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Protection Relays
Feeder Protection

Home > Grid Automation > Protection Relays > Feeder Protection > 350

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Multilin 350
Intuitive and innovative feeder protection system

The Multilin™ 350 is a member of the Multilin 3 Series protective relay platform and has been designed for the protection, control and management of feeders or related applications as a primary or backup protection device. This cost-effective protective device is used to perform advanced feeder protection, control and monitoring for low, medium and high voltage applications. The 350 also offers enhanced features such as integrated arc flash protection, metering, monitoring and diagnostics, preventative maintenance, advanced communications and security.

The 350 protection relay chassis used with a draw out relay is available separately, for use as a partial replacement or in test environments. The draw out relay with no chassis is also available to order as a spare unit.

Key Benefits

  • Cost-effective and flexible protection and control
  • Field-proven algorithms and reliable protection to avoid unwanted trips or under-protection
  • Ease of use and standardization with one-step setup and universal CT inputs
  • Environmental monitoring system to monitor operating conditions and plan preventative maintenance
  • Advanced power system and switchgear diagnostics
  • Flexible communications with multiple ports and protocols allowing seamless integration
  • Arc flash mitigation via zone inter-tripping, flex curves and multiple elements and setting groups
  • Integrated arc flash detection using light sensors supervised by over current to reduce incident energy and damage
  • Powerful Security and hierarchical password control for centralized management
  • Application flexibility with the use of programmable logic elements
  • Drawout design simplifies, commissioning and maintenance, thereby increasing process uptime
  • Increased network availability with zero failover time through IEC® 62439-3 PRP and HSR support
  • Precise time synchronization through IEEE® 1588 (Precise Time Protocol (PTP)) support
  • Robust design exceeding industry standards, with Automotive Grade components and advanced testing procedures such as accelerated life cycle testing
  • Simplified migration of legacy MII Family relays to the 3 Series platform
  • Intuitive configuration software and user-friendly logic configuration tool


  • Primary protection and control for medium and high voltage utility and industrial overhead or cable feeder applications
  • Protection of small and medium size distribution transformers
  • Back-up protection of various HV applications
  • Capacitor bank protection
  • Advanced control applications including Cold Load Pickup, multi-shot recloser and multiple setting groups
Protection & Control
Monitoring & Metering

Key Features

  • Comprehensive current, voltage and frequency protection functions
  • Directional Power and Wattmetric Ground Fault
  • Wide variety of protection curves
  • Synchrocheck, CLP, 2nd Harmonic Blocking, Breaker Failure and Lockout functions
  • Cold Load Pick Up
  • Breaker failure, overload
  • Autoreclose
  • Integrated arc flash protection

Protection & Control

The 350 relay is a member of the 3 Series family of Multilin relays. This protective device is used to perform primary or back-up circuit protection on medium or high voltage feeders or transformers and down stream protection for utility and industrial switchgear. The 350 can be used for a wide variety of protection applications in power systems such as HV/MV or MV/LV transformer protection or capacitor bank protection. The basic protection provided by this relay includes multiple phase, ground, and neutral time and instantaneous overcurrent elements for coordination with upstream and downstream devices. Now it is enhanced with integrated arc flash detection functionality using light sensors supervised by over current to reduce incident energy and equipment damage. Additionally, the device provides essential feeder control features such as cold load pick up blocking, 2nd harmonic blocking, breaker failure, synchrocheck and autoreclose.

The robust 350 streamlines user work flow processes and simplifies engineering tasks such as configuration, wiring, testing, commissioning and maintenance.

Multilin 350 feeder protection relay functional block diagram

350 Functional Block Diagram

ANSI® Device Numbers & Functions

Device Number 61850 Logical Node Description
24 PVPH Volts per Hertz
25 RSYN Synchrocheck
27_1 psseqPTUV Positive Sequence Undervoltage
27P phsPTU Phase Undervoltage
27X auxPTUV Auxiliary Undervoltage
32 PDOP Directional Power
32N ndPDOP Wattmetric Ground Fault
I1/I2 OR 46BC   Broken Conductor
49 PTTR Thermal Overload
50_2 ngseqPIOC Negative Sequence Overcurrent
50BF RBRF Breaker Failure
50G/SG gndPIOC/hsePIOC Ground (or Sensitive Ground) Instantaneous Overcurrent
50N ndPIOC Neutral Instantaneous Overcurrent
50P phsPIOC Phase Instantaneous Overcurrent
51_2 ngseqPTOC Negative Sequence Time Overcurrent
51N ndPTOC Neutral Time Overcurrent
Device Number 61850 Logical Node Description
51G/SG gndPTOC/hsePTOC Ground (or Sensitive Ground) Time Overcurrent
51P phsPTOC Phase Time Overcurrent
59_2 ngseqPTOV Negative Sequence Overvoltage
59N ndPTOV Neutral Overvoltage
59P phsPTOV Phase Overvoltage
59X auxPTOV Auxiliary Overvoltage
60CTS   CT Supervision
67G/SG gndRDIR Ground (or Sensitive Ground) Directional Element
67N ndRDIR Neutral Directional Element
67P phsRDIR Phase Directional Element
79 RREC Autoreclose
81O PTOF Overfrequency
81U PTUF Underfrequency
86   Lockout
CLP   Cold Load Pickup
VTFF (60VTS)   Voltage Fuse Failure
350 logic diagram
Sixteen logic elements available for applications such as manual control, interlocking and peer to peer tripping.

Key Features

  • Comprehensive metering
  • Event Recorder: 256 events (1ms time stamping)
  • Programmable oscillography up to 32 samples per cycle and digital states and Fault Report
  • Relay health diagnostics
  • Breaker monitoring and CT/VT supervision
  • Security and password control
  • SNTP, IRIG-B or IEEE 1588 time synchronization

Power System Troubleshooting

Analyze power system disturbances with transient fault recorder and event records

Monitoring & Diagnostics

Metering, Monitoring & Diagnostics

  • IEEE 1588 (Precise Time Protocol) and IRIG-B:
    IEEE 1588 synchronizes time between different nodes on an Ethernet network when precise time synchronization is required, and IRIG-B allows time stamping of events to be synchronized among connected devices within 1 millisecond.
  • Trip/Close Coil Monitoring
    The 350 can be used to monitor the integrity of both the breaker trip and closing coils and circuits. The supervision inputs monitor both the auxiliary voltage levels, while the outputs monitor the continuity of the trip and/or closing circuits, by applying a small current through the circuits.
  • Temperature Monitoring:
    The 350 continually monitors ambient temperature around the relay and alarms when device is exposed to extreme temperatures.
  • Advanced Device Health Diagnostic:
    These diagnostic tests monitor for conditions that could impact and present device status via SCADA communications and front panel display.

Key Features

  • Front USB and rear serial, Ethernet, fiber and dual port options for seamless redundancy (IEC 62439-3, PRP & HSR)
  • Multiple communication protocols supporting industry leading standards

Advanced Communications

The 350 incorporates the latest communication technologies, making it the easiest and the most flexible feeder protection relay for use and integration into new and existing infrastructures. The 350 relay provides the user with one front USB and one rear RS485 communication port. Also available with the 350 is a rear communication port with Ethernet Fiber and Copper. For configurations requiring PRP and HSR redundancy protocols, the 350 provides two rear Fiber ports. Through the use of these ports, continuous monitoring and control from a remote computer, SCADA system or PLC is possible.

The 350 provides optional Parallel Redundancy Protocol (PRP) and High Availability Seamless Ring (HSR) according to the IEC 62439-3 standard that defines two protocols to increase network availability by reducing failover time to zero. Both ports are capable of simultaneously supporting the following protocols: Modbus TCP/ IP, IEC 61850, DNP3 or IEC 60870-5-104, IEEE 1588, SNTP and OPC-UA.

Link Loss Alert (LLA) function detects any issue with one port and switch to the other one in case of failure.

The 350 supports popular industry-leading standard protocols enabling easy, direct integration into electrical SCADA and HMI systems. The protocols supported by the 350 include:

  • IEC 61850
  • IEC 61850 GOOSE
  • DNP 3.0
  • Modbus RTU
  • Modbus TCP/IP
  • IEC 60870-5-103
  • IEC 60870-5-104
  • PRP & HSR (IEC 62439-3)
  • Link Loss Alert (LLA)
  • OPC-UA
  • IEEE 1588 for time synchronization

Example of redundant HSR and PRP Architecture

Example of redundant HSR and PRP Architecture

Redundancy protocols can be used for various networking architectures including combined PRP / HSR technologies.

EnerVista Software

The EnerVista suite is an industry leading set of software programs that simplifies every aspect of using the 350 relay. The EnerVista suite provides all the tools to monitor the status of the protected asset, maintain the relay, and integrate the information measured into DCS or SCADA monitoring systems. Convenient COMTRADE and sequence of event viewers are an integral part of the 350 set up software and are included to ensure proper protection and system. Learn More

3 Series setup software protection summary for viewing a summary of Protection & Control configuration

Access Control

With the Security Audit Trail reporting feature, available in GE’s ViewPoint Monitoring software, operators are able to obtain Event logging reports of key activities such as configuration changes. These pre-formatted reports can be used to help ensure device and protection system integrity and perform forensic auditing of activities and changes for compliance.

Security audit trail sample screen

Trace any setting changes with security audit trail.

Key Features

  • 4 line display for easy viewing of key data
  • 12/10 LED indicators for quick diagnostics
  • Programmable LED indicators for specific targets
  • Draw out or non draw out design options


Inputs and Outputs
The 350 features the following inputs and outputs for monitoring and control of typical feeder applications:

  • 10 contact Inputs with programmable thresholds
  • 2 Form A outputs for breaker trip and close with coil monitoring and 5 Form C output relays

Drawout & Non-Drawout Construction
The 350 is offered in both a drawout or a nondrawout construction. In the drawout case design the 350 simplifies installation and improves site safety as the need to open switchgear doors or rewire the device after testing is eliminated.

The 350 protection relay chassis used with a draw out relay is available separately, for use as a partial replacement or in test environments. The draw out relay with no chassis is also available to order as a spare unit.

Application Flexibility & Ease of Wiring
Removable terminals ease wiring and in-system testing or troubleshooting.

Drawout relay Drawout
Non-drawout relay Non-drawout

User Interface

User Interface

Retrofit Existing Multilin MII Family Devices

Traditionally, retrofitting or upgrading an existing relay has been a challenging and time consuming task often requiring re-engineering, panel modifications and re-wiring. Similar features and form factor of some models of MII family devices allow users to replace their existing relays with 3 Series relays with enhanced protection and control features and advanced communications.

The SR3 Enervista Setup software allows users to create new setting files based on existing MIFII and MIVII setting files and can be uploaded to a 350 relay with a compatible model number. Retrofit is smooth and simplified with minor wiring or switchgear modifications.

3 Series retrofit