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How to configure separate overcurrent protection groups for transformer primary and secondary on Sepam T87

Customer would like to configure separate overcurrent protection for transformer primary and secondary on Sepam T87

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Sepam T87


  1. (Sepam settings -> CT/VT sensors) Configure the CT/VT Sensors. Note the locations of sensors (Ia, Ib, Ic) and sensors (I’a, I’b, I’c)
  2. (Protection settings -> 50/51) Select desired primary (Ia, Ib, Ic) or secondary (I’a, I’b, I’c) sensors for each unit from the “Measurement Origin” dropdown menu. These correspond to the line diagram configured in step 2
  3. (Protection settings -> 50/51) Verify desired measurement origin is selected, click the corresponding “On” checkbox and click “Apply” to apply changes
  4. (Protection settings -> 50/51) Configure tripping curves for each unit as required
* Please note that primary current I connects to B1 on the relay and secondary current I' connects to B2 on the relay. For the Sepam 80 wiring schematic, please refer to FA328719.
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