CHAPTER 2: PRODUCT DESCRIPTION SPECIFICATIONS
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 2-33
2
Pickup: 0.050 to 30.000 pu in steps of 0.001
Dropout: 97 to 98%
Memory duration: 5 to 25 cycles in steps of 1
Voltage supervision pickup (series compensation applications):
0 to 5.000 pu in steps of 0.001
GROUND DISTANCE OPERATING TIME CURVES
The operating times are response times of a microprocessor part of the relay. See output contacts specifications for estimation of the
total response time for a particular application. The operating times are average times including variables such as fault inception angle
or type of a voltage source (magnetic VTs and CVTs). The figure shows zone 1 ground distance time curves for a 60 Hz system at nominal
system frequency.
LINE PICKUP
Phase instantaneous overcurrent: 0.020 to 30.000 pu
Undervoltage pickup: 0.004 to 3.000 pu
Overvoltage delay: 0.000 to 65.535 s
LINE CURRENT DIFFERENTIAL (87L)
Application: 2 or 3 terminal line, series compensated line, tapped line, with charging current compensation
Characteristic: Dual slope percent differential
Pickup current level: 0.20 to 4.00 pu in steps of 0.01
CT Tap (CT mismatch factor): 0.20 to 5.00 in steps of 0.01
Slope # 1: 1 to 50%
Slope # 2: 1 to 70%
Level accuracy: ±3% of reading of the maximum circuit current
Breakpoint between slopes: 0.0 to 20.0 pu in steps of 0.1
DTT: Direct Transfer Trip (1 and 3 pole) to remote L90
Operating Time: 1.0 to 1.5 power cycles duration
Asymmetrical channel delay compensation using GPS:
asymmetry up to 10 ms
In-zone transformer group compensation: 0 to 330° in steps of 30°
Inrush inhibit level: 1.0 to 40.0%f
0
in steps of 0.1
Inrush inhibit mode: per-phase, 2-out-of-3, average
Zero-sequence current differential (87LG):
87LG pickup level: 0.05 to 1.00 pu in steps of 0.01
87LG slope: 1 to 50%
87LG pickup delay: 0.00 to 5.00 s in steps of 0.01
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