Siemens 7SR242 - Figure 3-2 Functional Diagram for Biased Current Differential Protection

7SR242 Duobias Description Of Operation
©2010 Siemens Protection Devices Limited Chapter 1 Page 22 of 52
c
Pickup
trip
1
1
General Pickup
87BD
87BD 1
st
Bias Slope Limit
c
87BD 1
st
Bias Slope
87BD Initial
W1-IL1
W1-IL2
W1-IL3
&
Inhibit 87BD
87BD Element
Enabled
Disabled
c
Pickup
trip
c
Pickup
trip
ICT
W1 ICT Multiplier
W1 ICT Connection
W2-IL1
W2-IL2
W2-IL3
ICT
W2 ICT Multiplier
W2 ICT Connection
87BD Delay
87BD 2
nd
Bias Slope
87BD 2
nd
Bias Slope Type
81HBL2 Element
Enabled
Disabled
Wn-IL1
Wn-IL2
Wn-IL3
81HBL2 Bias
L2 81HBL2
81HBL2 Setting
c
>
>
>
L1 81HBL2
L3 81HBL2
81HBL5 Element
Enabled
Disabled
Wn-IL1
Wn-IL2
Wn-IL3
81HBL5 Bias
81HBL5 Setting
c
>
>
>
87BD Inrush Action
Off
Inhibit
&
&
&
A
B
C
87BD ‘A’ Inhibit
87BD ‘B’ Inhibit
87BD ‘C’ Inhibit
87BD ‘A’
Inhibit
87BD ‘B’
Inhibit
87BD ‘C’
Inhibit
L2 81HBL5
L1 81HBL5
L3 81HBL5
87BD Overfluxing Action
Off
Inhibit
&
&
&
87BD ‘A’ Inhibit
87BD ‘B’ Inhibit
87BD ‘C’ Inhibit
Figure 3-2 Functional Diagram for Biased Current Differential Protection