The General Electric Multilin 350-E-P5-G5-H-E-E-N-N-SN-D-N, also cataloged as the 350 Feeder Protection Relay, operates as a dedicated hardware component for distribution system monitoring and fault clearing within industrial and utility power networks.

Suffix Breakdown & Model Matrix

• 350: Base Model Feeder Protection Relay
• E: Enhanced protection and control model
• P5: Standard protection suite (5 A CT inputs)
• G5: Enhanced communication interface (RS485)
• H: High-range power supply (125-250 VDC / 100-240 VAC)
• E: Ethernet communication support
• E, N, N, SN, D, N: Factory configuration settings for I/O logic and auxiliary enclosure features

Hardware Specifications

Profinet / EtherNet/IP Deterministic Networks

The 350 relay utilizes deterministic network communication to ensure that high-priority protection data, such as trip signals and arc flash detection flags, are transmitted across the distribution bus without packet collision or latency jitter. The inclusion of Ethernet connectivity allows for real-time integration into site-wide SCADA systems, where temporal synchronization (via SNTP or similar protocols) is required for sequence-of-events recording. This ensures that fault-clearing operations and multi-shot reclosing sequences are executed with absolute timing reliability.

Frequently Asked Questions (FAQ)

Q: What is the purpose of the 86 lockout relay feature in the 350 series?

A: The 86 lockout relay function provides a software-defined mechanical or electronic latch that prevents the circuit breaker from re-closing after a severe fault until a manual or remote reset command is received. This prevents repetitive damage to system components during a permanent fault condition.

Q: Can the 350 relay arc flash protection be used without external light sensors?

A: Arc flash protection in the 350 series typically relies on the simultaneous detection of overcurrent and intense light. While the relay provides the internal logic, external light sensors are required to verify the presence of an arc flash; relying on overcurrent alone is insufficient to differentiate an internal arc from a remote feeder fault.

Field Installation Guidelines

1. Ensure the relay is mounted in a panel with adequate ventilation to prevent thermal degradation of the internal components.
2. Verify the grounding lug is connected to the cabinet ground bus using a flexible braided copper cable to minimize the effect of high-frequency interference during fault clearing.
3. When wiring the 10 contact inputs, ensure all circuits are isolated from hazardous voltages or properly insulated, as these are low-voltage signal inputs.
4. Verify the phase rotation of the 3-phase voltage and current inputs matches the system installation documentation to avoid incorrect operation of directional protection elements.
5. Tighten all terminal connections to the specified torque values and verify continuity for all current input loops before energizing the feeder.