Forums » Electrical Engineering

Transformer phase lost

    • 25 posts
    January 21, 2020 8:52 AM PST

    for a oil transformer, if one phase is lost and run transformer for long time, will this cause a damage to transformer? how about if this happens under no load connected?

    • 103 posts
    January 21, 2020 5:56 PM PST

    I do not see how an unloaded three phase transformer would be harmed by this in most cases.  Unless the event that caused the phase loss also produced an overvoltage transient or fault.  Sitting unloaded the transformer could be susceptible to ferroresonance.

    A lost phase on a loaded three phase transformer would probably be more detrimental to it's loads than the transformer itself.  I think it would mostly depend on the transformer configuration, Dd or Yd...