuous along all the height, additional grounding is not required.
6. The Green lightning protection may be installed within two days by three installing technicians. For installation, it is necessary to provide ability of using a winch for lifting the Green lightning protection up to the chimney. The Green lightning protection is supplied with a "strike-free" guarantee under the condition that it is installed under the supervision of the installation technician for Green lightning protection.
Figure 1 shows hardware layout.
Table 1 includes the list of required hardware and materials.
Figure 1. Hardware layout for the Green lightning protection for the chimney
Table 1. List of required materials.
|Trapezoid Green lightning protection|
|1.||A panel with a dissipating wire, 15.24 m, 11 strings||3|
|2.||Guide ropes for the Green lightning protection, m (approximately)||490|
|3.||A spherical ionizer||3|
|4.||A curved rod and a mounting bracket for a spherical ionizer||3|
Do you have any questions about lightning protection for the chimney or other facilities? Please, contact ZANDZ Technical Center!