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NAA Auxiliary Relay

The Type NAA relay is the general designation of a large family of special purpose auxiliary relays. Most NAA relays have two or more telephone type auxiliaries mounted in the regular draw out case. In some specific types an overcurrent function may also be included.

End of life notice: The NAA will be discontinued as of October 1, 2013.



  • Ground distance auxiliary (NAA15)

  • Out-of-step auxiliary (NAA19)

  • Transferred tripping auxiliary (NAA27)

  • Relay Supervision (NAA30)


Protection and Control

  • Application specific configurations

  • Adjustable pickup/dropout times


NAA Brochure

NAA Manual

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