Line - GE UR Series Instruction Manual

5.3 SYSTEM SETUP
2.
Charging current compensation calculations should be performed for an arrangement where the VTs are connected
to the line side of the circuit; otherwise, opening the breaker at one end of the line will cause a calculation error.
NOTE
Differential current is significantly decreased when the
the proper reactance values are entered. The effect of charging current compensation can be viewed in the
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NOTE
ING 87L DIFFERENTIAL CURRENT
ZERO-SEQUENCE CURRENT REMOVAL:
This setting facilitates application of the L90 to transmission lines with tapped transformer(s) without current measurement
at the tap(s). If the tapped transformer is connected in a grounded wye on the line side, it becomes a source of the zero-
sequence current for external ground faults. As the transformer current is not measured by the L90 protection system, the
zero-sequence current would create a spurious differential signal and may cause a false trip.
This setting, if enabled, forces the L90 relays to remove the zero-sequence current from the phase currents prior to forming
their differential signals. This ensures stability of the L90 protection on external ground faults. Removal of the zero-
sequence current may, however, cause the relays to trip all three phases for internal ground faults. Consequently, a phase
selective operation of the L90 system is not retained if the setting is enabled. This does not impose any limitation, as single-
pole tripping is not recommended for lines with tapped transformers.
Refer to the APPLICATION OF SETTINGS chapter for more setting guidelines.
LOCAL (TERMINAL 1 and TERMINAL 2) ID NUMBER:
In installations using multiplexers or modems for communication, it is desirable to ensure the data used by the relays pro-
tecting a given line comes from the correct relays. The L90 performs this check by reading the ID number contained in the
5
messages sent by transmitting relays and comparing this ID to the programmed correct ID numbers by the receiving relays.
This check is used to block the differential element of a relay, if the channel is inadvertently set to Loopback mode, by rec-
ognizing its own ID on a received channel. If an incorrect ID is found on a either channel during normal operation, the Flex-
Logic™ operand 87 CH1(2) ID FAIL is set, driving the event with the same name. The result of channel identification is also
available in
ACTUAL VALUES
purposes. The default value "0" at local relay ID setting indicates that the channel ID number is not to be checked. Refer to
the CURRENT DIFFERENTIAL section in this chapter for additional information.
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PATH: SETTINGS SYSTEM SETUP
„

LINE

„
These settings specify the characteristics of the line. The line impedance value should be entered as secondary ohms.
This data is used for fault location calculations. See the
the Source and Trigger for fault calculations.
5-30
X
For 3 terminal line: =
react
actual values menu. This effect is very dependent on CT and VT accuracy.
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STATUS CHANNEL TESTS
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LINE
POS SEQ IMPEDANCE
MAGNITUDE:
POS SEQ IMPEDANCE
MESSAGE
ANGLE: 75°
ZERO SEQ IMPEDANCE
MESSAGE
MAGNITUDE:
ZERO SEQ IMPEDANCE
MESSAGE
ANGLE: 75°
LINE LENGTH UNITS:
MESSAGE
km
LINE LENGTH (km
MESSAGE
100.0
L90 Line Differential Relay

1 1
⁄
1 ---------------------------------- - + ---------------------------------- -

X X
react_terminal1 react_terminal2
CHARGING CURRENT COMPENSATION
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VALIDITY OF CHANNEL CONFIGURATION
Range: 0.01 to 250.00 Ω in steps of 0.01
3.00 Ω
Range: 25 to 90° in steps of 1
Range: 0.01 to 650.00 Ω in steps of 0.01
9.00 Ω
Range: 25 to 90° in steps of 1°
Range: km, miles
Range: 0.0 to 2000.0 in steps of 0.1
):
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SETTINGS PRODUCT SETUP
5 SETTINGS

1
+ ---------------------------------- -

X
react_terminal3
setting is "Enabled" and
for commissioning
5.3.5 LINE
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menu for assigning
FAULT REPORT
GE Power Management
METER-