Why the Lighting Arrester used in 11KV is rate 9KV instead of 11KV

Answer QuestionsCategory: Discuss QuestionsWhy the Lighting Arrester used in 11KV is rate 9KV instead of 11KV
AJAZ UL HAQ Staff asked 3 weeks ago
1 Answers
Jousuf answered 2 weeks ago

Lighting Arrester provide protection against over voltage. It is connected between line to ground.
11KV is the line to line RMS (root mean square value) voltage.
The line to ground voltage = 11/√3 = 6.350 KV (rms)
Maximum line to ground voltage =6.350 *√2 = 8.980 = 9KV (Peak Value, rms = Peak / √2 )

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