GE Multilin L60, Instruction Manual

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GE Multilin L60 Line Phase Comparison System 8-33
8 THEORY OF OPERATION 8.2 SINGLE-POLE TRIPPING
8
8.2SINGLE-POLE TRIPPING 8.2.1 OVERVIEW
a) INTRODUCTION
Single pole operations make use of many features of the relay. At the minimum, the trip output, recloser, breaker control,
open pole detector, and phase selector must be fully programmed and in service; and either protection elements or digital
inputs representing fault detection must be available for successful operation. When single pole trip-and-reclose is required
overall control within the relay is performed by the trip output element. This element includes interfaces with pilot aided
schemes, the line pickup, breaker control, and breaker failure elements.
Single pole operations are based on use of the phase selector to identify the type of the fault, to eliminate incorrect fault
identification that can be made by distance elements in some circumstances and to provide trip initiation from elements that
are not capable of any fault type identification, such as high-set negative-sequence directional overcurrent element. The
scheme is also designed to make use of the advantages provided by communications channels with multiple-bit capacities
for fault identification.
Figure 8–28: SINGLE-POLE OPERATION
The trip output element receives requests for single and three pole trips and three pole reclose initiation, which it then pro-
cesses to generate outputs that are used to:
• Determine whether a single or three pole operation should be performed.
• Initiate tripping of breaker poles A, B and C, either individually or as a group.
• Initiate breaker failure protection for phases A, B and C, either individually or as a group.
• Notify the open pole detector when a single pole operation is imminent.
• Initiate either single or three pole reclosing.
Block specific protection elements
Protection
elements
Inputs Setting
Setting
Setting
Outputs
Setting
Inputs
Setting
Setting
Line pickup
Reclose request
Force
three-oole
operation
Three-pole
trip
request
Three-pole
trip
Trip
A or B or C
Single-pole
trip
Single-pole
trip request
SLG
faulted
phase
AG
AR FORCE 3-P
Multi-phase
Void
BG
CG
Single-pole
operation
Three-pole
operation
Permission
Reset
Trip
AR Initiate 3-Pole
Pilot-
aided
schemes
Communications
channels
837026A5.CDR
Trip output
Volts
and
amps
Phase selector
Reset
output
Initiate breaker
failure
Breaker
control
Breaker
1 and 2
pole state
Breaker
1 and 2
out-of-service
Volts
and
amps
Recloser
CL
OSE
1
CL
OSE
1
CL
OSE
2
CL
OSE
2
Operator
Setting
Setting
Inputs
Outputs
Initiate
Initiate
Multi-phase
Fault locator
Open
pole
detector
Setting
Br
eak
er
1
and
2