Which outcome occurs when a high-voltage DC transmission circuit breaker experiences a commutation failure?

💡 Explanation

When forced commutation fails in an HVDC circuit breaker, reverse voltage cannot be applied to turn off the conducting thyristors, leading to reverse current flow because the AC voltage phase changes polarity. Therefore, reverse current occurs, rather than a voltage spike, harmonics, or overheating, which are associated with related though distinct failure modes.

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