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

    The 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 40 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