ABB REO 517 Applications Manual page 19

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Application
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The main purpose of the REO 517 terminal is the protection, control and monitoring of
railway electric power systems in single or two-phase high impedance or solidly
earthed railway systems, which is running at 16 2/3, 50 or 60 Hz. It is suitable for the
protection of lines where the load varies within wide limits due to train operation. The
terminal may also be used to provide backup protection for power transformers, bus-
bars, etc.
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