Single-Pole Tripping; Overview - GE L60 Instruction Manual

8 THEORY OF OPERATION

8.2SINGLE-POLE TRIPPING

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.
Volts
and
amps
Protection
Setting
elements
Inputs Setting
Pilot-
aided
schemes
Setting Setting
Inputs Outputs
Communications
channels
AG
BG
CG
Setting
Line pickup
Multi-phase
Void
Setting
AR FORCE 3-P
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.
GE Multilin
Phase selector
Reset
output
Block specific protection elements
Trip output
Single-pole
Single-pole
trip request
trip
Trip
A or B or C
Single-pole
operation
SLG
faulted
phase
Permission
Reset
Three-pole Three-pole
trip trip
request
Force Three-pole
three-oole operation
operation
Trip
Reclose request
AR Initiate 3-Pole
Figure 8–28: SINGLE-POLE OPERATION
L60 Line Phase Comparison System
8.2 SINGLE-POLE TRIPPING
Fault locator
Volts
and
amps
Open
pole
detector
Initiate breaker
failure
Breaker Breaker
1 and 2 1 and 2
pole state out-of-service
Breaker
control
Setting
Operator
Setting
Initiate
Initiate
Recloser
Multi-phase

8.2.1 OVERVIEW

Inputs
Outputs
8
837026A5.CDR
8-33