GE Multilin UR-8RH Universal Relay CT/VT Module

GE Multilin UR 8RH CT/VT Input Module

Configured for sensitive‑ground CT/VT acquisition in UR‑series protection networks, the GE Multilin UR 8RH (UR 8RH CT/VT Input Module) provides direct analog front‑end processing for phase, ground, and auxiliary measurement channels with enhanced diagnostic capability.

Hardware Specifications

Eddy‑Current Probe Scaling & Cross‑Talk Suppression

Although the UR‑8RH is an electrical‑measurement module, GE Multilin’s analog‑conditioning design follows principles similar to turbine supervisory interfaces. Sensitive‑ground channels use high‑resolution scaling comparable to eddy‑current probe biasing, ensuring stable detection of high‑impedance ground faults. Channel‑to‑channel isolation suppresses cross‑talk, preventing induced noise from adjacent CT circuits. Reference‑voltage validation—analogous to gap‑voltage checks in probe systems—supports deterministic scaling across all CT/VT inputs, improving relay element performance under transient conditions.

Frequently Asked Questions

Q: What makes the UR‑8RH different from older CT/VT modules? A: It includes sensitive‑ground 8CT capability and enhanced diagnostics, requiring firmware 4.0x or newer.

Q: Can the UR‑8RH be used with older CPU modules? A: It is recommended to pair new CT/VT modules with newer CPUs to avoid hardware‑mismatch errors.

Q: Does the UR‑8RH support hot‑swap insertion? A: No. The relay must be de‑energized before inserting or removing the module.

Field Installation Guidelines

• De‑energize the relay before handling the module to avoid transient analog‑input disturbances.
• Route CT/VT wiring separately from digital I/O conductors to reduce noise coupling.
• Maintain shield continuity and ground shields at a single termination point to avoid ground‑loop interference.
• Verify terminal torque and polarity on CT/VT connections before energizing.
• Use EnerVista UR to validate sensitive‑ground scaling and confirm correct phasing during commissioning.