# Lightning Protection and Grounding of a Solar Power Plant in the Krasnodar Kray

The ZANDZ Technical Center has received a request to calculate the lightning protection system for a solar power plant. Let us further consider a solution proposed by our specialists.

Initial data:

• facility: solar power plant;

• dimensions: 120 m x 102 m x 2 m;

• Soil resistivity: 100 Ohm*m.

• calculate the lightning protection system;

• calculate the grounding device.

Solution:

Lightning protection and grounding of the building are made in accordance with:

The facility is classified as “conventional” from the viewpoint of SO and as Category III of the lightning protection according to RD.

A set of measures to provide necessary requirements to the lightning protection system and to the grounding arrangement for the solar power plant includes the following solutions:

1. 10 m lightning arresters located along the perimeter of the protected area are used as lightning arresters to protect the area.

2. Copper-plated steel electrodes 3 m long are used as a vertical grounding arrangement.

3. The copper-plated steel strip with a cross-section of 30 x 4 mm, combining all vertical electrodes, is used as a horizontal ground electrode. The distance to the mast foundation is at least 1 m. Strip deepening is 0.5 to 0.7 m.

4. Connection to the grounding arrangement is made through clamps ZZ-005-064.

The results of calculation of protection zones according to SO:

h = 10 m;

Cone height according to SO, Table 3.4:

h0 = 0,85*h = 8,5 m;

Cone radius according to SO, Table 3.4:

r0 = 1,2*h = 12 m;

For the protection zone with the required reliability, radius rx at the height of h0 = 2 m is defined as:

М - m

Distance between the lightning arresters (maximum):

L = 38 m;

Limit distance between lightning arresters according to SO, Table 3.6:

Sagging height:

For the protection zone with the required reliability, radius rcx at height h0 = 2 m is defined as follows:

Ground terminal resistance calculation:

Vertical electrode resistance:

Ом - Ohm
Верт - Vert
Экв - Eq

where    ρρeq is equivalent soil resistivity, 100 Ohm·m;

L – is vertical electrode length, 3 m;

d – is vertical electrode diameter, 0.014 m;

T – deepening - is the distance from the ground surface to the ground electrode, 2 m;

where     t  – is deepening of the top of the electrode, 0.5 m.

Horizontal electrode resistance:

Ом - Ohm
Гор - Hor

where    ρ – is soil resistivity, 100 Ohm·m;

b - is horizontal electrode width, 0.03 m;

h - is horizontal electrode depth, 0.7 m;

Lhor - is horizontal electrode length, 1,160 m.

Electrical impedance of the grounding arrangement:

Ом - Ohm
ЗУ - GA

where n – is a number of sets, vertical grounding arrangements - 11 pcs, horizontal grounding arrangement - 1 pc;

Kutil is utilization rate, 0.63.

The calculated resistance of the grounding arrangement is 0,38 Ohm.

The location of the equipment is shown in Figure 1

.

Условные обозначения - Legend
- молниеприемник-мачта высотой 10 м - 10 m lightning rod
- полоса стальная оцинкованная сечением 30х4 мм - steel zinc-plated bar with cross-section 30 x 4 mm
- зажим для подключения проводника - clamp for connecting conductor
- вертикальный заземлитель длиной 3 м - 3 m vertical grounding electrode
- зона защиты на высоте 2 м - protection zone at the height 2 m

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 LIGHTNING PROTECTION: 1. ZZ-201-010 ZANDZ 10 m vertical lightning arrester (zinc-plated steel; with parts embedded under the foundation) 1 GROUNDING ARRANGEMENT: 2. GL-11075-50 GALMAR Copper-plated strip (30 * 4 mm / S 120 mm²; 50-meter strip bundle) 26 0,98 Вес за метр 3. ZZ-001-065 ZANDZ Copper-plated threaded grounding rod (D14; 1,5 m) 22 2,00 4. ZZ-002-061 ZANDZ Threaded coupling 12 0,08 5. ZZ-003-061 ZANDZ Termination 11 0,07 6. ZZ-004-060 ZANDZ Guide head for jackhammer attachment 5 0,09 7. ZZ-005-064 ZANDZ Conductor connection terminal (up to 40 mm) 106 0,312 8. ZZ-006-000 ZANDZ Conductive grease 2 0,10 9. ZZ-007-030 ZANDZ Waterproofing tape 36 0,40 10. ZZ-008-000 ZANDZ Attachment to the hammer (SDS max) 1 0,50

Do you have any questions regarding lightning protection and grounding of the solar power plant? Please contact the ZANDZ Technical Center.

Related Articles: