Protection Functions: Supports various protection functions like overcurrent protection (3I>, 3I>>, 3I>>>), earth fault protection (Io>), and more.
Communication Protocols: Supports serial communication using protocols like SPA, IEC, MODBUS, and LON.
Display Module: Includes a 6 x 16 character display for easy local operation and monitoring.
Self-Supervision: Equipped with autodiagnostic circuits to ensure high reliability and avoid false operations.
Technical Specifications
Feature
Details
Digital Inputs
9
High-speed Power Outputs
1
Power Outputs (PO)
3
Signalling Outputs (SO)
2
IRF Outputs
1
Trip-Circuit Supervision (TCS)
1
Power Supply Modules
PS_87H: DI threshold = 80 VDC
PS_87L: DI threshold = 18 VDC
Applications
The REX 521 is ideal for protecting incoming and outgoing feeders in medium voltage distribution substations. It can also be used as backup protection for power transformers and high voltage line protection relays.
