GE Multilin 750/760 Feeder protection system

GE Multilin 750/760 Feeder protection system

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 in a draw out

construction and at a reduced product life cycle cost. 

Key Benefits

• Easy to use Feeder Protection System supported by industry leading suite of software tools

• Accurate built-in metering functions - Eliminates auxiliary metering devices and reduces cost

• Improve uptime of auxiliary equipment - I/O monitoring

• Reduce troubleshooting time and maintenance costs - IRIG-B time synchronization, event reports,

waveform capture, data logger

• Minimize replacement time - Draw-out construction

• Simplify testing - Built in simulation features

• Cost effective access to information. Supports industry protocols such as DNP & Modbus. Includes an

optional 10MB Ethernet port for system integration

• Complete asset monitoring - Analog I/O, Full metering including demand & energy

• Leading edge technology - Flash memory for product field upgrade

• Extended life - Optional conformal coating for chemically corrosive and humid environments

• Globally accepted ensuring adherence to international codes and standards

Applications

• Primary protection and control for distribution feeders on solidly grounded, high impedance grounded

or resonant (Peterson Coil) grounded systems

• Bus blocking/Interlocking schemes

• High-speed fault detection for arc flash mitigation

• Throw over schemes (bus transfer scheme applications)

• Load shedding schemes based on voltage and frequency elements

• Back-up protection for transmission lines, feeders and transformers

• Distributed Generation (DG) interconnect protection

Protection and Control

• Directional time, instantaneous phase &

ground overcurrent protection

• Directional sensitive ground and Restricted

Earth Fault protection

• Reverse power protection

• Synchro Check - V, f, Hz, & dead-source

• Automatic bus transfer or manual control

• 4 shot recloser (760 only)

Communications

• Networking interfaces - 10Mbps Ethernet,

RS232, RS485 and RS422 ports

• Ethernet port, 10Mbps

• Multiple protocols - ModBus™ RTU, TCP/IP,

DNP 3.0 Level 2

Monitoring & Metering

• Metering - current, voltage, sequence

components, power, energy, voltage

• Breaker operation & trip failure

• Total breaker arcing current

• Ambient temperature /analog transducer input

• Oscillography & Data Logger - 10 records up

to 32 power cycles

• Simulation mode and playback capability

EnerVista Software

• State of the art software for configuration and

commissioning Multilin products

• Document and software archiving toolset to

ensure reference material and device utilities

are up-to-date

• EnerVista™ Integrator providing easy

integration of data in the 750/760 into new or

existing monitoring and control systems

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.

Time & Instantaneous Overcurrent

The 750/760 has two phase TOC elements with

level detectors for each phase. The 750/760 also

has two overcurrent elements most commonly

used for primary and back up protection. Each

TOC element has the following programmable

characteristics:

• Pickup current level for trip, alarm, or control

• Choice of 15 curve shapes (including

FlexCurves) and curve multipliers

• Instantaneous or linear reset time

characteristic

• Voltage restraint

Standard and Flex Curves

The 750/760 has two phase IOC elements

with level detectors for each phase. Each IOC

element has a programmable pickup current,

a time delay during which current must exceed

the pickup for operation, and the minimum

number of phases required for operation.

Ground overcurrent protection

Solidly grounded and low impedance grounded

distribution systems requiring fast clearing of

ground faults to limit equipment damage. The

following functions are incorporated in the

750/760 to provide ground fault protection

• Neutral IOC and TOC

• Ground IOC and TOC

750/760 allows directional elements to be used

to supervise the ground overcurrent protection

elements. This means the 750/760 can be used

to provide sensitive tripping for faults in one

direction. Typical applications for directional

overcurrent include:

• Isolation of the faulted feeder in ring bus or

parallel feeder arrangements.

• Prevention of back-feeding utility source fault

from industrial plant generators

• Sensitive hi-speed ground protection of

transformers

Sensitive ground and Restricted Earth Fault (REF)

protection

Sensitive ground and RGF protection features

provide sensitive detection of ground faults.

Sensitive ground fault protection includes:

• Instantaneous (50N) & Tim (51N) - 2 levels

• Directional supervision allows to discriminate

between forward and reverse faults.

• Dual polarization (current & voltage) provides

max security and reliability

750/ 760 employed to provide transformer back

up protection (grounded wye windings and

autotransformers) using the RGF feature.

Voltage Protection

Overvoltage/Undervoltage protection features

can cause a trip or generate an alarm when the

voltage exceeds a specified voltage setting for

a specified time. Voltage protection includes a

negative sequence voltage element to detect

abnormal system unbalance conditions, and a

neutral displacement voltage element using the

calculated zero sequence voltage (3V0) to detect

ground faults.