GE Multilin 750-P5-G5-HI-A20-R Feeder Relay for 750 Series

GE Multilin 750-P5-G5-HI-A20-R Feeder Relay for 750 Series

The GE Multilin 750-P5-G5-HI-A20-R is a high-performance feeder protection relay engineered for seamless integration within the GE Multilin 750 Series control system architecture. Rather than functioning as a standalone device, this relay is designed to operate as a coordinated node within a layered automation hierarchy — connecting the protection layer, communication backbone, and supervisory control infrastructure into a unified, reliable system. Its role spans from real-time fault detection and isolation to upstream SCADA reporting and downstream breaker coordination, making it a critical component in any modern industrial protection scheme.

In distributed control environments — including power distribution substations, petrochemical process plants, water treatment facilities, mining operations, and heavy manufacturing lines — the 750-P5-G5-HI-A20-R delivers consistent protection performance while maintaining full system integration with adjacent system layers. Engineers deploying this relay benefit from its compatibility with the broader GE Multilin 750 Series ecosystem, enabling standardized configuration, coordinated protection settings, and simplified long-term maintenance across multi-feeder installations.

Product Specification Table

System Compatibility Notes

The 750-P5-G5-HI-A20-R achieves its full potential when deployed as part of a coordinated GE Multilin 750 Series protection scheme. At the control layer, it interfaces directly with the GE Multilin SR750 platform family, sharing a common configuration environment through EnerVista 750 Setup software, which dramatically reduces engineering time across multi-feeder projects. When paired with the GE Multilin 850 feeder protection relay in upstream bus protection roles, the two devices form a coordinated overcurrent protection hierarchy with precisely graded time-current characteristics.

At the I/O layer, the A20 output configuration provides 20 programmable output contacts, enabling direct hardwired integration with GE Multilin IAC Series electromechanical overcurrent relays used in legacy switchgear retrofits, as well as with modern GE Multilin 339 Motor Protection Relay units in motor feeder applications. The relay’s analog inputs accept signals from standard 5A CT secondaries and high-impedance voltage transformers, maintaining signal integrity across long cable runs in large substations.

At the network and communication layer, the G5 dual rear port configuration supports simultaneous Modbus RTU and DNP3.0 communication, enabling parallel connectivity to both a local GE Multilin EPM 7000 Power Meter network and an upstream SCADA system such as GE iFIX or a third-party DCS. This dual-port architecture eliminates the need for external communication switches in many substation designs, reducing panel footprint and potential failure points. For time synchronization, the relay supports IRIG-B input, ensuring microsecond-accurate event timestamping when coordinated with GPS-disciplined clocks across the protection network.

At the power supply layer, the relay’s wide-range auxiliary input is compatible with standard GE Multilin substation DC power systems operating at 110 VDC or 125 VDC battery-backed buses, as well as AC-fed UPS systems. This flexibility ensures uninterrupted relay operation during grid disturbances — a critical requirement in utility and industrial substation environments. When installed alongside GE Multilin PQM II Power Quality Meters, the combined system provides both protection and power quality monitoring from a single communication network segment.

At the human-machine interface layer, the relay’s front panel LCD and LED indicators provide local status visibility, while remote HMI integration is achieved through EnerVista Viewpoint Monitoring software or third-party SCADA displays. In redundant architecture designs, the 750-P5-G5-HI-A20-R can be configured in a primary/backup relay arrangement alongside a GE Multilin 750-P5-G5-HI-A20-R duplicate unit or a GE Multilin 735 Feeder Protection Relay as a cost-optimized backup, with automatic changeover logic implemented through the programmable output contacts and external logic controllers.

At the execution layer, the relay’s 20 output contacts directly drive ABB HD4 or GE Power Vac vacuum circuit breakers, lockout relays (86 devices), and motorized disconnects, completing the protection-to-execution signal chain without intermediate relay panels in most medium-voltage switchgear designs. This direct integration reduces wiring complexity, minimizes signal propagation delay, and improves overall system reliability — all backed by a warranty terms confirmed during quotation on every unit supplied.

Industrial Application Notes

Power Distribution & Utility Substations: The 750-P5-G5-HI-A20-R is widely deployed in 11 kV to 33 kV distribution substations for feeder protection, reclosing, and fault location. Its DNP3.0 communication capability enables direct integration with utility SCADA systems, supporting automated fault isolation and service restoration (FLISR) schemes. The relay’s directional overcurrent elements (67/67N) are particularly valuable in ring-main and meshed network topologies where fault current direction must be determined for correct relay coordination.

Petrochemical & Refinery Process Plants: In hazardous area process plants, the relay provides feeder protection for motor control centers (MCCs) and transformer feeders supplying critical process loads. Its wide operating temperature range and IP54 front panel rating make it suitable for installation in outdoor switchgear kiosks and climate-controlled relay rooms alike. The programmable logic capability allows plant engineers to implement custom interlock schemes without external PLCs, reducing panel complexity in SIL-rated safety systems.

Water Treatment & Pumping Stations: Municipal water authorities deploy the 750-P5-G5-HI-A20-R to protect feeder circuits supplying high-voltage pump motors and transformer banks. The relay’s reclosing function (79) is configured for single-shot or multi-shot reclosing on overhead feeder sections, while the sync-check element (25) prevents out-of-phase reclosing on tie feeders between pumping station bus sections. Modbus RTU communication integrates seamlessly with plant SCADA systems for remote monitoring and alarm management.

Mining & Metallurgical Operations: Underground and open-cut mining operations rely on the relay for protection of trailing cable feeders, dragline power systems, and concentrator plant distribution boards. The relay’s high-impedance voltage inputs and sensitive earth fault detection capability are essential for detecting high-resistance ground faults in resistance-earthed mining power systems, where conventional overcurrent relays may fail to operate. The warranty terms confirmed during quotation provides procurement teams with confidence in long-term parts availability for remote site maintenance programs.

Packaging & Manufacturing Production Lines: In automated manufacturing facilities, the relay protects feeder circuits supplying robotic welding stations, conveyor drive systems, and compressed air generation equipment. Its fast fault clearance time minimizes production downtime, while the event log and oscillography recording functions provide maintenance engineers with detailed fault data for root cause analysis and predictive maintenance planning.

Product Compatibility FAQ

Q1: Is the 750-P5-G5-HI-A20-R compatible with IEC 61850 communication protocols for modern digital substation integration?
The standard 750-P5-G5-HI-A20-R supports Modbus RTU and DNP3.0 via its G5 dual rear communication ports. IEC 61850 GOOSE messaging and MMS protocol support is available on selected firmware variants of the GE Multilin 750 Series platform. For IEC 61850-native substation automation projects, confirm the specific firmware version and order code with your supplier. All units supplied carry a warranty terms confirmed during quotation regardless of communication protocol configuration, ensuring full functional coverage from commissioning through the initial operational period.

Q2: How does the A20 output configuration support redundant tripping architectures in critical feeder applications?
The 20 programmable output contacts in the A20 configuration provide sufficient contact capacity to implement dual-trip coil schemes (TC1 and TC2) on circuit breakers equipped with redundant trip coils, as well as separate outputs for lockout relay (86) operation, alarm annunciation, SCADA binary outputs, and local panel indication. This eliminates the need for external output expansion modules in most medium-voltage feeder protection panels, simplifying the overall panel design and reducing potential failure points. The output contacts are rated for direct breaker trip coil duty, ensuring reliable operation under the high inrush currents associated with breaker trip coil energization.

Q3: What commissioning and long-term maintenance support is available for the 750-P5-G5-HI-A20-R, and what does the warranty terms confirmed during quotation cover?
Commissioning support is available through GE Multilin’s EnerVista 750 Setup software, which provides guided relay setting calculation, protection coordination tools, and automated commissioning test report generation. The relay supports secondary injection testing via its front panel test mode, compatible with standard relay test sets. The warranty terms confirmed during quotation covers all hardware defects, component failures, and functional non-conformances arising under normal operating conditions from the date of supply. Warranty claims are processed through ZYPLC’s technical support team, with replacement units dispatched from stock to minimize site downtime. Long-term spare parts availability is maintained to support 10+ year operational lifecycles typical of substation protection equipment.