Technical Data
4.3 87 Differential Protection Phase Comparison Protection
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
296
4.3
87 Differential Protection Phase Comparison Protection
Pickup Values
Operating Times
Time Delaytime delays
Emergency Operation
Frequency Operating Range
Differential current, dynamic;
87L Idyn>
I
Nom
= 1 A
0.20 A to 4.00 A
Increments 0.01 A
I
Nom
= 5 A
1.00 A to 20.00 A
Differential current when switching onto a fault;
87L Idyn close>
I
Nom
= 1 A
0.20 A to 4.00 A
Increments 0.01 A
I
Nom
= 5 A
1.00 A to 20.00 A
Differential current, static;
87L Isteady>
I
Nom
= 1 A
0.50 A to 4.00 A
Increments 0.01 A
I
Nom
= 5 A
2.50 A to 20.00 A
The operating times depend on the communication speed. The following data require a transmission rate of 512 kbit/s.
Pickup time with infeed at both ends approx.
15 ms to 40 ms
Pickup times with infeed at both ends approx.
35 ms to 40 ms
Command time approx.
15 ms to 90 ms
Start time at 50 Hz. approx.
51 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
if only the static element is active
Tolerances
I
Nom
= 1 A
20 mA
I
Nom
= 5 A
100 mA
Tripping delay
87L Trip Delay
0.00 s to 0.10 s
Increments 0.01 s
Expiry tolerances
1 % of set value or 10 ms
The set times are pure time delays.
Communication failure
See section „Time Overcurrent Protection“
Operating Range
0.8
≤
f/f
N
≤
1.2
stable when starting machine
