General Notes: Binary I/O shown is from default PCM600 Application Configuration Tool (ACT). Connections shown are typical though more connections may be needed for specific application.. Learn about Restricted Earth Fault relay (REF Relay) for transformer protection including wiring diagram, operation and relay settings.
This manual contains application and functionality descriptions and connection diagrams, input and output signals, setting parameters and technical data. The manual can be used as a technical reference during the engineering phase, installation and commissioning phase, and during normal service. The manual can also be used when calculating.. REF Protection Definition: REF protection is a scheme used in transformers to detect internal earth faults by monitoring unbalanced currents in the transformer phases and neutral. External Fault Current Flow: During an external fault, balanced currents in the line CT and neutral CT result in zero net current in the relay, preventing activation.