Basler Electric BE1-87T - Manual (Page 99)

9171300990 Rev V BE1-87T Test Procedures 5-3
Example One:
Assume:
tap tap slope
1 2
2 38 15% = = = , . ,
Inputs I A pu
I
T
pu
I A pu
I
T
pu
: ( )
. ( )
.
.
1
1
1
2
2
2
2 1
2
2
1
38 1
38
38
1
= = =

 

= = =

 

Check:
Therefore: Use Equation 2 or 2a.
From Figure 1-2 (the percentage restraint characteristic of the BE1-87T at 15% slope), the minimum
current where trip occurs is:
In terms of current, the trip current is:
Using Equation 2a:
I
trip 1
2 38
38
0 35
2 7
= +

 

=
.
.
.
. A
Example Two:
Assume:
tap tap slope
1 2
2 38 15% = = = , . ,
Inputs I A pu
I
T
pu
I A pu
I
T
pu
: ( )
. ( )
.
.
1
1
1
2
2
2
6 3
6
2
3
114 3
114
38
3
= = =

 

= = =

 

I balance
slope
slope
1
0.35
100
1
100
< >
−
(in pu)
< 1 1.983
( )
( )
1 < >
0.35
0.15
1 - 0.15
( )
I
trip 1 = 1 pu + 0.35
= 1.35 pu
I tap
trip 1
(2 0)
2 70
= x
= ± ±
1.35 pu
= (1.35)
A 6% 100 mA
.
.