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Which relay is used to protect feeders?

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    Which relay is used to protect feeders?

    So the question reads:

    "Which relay is used to protect feeders?" and the possible answers are:

    - MHO relay
    - Translay Relay
    - Merz Price Relay
    - Buchholz Relay

    Quite honestly, none of these answers seem 100% right. A MHO relay is used for distance protection on a line, a translay relay is used for line differential protection via a pilot scheme, a Merz Price relay is used for generator differential protection, and a Buchholz relay is used for transformer protection. I know the "correct answer" for the practice quiz isn't a MHO relay because I picked that and it was wrong, but then the only other choice that would make sense is a translay relay, but technically it isn't protecting a feeder, it is protecting the line. In that case, the MHO relay could also be seen as a viable choice because it protects a line too. So why is translay correct and MHO not correct?

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    Quote Originally Posted by EricGoetz92 View Post
    So the question reads:

    "Which relay is used to protect feeders?" and the possible answers are:

    - MHO relay
    - Translay Relay
    - Merz Price Relay
    - Buchholz Relay

    Quite honestly, none of these answers seem 100% right. A MHO relay is used for distance protection on a line, a translay relay is used for line differential protection via a pilot scheme, a Merz Price relay is used for generator differential protection, and a Buchholz relay is used for transformer protection. I know the "correct answer" for the practice quiz isn't a MHO relay because I picked that and it was wrong, but then the only other choice that would make sense is a translay relay, but technically it isn't protecting a feeder, it is protecting the line. In that case, the MHO relay could also be seen as a viable choice because it protects a line too. So why is translay correct and MHO not correct?
    MHO seems like the best answer to me. Based on the answer options, I'd say the questions is referring to line protection and using the general term "feeder" as a distractor. I'd be curious to see what some of the more experienced relay guys say about this.

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    Quote Originally Posted by SecondGen View Post
    MHO seems like the best answer to me. Based on the answer options, I'd say the questions is referring to line protection and using the general term "feeder" as a distractor. I'd be curious to see what some of the more experienced relay guys say about this.
    MHO also seems pretty correct to me, but it was marked wrong by the practice test. I would also like to see what more experience relay guys would say, but I have a feeling this question is poorly written or the answer choices weren't thought out all the way and multiple technically right answers were put in there.

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    I also chose the MHO as the answer and I have been doing this a while. Curious to know what they say is the right answer.

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    Quote Originally Posted by EricGoetz92 View Post
    So the question reads:

    "Which relay is used to protect feeders?" and the possible answers are:

    - MHO relay
    - Translay Relay
    - Merz Price Relay
    - Buchholz Relay

    Quite honestly, none of these answers seem 100% right. A MHO relay is used for distance protection on a line, a translay relay is used for line differential protection via a pilot scheme, a Merz Price relay is used for generator differential protection, and a Buchholz relay is used for transformer protection. I know the "correct answer" for the practice quiz isn't a MHO relay because I picked that and it was wrong, but then the only other choice that would make sense is a translay relay, but technically it isn't protecting a feeder, it is protecting the line. In that case, the MHO relay could also be seen as a viable choice because it protects a line too. So why is translay correct and MHO not correct?
    I had just read your post before taking the test. I picked Translay and it was marked as correct.

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    Quote Originally Posted by EricGoetz92 View Post
    So the question reads:

    "Which relay is used to protect feeders?" and the possible answers are:

    - MHO relay
    - Translay Relay
    - Merz Price Relay
    - Buchholz Relay

    Quite honestly, none of these answers seem 100% right. A MHO relay is used for distance protection on a line, a translay relay is used for line differential protection via a pilot scheme, a Merz Price relay is used for generator differential protection, and a Buchholz relay is used for transformer protection. I know the "correct answer" for the practice quiz isn't a MHO relay because I picked that and it was wrong, but then the only other choice that would make sense is a translay relay, but technically it isn't protecting a feeder, it is protecting the line. In that case, the MHO relay could also be seen as a viable choice because it protects a line too. So why is translay correct and MHO not correct?

    I agree, I do not particularly like this question since feeder is a broad term. Especially since a large portion of feeder breakers do feed transformers. You'd really have to know the definition of some of each of these relays. This explained translay relays to me since I rarely come across these.
    https://www.electrical4u.com/differential-relay/

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