Inverse-Time Overcurrent Protection (51 And 51N Elements) - Siemens SIPROTEC 7SJ62 Instruction Manual

Technical Data
10.3

Inverse-Time Overcurrent Protection (51 and 51N Elements)

Pickup and Time
Multiplier Ranges/
Resolutions
Trip Time Charac-
teristics As Per IEC
Tolerances
Influencing Vari-
ables for Pickup
10-12
Pickup Current
Time Multipliers for
I , I IEC–Characteristics
p Ep,
Time Multiplier for 51, 51N
ANSI characteristics
As per IEC 60255-3, Section 3.5.2 or BS 142 (See also Figure 10-1)
1250$/ ,19(56( (Type A)
9(5< ,19(5(6( (Type B)
(;75(0(/< ,19 (Type C)
/21* ,19(56( (Type B)
≥ 20 are identical to those for I/I
The trip times for I/I
p
Pickup threshold
Dropout threshold
Pickup Currents I , I
p Ep
Trip Time for 2 ≤ I/I ≤ 20
p
Power supply direct voltage in range
0.8 ≤ V ≤ 1.15
/ V
PS PS nominal
Temperature in range
23º F ≤ ϑ ≤ 131º F
amb
Frequency in range
0.95 ≤ f/f ≤ 1.05
N
Harmonic currents
– Up to 10 % 3. Harmonic
– Up to 10 % 5. Harmonic
1
) For I = 1 A, divide all limits and increments by 5.
N
51, 51N 0.50 A to 20.00 A
T , T 0.05 s to 3.20 s
p Ep
or ∞ (delay does not expire)
D 0.05 s to 15.00 s
or ∞ (delay does not expire)
t --------------------------------- - T
=
( ⁄
I I
13.5
t -------------------------- - T
=
( ⁄
I I
p
80
t = -------------------------- - T
( ⁄
I I
p
120
t -------------------------- - T
=
( ⁄
I I
p
For All Characteristics
t trip time in seconds
T setting value of the time multiplier
p
I fault current
setting value of the pickup current
I
p
approx. 1.10 · I
approx. 1.05 · I
2 % of setting value, or 50 mA
5 % of reference (calculated) value + 2 %
current tolerance, respectively 30 ms
1 %
0.06% /10º F
1 %
1 %
1 %
1
) (Increments 0.05 A)
(Increments 0.01 s)
(Increments 0.01 s)
0.14
⋅
[s]
p
0.02
)
– 1
p
⋅
[s]
p
1
)
1
–
⋅
[s]
p
2
)
– 1
⋅
[s]
p
1
)
1
–
= 20.
p
p
≥ 0.3
for I /I
p p N
1
)
7SJ62 Manual
C53000-G1140-C121-1
1
)