GE Multilin 350 - Page 8

350 Feeder Protection System
273
Distribution Feeder Protection
flash, the relay can be set to communicate
to any upstream or downstream devices
via IEC 61850 GOOSE messaging.
Cable Thermal Model
The cable thermal modelelement protects
feeder cables against overheating due
to excessive load. It estimates the
temperature rise of current carrying
conductors based on the amount of
current flow (I2R) and alarms when
temperature rise exceeds a threshold
value. This protection feature is essential
to ensure the longevity of electrical
feeders; particularly important to prevent
premature cable failures, expensive repair
costs and system down time.
Neutral/Ground Directional
Overcurrent
The directional ground overcurrent isolates
faulted feeders in ring bus or parallel feeder
arrangements. It also allows detection of
back feed of fault current from feeders
with motors.
Control
Cold Load Pick Up
Cold Load Pick up allows automatic or
manual blocking or raising of trip settings
for a period after the breaker has been
closed. This feature adapts the pick up
of overcurrent elements to override the
higher overload currents resulting from
re-energization of feeder after a long
period of time.
Breaker Failure
The Breaker Failure function is used to
determine when a trip command sent to
a breaker has not been executed within
a selectable time delay. In the event of
a breaker failure, the 350 will issue an
additional signal to trip the breakers
connected to the same busbar or signal
the trip of upstream breakers.
Autoreclose
Reclose can be initiated externally or from
an overcurrent protection. Up to four
reclose operations are available, each
with a programmable dead time. For each
reclose shot, the relay can be programmed
to block any overcurrent element.
Automation and
Integration
Inputs & Outputs
The 350 features the following inputs and
outputs for monitoring and control of
typical feeder applications:
• 8contactInputswithprogrammable
thresholds
• 2FormAoutputrelaysforbreakertrip
and close with coil monitoring
• 5FormCoutputrelays
IEC 61850 GOOSE
The 350 supports IEC 61850 Logical Nodes
which allows for digital communications
to DCS, SCADA and higher level control
systems.
In addition, the 350 also supports IEC
61850 GOOSE communication, providing
a means of sharing digital point state
information between 350’s or other IEC
61850 compliant IED’s.
• Eliminatestheneedforhardwiring
contact inputs to contact outputs via
communication messaging.
• Transmitsinformationfromonerelayto
the next in as fast as 8 ms.
• Enablessequencecoordinationwith
upstream and downstream devices.
• WhenBreakerOpenoperation
malfunctions, GOOSE messaging sends
a signal to the upstream breaker to trip
and clear the fault.
Logic Designer
Sixteen logic elements available for applications such as manual control, interlocking, and peer to peer tripping.