GE UR Series Instruction Manual page 207

5 SETTINGS
c) 87L TRIP
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PATH: SETTINGS GROUPED ELEMENTS
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87L TRIP
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The 87L Trip element must be used to secure the generation of tripping outputs. It is especially recommended for use in all
single-pole tripping applications. It provides the user with the capability of maintaining the trip signal while the fault current
is still flowing, to choose single-pole or three-pole tripping, to employ the received Direct Transfer Trip signals, to assign
supervising trip elements like 50DD, etc. The logic is used to ensure that the relay will:
• trip the faulted phase for a single line to ground fault, as detected by the line differential element
• trip all three phases for any internal multiphase fault
• trip all three phases for a second single line to ground fault during or following a single pole trip cycle
For maximum security, it is recommended the Disturbance Detector (plus other elements if required) be assigned to see a
change in system status before a trip output is permitted. This ensures the relay will not issue a trip signal as a result of
incorrect settings, incorrect manipulations with a relay, or inter-relay communications problems (for example, extremely
noisy channels). The Open Pole Detector provides forcing of three-pole tripping for Sequential faults and Close onto Fault
if desired. The Open Pole Detector feature must be employed and adequately programmed for proper operation of this fea-
ture.
If DTT is not required to cause the 87L Trip scheme to operate, it should be disabled at the remote relay via the
CURRENT DIFFERENTIAL
NOTE
87L TRIP FUNCTION:
This setting is used to enable/disable the element.
87L TRIP SOURCE:
This setting is used to assign a source for seal-in function.
87L TRIP MODE:
This setting is used to select either three-pole or single-pole mode of operation.
87L TRIP SUPV:
This setting is used to assign a trip supervising element. FlexLogic™ operand 50DD SV is recommended (the element has
to be enabled); otherwise elements like IOC, Distance, etc. can be used.
GE Power Management
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SUPERVISING ELEMENTS
87L TRIP FUNCTION:
Disabled
87L TRIP SOURCE:
SRC 1
87L TRIP MODE:
3-Pole
87L TRIP SUPV:
Off
87L TRIP FORCE 3-φ:
Off
87L TRIP SEAL-IN:
Disabled
87L TRIP SEAL-IN
PICKUP: 0.20 pu
87L TRIP TARGET:
Self-reset
87L TRIP EVENTS:
Disabled
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menu (see
SETTINGS CONTROL ELEMENTS
L90 Line Differential Relay
5.5 GROUPED ELEMENTS
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87L TRIP
Range: Disabled, Enabled
Range: SRC 1, SRC 2,..., SRC 6
Range: 3-Pole, 1-Pole
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: Disabled, Enabled
Range: 0.20 to 0.80 pu in steps of 0.01
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
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LINE DIFFERENTIAL ELEMENTS
5
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