Rockwell Automation 865 Differential Protection Relay User Manual
Page 88
Advertising
3-44 Protection
Functions
865-UM001A-EN-P – July 2009
Equation 10 – RXIDG
pickup
RXIDG
I
k
I
t
ln
35
.
1
8
.
5 −
=
t
=
Operation delay in seconds
k = User’s
multiplier
I = Measured
value
I
pickup
=
User’s pick up setting
Example for Delay type RI :
k = 0.50
I = 4
pu
I
pickup
=
2
pu
3
.
2
2
4
236
.
0
339
.
0
5
.
0
=
⎟
⎠
⎞
⎜
⎝
⎛
−
=
RI
t
The operation time in this example will be 2.3 seconds. The same result
can be read from Figure 3.30.
Example for Delay type RXIDG:
k = 0.50
I = 4
pu
I
pickup
=
2
pu
9
.
3
2
5
.
0
4
ln
35
.
1
8
.
5
=
⋅
−
=
RXIDG
t
The operation time in this example will be 3.9 seconds. The same result
can be read from Figure 3.31.
Advertising