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  1. D

    Loading power transformer

    Gratias Maximas !
  2. D

    Loading power transformer

    33KV/11KV, 15MVA, ONAN cooling. Transformer was de-energized and relocated to another substation. At the new substation, many of the tests in the chart you supplied were conducted and no problem was indicated. Transformer was then energised without incident but my supervisor said to not load...
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    Loading power transformer

    Thanks Phil ! But the chart only gives a procedure, it doesn't not specify any time duration for the transformer to be energised but unloaded.
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    Loading power transformer

    Thanks Dave. Let's say a 15MVA, 33KV/11KV unit has been out of service for 2 days due to a fault on the 33KV feeder. After the fault on the feeder has been repaired and the transformer successfully re-energized, how long should the transformer be on soak before being loaded ?
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    Loading power transformer

    Greetings. I have often come across the notion that newly commissioned power transformers and transformers that have been out of service due to a fault or outage should be kept on no-load for some hours before loading. I like to know the reason for this. Thanks.
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    Sympathetic Tripping

    Many thanks for your response. I am aware that lack of co-ordination between upstream and downstream feeders but that wasn't what I was referring to in my question. The circuit on page 9 of this link...
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    Sympathetic Tripping

    I am aware that sympathetic tripping occurs in resistance grounded systems where a feeder trips due to an earth fault occurring on another feeder. Does the phenomenon apply to solidly grounded MV feeders also? I have read an old post: "earth fault protection settings for an 11kV feeder,"...
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    Earth Fault Relay Settings for 11kv Distribution Feeders

    Thanks for your reply. >This is to avoid nuisance tripping. You don't want your >settings so tight that any small transient event will cause >an outage. Will transients typically or even sometimes result in earth fault current flowing, when there is no actual earth fault present? I...
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    Earth Fault Relay Settings for 11kv Distribution Feeders

    In the power distribution company where I work, the earth fault relays are usually set to 20% of the nominal feeder current. I have also seen online sources that specify between 10% and 20% for earth fault settings. I am aware that even in an unbalanced load situation, there is a very...
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