Technical Data
4.5 Ground Fault Differential Protection in Resonant-grounded / Isolated Systems
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
300
4.5
Ground Fault Differential Protection in Resonant-grounded /
Isolated Systems
Pickup Values
Operating Times
Time Delays
Frequency Operating Range
Differential current;
87N L: IN(s)>
I
Nom
= 1 A
0.003 A to 1.000 A
Increments 0.001 A
The operating times depend on the communication speed. The following data require a transmission rate of 512 kbit/s.
Pickup/trip times of the 87N L: IN(s)> element at 50 Hz
or 60 Hz approx.
minimum 24 ms
to
29 ms
Dropout times of the I87N L: I-DIFF> element approx.
minimum
35 ms to 50 ms
Minimum current for direction determination
5 % of setting value or 1 %
I
Nom
Delay of the 87N L: I-DIFF> element approx.
1 % of setting value or 10 ms
Frequency range
45 Hz to 55 Hz at 50 Hz
55 Hz to 65 Hz at 60 Hz
25 Hz to 45 Hz at 50 Hz
30 Hz to 55 Hz at 60 Hz
Increased tolerances
Tripping delay
87N L:TripDelay
0.00 s to 320 s
Increments 0.01 s
Expiry tolerances
1 % of setting value or 10 ms
The set times are pure time delays.
Operating Range
0.8
≤
f/f
N
≤
1.2
stable at machine start-up (f = 0 to f
N
)
