GE L90 Instruction Manual page 186

5.2 PRODUCT SETUP
The L90 incorporates a multi-ended fault locator method based on the synchronized voltage and current measurements at
all ends of the transmission line. This makes it possible to compute the fault location without assumptions or approxima-
tions. This fault locator method is applicable on both two-terminal and three-terminal applications, with results computed
independently at each terminal. For three-terminal line applications, the fault locator is reports the exact line segment at
which the fault occurred and the distance to the fault from the terminal adjacent to the fault.
if charging current compensation is configured and enabled, the line charging current is removed at each terminal for
improved accuracy.
During communication channel failures, the L90 uses the single-ended algorithm to calculate and report fault location.
When the single-ended algorithm is used for three-terminal line applications, the faulted segment of the line is not deter-
mined and reported.
The L90 relay supports one fault report and an associated fault locator. The signal source and trigger condition, as well as
the characteristics of the line or feeder, are entered in this menu.
The fault report stores data, in non-volatile memory, pertinent to an event when triggered. The captured data contained in
5
the FaultReport.txt file includes:
• Fault report number.
• Name of the relay, programmed by the user.
• Firmware revision of the relay.
• Date and time of trigger.
• Name of trigger (specific operand).
• Line or feeder ID via the name of a configured signal source.
• Active setting group at the time of trigger.
• Pre-fault current and voltage phasors (two cycles before either a 50DD disturbance associated with fault report source
or the trigger operate). Once a disturbance is detected, pre-fault phasors hold for 3 seconds waiting for the fault report
trigger. If trigger does not occur within this time, the values are cleared to prepare for the next disturbance.
• Fault current and voltage phasors (one cycle after the trigger).
• Elements operated at the time of triggering.
• Events: 9 before trigger and 7 after trigger (only available via the relay webpage).
• Fault duration times for each breaker (created by the breaker arcing current feature).
The captured data also includes the fault type and the distance to the fault location, as well as the reclose shot number
(when applicable) To include fault duration times in the fault report, the user must enable and configure breaker arcing cur-
rent feature for each of the breakers. Fault duration is reported on a per-phase basis.
The relay allows locating faults, including ground faults, from delta-connected VTs. In this case, the missing zero-sequence
voltage is substituted either by the externally provided neutral voltage (broken delta VT) connected to the auxiliary voltage
channel of a VT bank, or by the zero-sequence voltage approximated as a voltage drop developed by the zero-sequence
current, and user-provided zero-sequence equivalent impedance of the system behind the relay.
The trigger can be any FlexLogic™ operand, but in most applications it is expected to be the same operand, usually a vir-
tual output, that is used to drive an output relay to trip a breaker. To prevent the overwriting of fault events, the disturbance
detector should not be used to trigger a fault report. A
triggered.
5-40
FAULT REP 1 REM2-TAP
MESSAGE
LENGTH (km ): 100.0
FAULT REPORT 1 VT
MESSAGE
SUBSTITUTION: None
FAULT REP 1 SYSTEM
MESSAGE
Z0 MAG: 2.00
FAULT REP 1 SYSTEM
MESSAGE
Z0 ANGLE: 75°
L90 Line Current Differential System
Range: 0.0 to 2000.0 in steps of 0.1
Range: None, I0, V0
Range: 0.01 to 650.00 ohms in steps of 0.01
Range: 25 to 90° in steps of 1
event is automatically created when the report is
FAULT RPT TRIG
5 SETTINGS
GE Multilin