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

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