Siemens 7SK80 Manual page 392

Technical Data
4.15 Ground Fault Detection (Sensitive/Insensitive)
Ground Fault Pickup for All Types of Ground Faults (Inverse Time Characteristic)
User-defined characteristic (defined by a maximum of 20 value pairs of current and time delay in direction
measurement method "cos phi and sin phi")
Pickup current 51Ns
for sensitive 1 A transformer
for sensitive 5 A transformer
for normal 1 A transformer
for normal 5-A transformer
Time multiplier T
Pickup threshold
Dropout ratio
Measurement tolerance
sensitive
non-sensitive
Operating time tolerance in linear range
Influencing Variables
Auxiliary DC voltage in range
0,8 ≤ V
/V
Aux AuxNom
Temperature in range
–5 °C (41 °F) ≤ Θ
Frequency in range of 25 Hz – 70 Hz
Frequency in range of 0.95 ≤ f/f
or 60 Hz)
Frequency outside range 0.95 ≤ f/f
Harmonics
- up to 10 % 3rd harmonic
- up to 10 % 5th harmonic
Note: When using the sensitive transformer, the linear range of the measuring input for sensitive ground fault
detection is from 0.001 A to 1.6 A or 0.005 A to 8.0 A, depending on parameter 205 CT SECONDARY. The
function is however still preserved for larger currents.
392
51Ns
≤ 1.15
≤ 55 °C (131 °F)
amb
≤ 1.05 (f
Nom
≤ 1.05
Nom
0.001 A to 1.400 A
0.005 A to 7.000 A
0.05 A to 4.00 A
0.25 A to 20.00 A
0.10 s to 4.00 s or ∞ (disabled)
Approx. 1.10 · I
51Ns
Approx. 1.05 · I
51Ns
3 % of setting value or 1 mA at I
5 A
for setting values < 10 mA approx. 20 %
3 % of setting value or 15 mA for I
= 5 A
7 % of reference (calculated) value for 2 ≤ I/I
current tolerance, or 70 ms
1 %
0.5 %/10 K
= 50 Hz 1 %
Nom
Increased tolerances
1 %
1 %
E50417-G1140-C344-A5, Release date 11.2012
Increments
0.001 A
Increments
0.005 A
Increments
0.01 A
Increments
0.05 A
Increments 0.01
s
for I > 50 mA
51Ns
= 1 A or 5 mA at I
Nom
= 1 A or 75 mA for I
Nom
51Ns
SIPROTEC, 7SK80, Manual
=
Nom
Nom
≤ 20 + 2 %