8-14
C70 Capacitor Bank Protection and Control System
GE Multilin
8.1 OVERVIEW
8 THEORY OF OPERATION
8
(EQ 8.56)
In the above equations,
I
base
represents the differential CT primary current rating, inserted here to put the string currents on
the same per-unit base used by the relay. Voltages are in primary volts, capacitances in Farads, and frequency in radians
per second.
The two neutral currents can be derived from the above equations:
(EQ 8.57)
The differential current is the vector difference between the two currents. By subtracting
I
N
2
from
I
N
1
, one obtains:
(EQ 8.58)
At the same time the total currents in each phase are driven by the total admittance of the two banks in each phase:
(EQ 8.59)
Inserting the equations above into equation 8.58 so as to eliminate the voltages:
(EQ 8.60)
Label
k
A
,
k
B
, and
k
C
as follows:
(EQ 8.61)
Also, convert from phase coordinates into sequence components as follows, and equation 8.60 becomes:
(EQ 8.62)
Substituting this into equation 8.54, we get:
I
A
1
V
A
j
ω
C
A
1
×
I
base
------------------------------
I
A
2
;
V
A
j
ω
C
A
2
×
I
base
------------------------------
=
=
I
B
1
V
B
j
ω
C
B
1
×
I
base
------------------------------
I
B
2
;
V
B
j
ω
C
B
2
×
I
base
------------------------------
=
=
I
C
1
V
C
j
ω
C
C
1
×
I
base
------------------------------
I
C
2
;
V
C
j
ω
C
C
2
×
I
base
------------------------------
=
=
I
N
1
I
A
1
I
B
1
I
C
1
+
+
j
ω
C
A
1
V
A
j
ω
C
B
1
V
B
j
ω
C
C
1
V
C
+
+
I
base
-------------------------------------------------------------------------------------
=
=
I
N
2
I
A
2
I
B
2
I
C
2
+
+
j
ω
C
A
2
V
A
j
ω
C
B
2
V
B
j
ω
C
C
2
V
C
+
+
I
base
-------------------------------------------------------------------------------------
=
=
I
DIF
I
N
1
I
N
2
–
=
j
ω
V
A
C
A
1
C
A
2
–
(
)
V
B
C
B
1
C
B
2
–
(
)
V
C
C
C
1
C
C
2
–
(
)
+
+
[
]
I
base
----------------------------------------------------------------------------------------------------------------------------------------------
=
I
A
I
A
1
I
A
2
+
j
ω
V
A
C
A
1
C
A
2
+
(
)
I
base
---------------------------------------------
=
=
I
B
I
B
1
I
B
2
+
j
ω
V
B
C
B
1
C
B
2
+
(
)
I
base
---------------------------------------------
=
=
I
C
I
C
1
I
C
2
+
j
ω
V
C
C
C
1
C
C
2
+
(
)
I
base
----------------------------------------------
=
=
I
DIF
j
ω
V
A
C
A
1
C
A
2
–
(
)
V
B
C
B
1
C
B
2
–
(
)
V
C
C
C
1
C
C
2
–
(
)
+
+
[
]
I
base
----------------------------------------------------------------------------------------------------------------------------------------------
=
I
A
C
A
1
C
A
2
–
C
A
1
C
A
2
+
---------------------------
I
B
C
B
1
C
B
2
–
C
B
1
C
B
2
+
---------------------------
×
I
C
C
C
1
C
C
2
–
C
C
1
C
C
2
+
---------------------------
×
+
+
×
=
k
A
C
A
1
C
A
2
–
C
A
1
C
A
2
+
---------------------------
k
B
,
C
B
1
C
B
2
–
C
B
1
C
B
2
+
---------------------------
k
C
,
C
C
1
C
C
2
–
C
C
1
C
C
2
+
---------------------------
=
=
=
I
DIF
k
A
I
1
I
2
I
0
+
+
(
)
k
B
a
ˆ
2
I
1
a
ˆ
I
2
I
0
+
+
(
)
k
C
a
ˆ
I
1
a
ˆ
2
I
2
I
0
+
+
(
)
+
+
=
I
1
k
A
a
ˆ
2
k
B
a
ˆ
k
C
+
+
(
)
I
2
k
A
a
ˆ
k
B
a
ˆ
2
k
C
+
+
(
)
I
0
k
A
k
B
k
C
+
+
(
)
+
+
=
Содержание C70
Страница 10: ...x C70 Capacitor Bank Protection and Control System GE Multilin TABLE OF CONTENTS ...
Страница 30: ...1 20 C70 Capacitor Bank Protection and Control System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Страница 394: ...5 270 C70 Capacitor Bank Protection and Control System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Страница 452: ...8 18 C70 Capacitor Bank Protection and Control System GE Multilin 8 1 OVERVIEW 8 THEORY OF OPERATION 8 ...
Страница 474: ...9 22 C70 Capacitor Bank Protection and Control System GE Multilin 9 4 SETTING EXAMPLE 9 APPLICATION OF SETTINGS 9 ...
Страница 486: ...10 12 C70 Capacitor Bank Protection and Control System GE Multilin 10 6 DISPOSAL 10 MAINTENANCE 10 ...
Страница 630: ...B 110 C70 Capacitor Bank Protection and Control System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Страница 676: ...E 10 C70 Capacitor Bank Protection and Control System GE Multilin E 1 OVERVIEW APPENDIX E E ...
Страница 688: ...F 12 C70 Capacitor Bank Protection and Control System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...
Страница 698: ...H 8 C70 Capacitor Bank Protection and Control System GE Multilin H 3 WARRANTY APPENDIX H H ...