Procedure two, Data, Tap and phase shift settings – Basler Electric BE1-87T User Manual
Page 84: Procedure two -42
4-42
BE1-87T Installation
9171300990 Rev V
Procedure Two
Refer to Figure 4-37 for a one-line drawing of this example.
Data
Figure 4-38. Two Winding Transformer Relay Setting Calculation Example
Specifications
High side
Low side
kV
69
12.47
MVA
12/20
12/20
CT Ratio
600
1200
CT Tap
300
800
CT Accuracy Class
400
800
CT Resistance (ohms)
0.18
0.48
One-Way Lead Burden
(ohms)
0.7
0.7
XFMR Connection*
DELTA
WYE
CT Connection
WYE
WYE
Input #
1
2
Fault Current (Three-
Phase)
1,916
10,603
Fault Current (Single-
Phase)
1,171
11,231
*
Standard connection: High voltage leads low voltage by 30°.
Step 1. Determine the full load primary current (I
P
) of each winding:
Tap and Phase Shift Settings
Use the top kVA rating of the transformer when making the calculations:
HIGH
LOW
IP =
×
MVA rating of transformer
1,000
V
3
LINE - LINE
(
)(
)
(
)
(
)
IP
IP
=
=
20,000
69
167.35
3
I
I
P
P
=
=
20,000
12
3
925
.47
.98