A meteorological station is a set of various instruments designed for meteorology measurements (weather observations). They can be installed at the locations convenient for the user since they are much more compact than in past. The ZANDZ Technical Center has received a request to calculate the lightning protection for a meteorological station located in a transformer substation. Unusual solution but there are no special requirements to the facility's lightning protection. Let us continue with more detailed review of our offered solution.
Calculation of lightning protection for the meteorological station in the transformer substation
Facility: meteorological station in the transformer substation
Figure 1. Facility plan.
Task: To perform calculations of the lightning protection system for the meteorological station located in the transformer station
Solutions to meet the requirements to the lightning protection system of the meteorological station in the transformer substation:
- The lightning protection is made in accordance with the Electrical Installations Code (EIC), Rev. 7, SO 153-34.21.122-2003 Guidelines for Lightning Protection of Buildings, Structures, and Industrial Utilities (hereinafter referred to as SO) and RD 34.21.122-87 Guidelines for Lightning Protection of Buildings and Structures (hereinafter referred to as RD).
- The facility belongs to Class III according to RD. The system reliability shall be at least 0.9.
- Lightning protection of the facility is made using a 10 m lightning rod.
- For the lighting arrester, a grounding arrangement is installed as follows:
- Laying the horizontal grounding device for the current flowing in two directions. Length of each ground electrode is 5 m. The ground electrode is made of a corrosion-resistant steel copper-plated strip with a cross-section of 4 x 30 mm (GL-11075), the laying depth is 0.5 m.
- At the end of the horizontal ground electrode, one vertical electrode with the length of 3 m is installed in each direction.
- Vertical and horizontal electrodes, as well as horizontal electrodes with the interception rod are connected using clamps ZZ-005-064.
Results of the calculation performed using the software developed by the Krzhizhanovsky Energy Institute (OAO ENIN):
density of lightning strikes into the ground is 4 strikes/sq. km per year.
Total number of strikes into the system is 0.013 (once per 77 years).
The total number of breakouts into the system is 0.001 (once every 1000 years).
The probability of a blowout into the system's facilities is 0.079.
The system reliability is 0,921.
Figure 2 shows hardware layout.
Table 1 includes the list of required hardware and materials.
Условные обозначения: - Legend:
- молниеприемник-мачта высотой 10 м - 10 m lightning rod
- полоса стальная омедненная сечением 30 х 4 мм - steel copper-plated strip, 30 x 4 mm
- зажим для подключения проводника - clamp for connecting conductor
- вертикальный заземлитель длиной 3 м - 3 m vertical grounding electrode
Figure 2. Hardware layout for the lightning protection of the meteorological station in the transformer substation
Table 1. List of material requirements.
Do you have any questions about lightning protection of meteorological stations or other facilities? Please, contact the ZANDZ Technical Center!