Lightning protection


Maximum operating voltage24 kV
Protection typeAgainst indirect lightning
Protection for line, MOA
Installation1 product per pole
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Preview     20
Preview     20 sm
Preview     20

he SAi20z is intended for ensuring protection of Conductors and Insulators against indirect lightning strikes, installed on Section- and Termination Poles.

The SAi20z installed in association with Metal-Oxide-Arrester provides the best possible protection for distribution substations against lighting activity.

Operational Principle

The Operational Principle is based on the EasyQuench Technology.

Using the resistance of the ground between two poles, only one device needs to be installed per Pole.

This advantage makes to SAi20z a very cost effective solution to protect against more than 80% of the lightning issues.

Medium sai20z 3

Overall Dimensions

Medium     20

Performance specification and characteristics

SAi20z and the line
Highest voltage for equipment

up to 24 kV for:

  • 3W systems with insulated, compensated neutral.

up to 21 kV for:

  • 3W and 4W systems with solidly grounded neutral;
  • Lines with overhead shielding/ground wire.
Maximum prospective fault current*, kA 1.5
Rated frequency, Hz 50 (±12)
Power frequency withstand voltage (for minimal 140 mm air gap), kV
SAi20z and lightning
High current impulse (4/10 μs), kA 65
Lightning discharge capability** (200 μs), C 2.4
Maximum fault quenching lightning current (8/50 μs), kA 3
Minimum withstand amount of operations 10
Additional power losses on the line, % 0
Weight, kg 1.0
Average life time expectancy, years 20 to 30
UV resistance***, h 1000
Time to install/pole, min. 10 to 20
Maintenance 1 visual verification per year
Additional Equipment cross-arm fitting and conductor clamp (glass indicator as an option)

* Maximum calculated short-circuit current in LLPD’s location;

** According to IEC 60099-8;

** According to ISO 4892-2, method A, IEC 62217.

Application Possibility Table

Footing resistance, Rf

3W systems (insulated, compensated neutral)

4W (solidly grounded neutral, overhead ground wire)

>10 0hm


YES, if capacity of transformers at a substation is below 20 MVA

5-10 Ohm

YES, if capacity of transformers at a substation is below 20 MVA

<5 Ohm

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1 piece per pole with phase alternation for ensuring reliable protection of an overhead line against IOV.

LLPD SAi20z must be installed with an air gap between its terminal electrode and conductor clamp. In order to select the proper value of the gap, please refer to the table.

Insulator’s CFO (kV)

SAi20z: Air gap (mm)


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Using bracket BPD.23

Using bracket BPD.38

Using bracket BCL.141

Test Certificates

Type of tests
Laboratory Year
High current impulse withstand test CESI (Milan, Italy) 2014
Lightning discharge capability test CESI (Milan, Italy) 2014
Standard Lightning Impulse Sparkover Test CESI (Milan, Italy) 2014
Impulse Withstand Test CESI (Milan, Italy) 2014
Temperature Cycling Test Salt Mist Test CESI (Milan, Italy) 2014
Vibration test CESI (Milan, Italy) 2014
Follow current interrupting test STRI (Witness test in Streamer's laboratory) 2014