सर्ज प्रोटेक्शन कैलकुलेटर — सूत्र

Surge Protection Device Sizing

SPDs must absorb surge energy while limiting voltage to a safe clamping level that protects downstream equipment.

Formulas

V_clamp = V_peak x Clamping Ratio

Energy = V_clamp x I_surge x Duration

The standard test waveform for SPDs is 8/20 microseconds (8 us rise, 20 us to half-value).

SPD Categories (IEC 61643)

  • Type 1: Lightning current (10/350 us), installed at service entrance
  • Type 2: Surge current (8/20 us), at distribution panel
  • Type 3: Combination wave, at point of use

    • हल किया गया उदाहरण

    230 V system, 10 kA surge (8/20 us), MOV clamping ratio 2.5x.

    1. System peak: 230 x sqrt(2) = 325 V
    2. Clamping voltage: 325 x 2.5 = 813 V
    3. Energy: 813 x 10,000 x 20e-6 = 162.6 J
    4. Peak power: 813 x 10 = 8,130 kW