Category Archives for Relay Elements

A New Transmission Line Protection (21) Video

End-to-End Testing can appear to be a daunting task. However, any relay tester can perform successful End-to-End Tests with a basic understanding of transmission line protection (or 21 impedance protection)

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Finding the Direction in Directional Overcurrent Relays

A reader recently asked a question about the forward and reverse directions described in the Directional Overcurrent Relay section of The Relay Testing Handbook series.  I used electro-mechanical directional

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Distance or Impedance Protection (21) Video

Line distance (21) protection is primarily used to protect transmission lines or other electrical equipment where the equipment’s impedance characteristic can be calculated or modeled with software

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Good Directional Overcurrent Protection (67) Video

Instantaneous overcurrent (50) and time overcurrent (51) protection can protect equipment from overloads and short circuits, but there are situations where their ability to protect a system is limited.

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Testing Basler BE1-47N Negative Sequence Voltage Relays

Testing more complicated elements that use a percentage or ratio between values can be difficult if you cannot properly define all of the values in the equation.  It doesn’t help that different

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Real World Problem With an SEL-300G Synch-Check

Here is a story from one of our Customers at Manta Test Systems: “I had to troubleshoot a Schweitzer SEL-300G relay yesterday that had the (25) Sync-Check element enabled, but wouldn’t assert the

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