Specifications

7SR242 Duobias Performance Specification
©2010 Siemens Protection Devices Limited Chapter 3 - Page 40 of 45
Operate and Reset Level
Attribute Value
Operate level
2
nd
Bias Slope Type = Line
B)I(forIMI
andIMI
andII
RESTRAINRESTRAIN2OPERATE
RESTRAIN1OPERATE
SETTING INITIAL 87OPERATE
!u!
u!
!
Where
2
II
I
III
21
RESTRAIN
21OPERATE


B = 87BD 1
st
Bias slope limit
M
1
= 87BD 1
st
Bias slope
M
2
= 87BD 2nd Bias slope
I
OP
Operate level
2
nd
Bias Slope Type = Curve
B)I(for
2
KI
I
andIMI
andII
RESTRAIN
22
RESTRAIN
OPERATE
RESTRAIN1OPERATE
SETTING INITIAL 87OPERATE
!

!
u!
!
Where
K
2
= B
2
– 2M
1
2
B
2
87BD Initial Setting
r 5% of setting or r 0.01In
87BD Bias Slope
r 10% of bias slope setting
Reset level  90% of I
OP
Repeatability
r 2%
Transient overreach  5%
-10 °C to +55 °C
Variation
f
nom
- 3 Hz to f
nom
+ 2 Hz
2.15.2 Operate Time
Attribute Value
0 to 3 x I
OP
, 35 ms, r 10ms
t
basic
Element basic operate time
(Inrush Action: Enabled)
0 to 10 x I
OP
, 30 ms, r 10ms
t
op
Operate time following delay
t
basic
+ t
d
, r 1% or r 10ms