GE Multilin 750/760 - Legacy Feeder Protection System

GE Multilin 750/760 - Legacy

Feeder Protection System

Manufacturing for 750/760 has been discontinued. As an alternative, please refer to the 850.

The 750/760 Feeder Protection System, a member of the SR Family of protection relays, with draw out capability intended for primary protection and management of distribution feeders. 

The 750/760 has specific features for industrial environments, including a drawout case to limit downtime during maintenance and conformal coating for harsh environments.

Key Benefits

Easy to use protection supported by industry leading software

Accurate built-in metering functions

I/O monitoring - improve uptime

IRIG-B time synchronization, event reports, waveform capture, data logger

Minimize replacement time

Draw-out construction

Simplify testing - Built in simulation features

Supports industry protocols such as DNP & Modbus

Optional 10MB Ethernet port

Complete monitoring - Analog I/O, Full metering

Leading edge technology - Flash memory for product field upgrade

Optional conformal coating for Harsh Environments

Applications

Primary protection and control for distribution feeders on solidly grounded, high impedance grounded or resonant grounded systems

Bus blocking/Interlocking schemes

High-speed fault detection for arc flash

Throw over schemes (bus transfer scheme)

Load shedding schemes based on voltage and frequency elements

Back-up protection for transmission lines, feeders and transformers

Distributed Generation (DG) interconnect protection

Key Features

Directional time, instantaneous phase overcurrent protection

Directional time, instantaneous ground overcurrent protection

Directional sensitive ground and Restricted Earth Fault protection

Negative sequence overcurrent protection

Bus and line undervoltage

Overvoltage

Neutral overvoltage

Underfrequency/Frequency decay

Reverse power protection

Synchrocheck

Automatic bus transfer

Manual control

Cold load pickup control

Power factor control

4 shot recloser (760 only)

Power factor control

Synchrocheck - V, f, Hz, & dead-source

Protection and Control

The 750/760 Feeder Protection System is a digital relay intended for the management and primary protection and control of distribution feeders. 

This easy to use relay provides comprehensive protection functions for feeders and back up protection for bus, transformers and transmission lines at a reduced product life cycle cost.

Key Features

Metering - current,voltage, sequence components, power, energy, voltage

Breaker operation & trip failure

Event recording - 128 time tagged events

Total breaker arcing current

Ambient temperature /analog transducer input

Analog transducer input

Oscillography & Data Logger - 10 records up to 32 power cycles

Simulation mode and playback capability.

Monitoring and Metering

The 750/760 features advanced monitoring and metering functions which include:

Fault Locator

The relay uses captured data to calculate the type, distance to and the impedance of the fault. Records of the last 10 faults are stored.

Breaker Conditions

The relay calculates the per-phase wear on the breaker contacts to establish a threshold. When the breaker maintenance threshold is exceeded the relay can trigger an alarm. 

An alarm is also generated if the relay detects that the supervisory trickle current is not present. A failure to respond to an open or close signal in a programmed time can be used to generate an alarm.

VT Failure

The VT failure feature monitors each phase of input voltage, generating an alarm and sending the programmed output signals when a failure is detected.

Analog Inputs

Any external quantity may be monitored via an auxiliary current input. Two analog input level monitoring elements and two rate-of-change elements are available. 

When the measured quantity exceeds the pickup level, the relay can trigger an alarm or signal an output.

Event Recording

The relay captures and stores the last 512 events, recording the time, date, cause, and system parameters. Events may be recorded selectively by category, so that only events of interest are recorded.

Oscillography

A block of configurable volatile memory can be used for recording samples of the AC input voltages and current, and the status of logic inputs and output relays. 

This memory can be configured between the ranges of two to 16 blocks with 16 to 256 power frequency cycles of data respectively. 

The amount of pre-event data recorded is set by the user. Trace memory recording can be triggered by operation of selected features or logic inputs.

Trip Counter

The number of breaker trip operations is recorded, and can be displayed for statistical purposes (useful for units without operation counters).

Key Features

Networking interfaces - 10Mbps Ethernet, RS232. RS485 and RS422 ports

Ethernet port, 10Mbps

Multiple protocols - ModBus™ RTU, ModBus™ RTU, TCP/IP, DNP 3.0 Level 2

Advanced Communications

The 750/760 is equipped with three standard serial communications ports, one RS232 located in the front panel, and two RS485/RS422 in the rear of the relay. A rear Ethernet port is also available as an optional feature. 

The front panel port allows easy local computer access. The rear ports provide remote communications or connection to a DCS, SCADA, or PLC.