GE Power Management
745 Transformer Management Relay
5-91
5 SETPOINTS
5.9 TIME OVERCURRENT CURVES
5
5.9 TIME OVERCURRENT CURVES
5.9.1 NOTE
Graphs of time-current curves on 11”x17” log-log graph paper are available upon request.
5.9.2 ANSI CURVES
The ANSI time overcurrent curve shapes conform to industry standard curves and fit into the ANSI C37.90
curve classifications for extremely, very, normally, and moderately inverse. The 745 ANSI curves are derived
from the following formula:
where:
T
= Operate Time (seconds)
M
= Multiplier setpoint
I
= Input Current
I
pkp
= Pickup Current setpoint
A
,
B
,
C
,
D
,
E
= Constants
Table 5–10: ANSI CURVE CONSTANTS
ANSI CURVE SHAPE
CONSTANTS
A
B
C
D
E
EXTREMELY INVERSE
0.0399
0.2294
0.5000
3.0094
0.7222
VERY INVERSE
0.0615
0.7989
0.3400
–0.2840
4.0505
NORMALLY INVERSE
0.0274
2.2614
0.3000
–4.1899
9.1272
MODERATELY INVERSE
0.1735
0.6791
0.8000
–0.0800
0.1271
NOTE
T
M
A
B
1.03
C
–
----------------------
D
1.03
C
–
(
)
2
-----------------------------
E
1.03
C
–
(
)
3
-----------------------------
+
+
+
, for 1
I
I
pkp
---------
1.03
<
≤
×
M
A
B
I I
pkp
⁄
C
–
-------------------------
D
I I
pkp
⁄
C
–
(
)
2
---------------------------------
E
I I
pkp
⁄
C
–
(
)
3
---------------------------------
+
+
+
, for 1.03
I
I
pkp
---------
20.0
<
≤
×
M
A
B
20.0
C
–
----------------------
D
20.0
C
–
(
)
2
-----------------------------
E
20.0
C
–
(
)
3
-----------------------------
+
+
+
, for
I
I
pkp
---------
20.0
≥
×
=
Содержание 745 TRANSFORMER MANAGEMENT RELAY
Страница 30: ...2 8 745 Transformer Management Relay GE Power Management 2 3 SECURITY 2 GETTING STARTED 2 ...
Страница 150: ...5 100 745 Transformer Management Relay GE Power Management 5 10 INVERSE VOLTS PER HERTZ CURVES 5 SETPOINTS 5 ...
Страница 210: ...7 36 745 Transformer Management Relay GE Power Management 7 2 BLOCK DIAGRAMS 7 SCHEME LOGIC 7 ...
Страница 322: ...9 12 745 Transformer Management Relay GE Power Management 9 3 USING 745PC 9 745 PC SOFTWARE 9 ...
Страница 392: ...11 24 745 Transformer Management Relay GE Power Management 11 1 COMMISSIONING SUMMARY 11 SETPOINT TABLES 11 ...
Страница 396: ...A 4 745 Transformer Management Relay GE Power Management A 1 FIGURES AND TABLES APPENDIXA A ...
Страница 398: ...B 2 745 Transformer Management Relay GE Power Management B 1 EU DECLARATION OF CONFORMITY APPENDIXB B ...
Страница 400: ...C 2 745 Transformer Management Relay GE Power Management C 1 WARRANTY INFORMATION APPENDIXC C ...
Страница 406: ...vi 745 Transformer Management Relay GE Power Management ...
Страница 407: ...GE Power Management 745 Transformer Management Relay NOTES ...