•
For delta-co
V
BG
is a function of
of positive-sequence to zero-sequence currents, but may be
Neglecting
R
R
, use R
L
from Figure D-1:
HIGH LOW
NOTE
nnected
the proportion
approximated by the same equation as fo
CTs:
r wye connected CTs (for worst case).
V
7
37
6
0
57
0
7
29
V
BG
.
.
.
.
V
.
.
*
.
.
1
54
6
0
47
0
6
50
V
BG
Since a phase-to-ground fault looks like a phase-to-phase fault on the delta side
of a delta/wye transformer, each CT has to carry only one times the one way
lead burden.
Step 4. Determine the effective CT accuracy class (V
CE
):
Step 5.
VB is the largest of the burden voltages calculated in Steps 2 and 3.
HIGH
LOW
TERTIARY
D-4
BE1-CDS240 Settings Calculations
9365200990 Rev F
Determine the saturation factor (SF):
135
0
400
SF
.
1
54
.
116
0
300
SF
.
7
34
.
144
0
320
SF
.
2
64
.
NOTE
Maximum Recommended
SF
= 0.5. Larger saturation factors will make the relay insecure
for external faults, especially during high DC offset conditions. Possible solutions are to
increase the CT quality, adjust the CT tap connections to increase effective accuracy
class and lower CT currents or to use internal phase compensation instead of delta
connecting CTs.
HIGH
LOW
TERTIARY
135
0
400
1
54
SF
.
.
116
0
300
7
34
SF
.
.
144
0
320
2
64
SF
.
.
CE
B
V
V
SF
M
TAP
MAX
N
N
)
CTR
CLASS
C
USED
CE
V
CTR
V
Accuracy)(
(Base
AX
Summary of Contents for BE1-CDS240
Page 2: ......
Page 8: ...vi BE1 CDS240 Introduction 9365200990 Rev F This page intentionally left blank ...
Page 38: ...1 28 BE1 CDS240 General Information 9365200990 Rev F This page intentionally left blank ...
Page 40: ...ii BE1 CDS240 Quick Start 9365200990 Rev F This page intentionally left blank ...
Page 152: ...ii BE1 CDS240 Metering 9365200990 Rev F This page intentionally left blank ...
Page 226: ...iv BE1 CDS240 Application 9365200990 Rev F This page intentionally left blank ...
Page 286: ...ii BE1 CDS240 Security 9365200990 Rev F This page intentionally left blank ...
Page 290: ...9 4 BE1 CDS240 Security 9365200990 Rev F This page intentionally left blank ...
Page 292: ...ii BE1 CDS240 Human Machine Interface 9365200990 Rev F This page intentionally left blank ...
Page 306: ...10 14 BE1 CDS240 Human Machine Interface 9365200990 Rev F This page intentionally left blank ...
Page 308: ...ii BE1 CDS240 ASCII Command Interface 9365200990 Rev F This page intentionally left blank ...
Page 342: ...11 34 BE1 CDS240 ASCII Command Interface 9365200990 Rev F This page intentionally left blank ...
Page 349: ...Figure 12 5 Horizontal Rack Mount Front View 9365200990 Rev F BE1 CDS240 Installation 12 5 ...
Page 361: ...Figure 12 17 Typical DC Connection Diagrams 9365200990 Rev F BE1 CDS240 Installation 12 17 ...
Page 372: ...12 28 BE1 CDS240 Installation 9365200990 Rev F This page intentionally left blank ...
Page 468: ...13 92 BE1 CDS240 Testing and Maintenance 9365200990 Rev F This page intentionally left blank ...
Page 512: ...14 42 BE1 CDS240 BESTCOMS Software 9365200990 Rev F This page intentionally left blank ...
Page 544: ...ii BE1 CDS240 Terminal Communication 9365200990 Rev F This page intentionally left blank ...
Page 550: ...ii BE1 CDS240 Settings Calculations 9365200990 Rev F This page intentionally left blank ...
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