UR8LA GE Multilin CT/VT Module

Configured for power system signal acquisition in Universal Relay (UR) platforms, the GE Multilin UR8LA (UR8LA CT/VT Module) provides direct physical/electrical execution of current and voltage transformer signal conversion for protection and control loops.

Hardware Specifications

Industrial Control and Network Characteristics

• Backplane bus communication velocity: The module utilizes the high-speed Universal Relay backplane to transmit digitized waveform data to the main processing unit. This velocity is necessary for supporting sub-cycle protection algorithms, such as 87L differential protection, which typically executes in less than 1 cycle.
• Profinet / EtherNet/IP deterministic networks: The UR8LA integrates into networks supporting IEC 61850, DNP 3.0, and Modbus RTU protocols. This allows for high-speed interoperability and deterministic data exchange with SCADA and station-level automation systems.
• I/O density scaling: The module supports flexible scaling of current and voltage inputs, with configurations accommodating up to 11 CTs and 4 VTs, enabling the construction of complex protection schemes within a singular relay chassis.
• Firmware flash compatibility: The hardware platform supports field-level firmware upgrades, ensuring the module remains aligned with evolving communication standards (PRP/HSR) and protection logic requirements without hardware replacement.

Frequently Asked Questions

Q: Is the UR8LA compatible with all UR series relays?

A: Yes, the UR8LA is designed for full compatibility with the GE Multilin UR series relay platform. Ensure that the relay firmware and chassis backplane revision are updated to support the specific I/O mapping required by this module.

Q: Can the module be replaced without shutting down the system?

A: Yes, the UR8LA features a hot-swappable design. It can be extracted or inserted while the relay chassis remains energized, though standard utility safety practices regarding secondary CT circuit shorting must be observed before physical removal.

Field Installation Guidelines

• Mounting: Insert the module into the designated UR relay slot and secure the locking levers. Ensure the backplane connector is fully mated to maintain the high-integrity contact required for low-level CT and VT signal paths.
• Grounding: The UR chassis must be connected to the substation earth bus via a low-impedance ground strap. A solid ground connection is mandatory to prevent electromagnetic interference (EMI) from affecting the analog-to-digital conversion process.
• Wiring: Use shielded, twisted-pair cabling for all CT and VT inputs. Route these signal lines through dedicated conduit, ensuring a minimum separation of 150 mm from high-voltage AC lines to mitigate inductive noise coupling that can cause maloperation of protection elements.