The resistance of the grounding arrangement for the supports for power lines over 1 kV are determined in the EIC, item 2.5.75, or in GOST R 58882-2020, item 7.5.1; there are some differences, though.
According to the EIC, for power line supports 3-20 kV located in the populated area with soil resistivity ρ up to 100 Ohm*m, the resistance of the grounding arrangement should not exceed 30 Ohm, while in soils having soil resistivity above 100 Ohm*m, it should not exceed 0.3*ρ Ohm. In other cases, the rated resistance is determined as follows:
| Equivalent soil resistivity, Ohm·m | Maximum grounding arrangement resistance, Ohm |
| Up to 100 | 10 |
| 100 to 500 | 15 |
| 500 to 1,000 | 20 |
| 1,000 to 5,000 | 30 |
| Over 5,000 | 6-10 |
Table 2.5.19 of the EIC. Maximum resistance of grounding arrangements for the supports of power lines
This table is also provided in GOST R 58882-2020. GOST R 58882-2020, item 7.5.1.4, states that for 110 kV power line supports, the resistance of the grounding arrangement should not exceed 6 Ohm, and for 220 kV power lines, it is 10 Ohm.
For all double-circuit or multi-circuit power line supports, irrespective of their voltage, the resistance of the grounding arrangement should be twice lower than stated in table (item 7.5.1.3), like for any support higher than 50 m (item 7.5.1.1).
If you have any questions for lightning protection and grounding of the power line supports, contact the ZANDZ Technical Center.
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