GE Multilin
C70 Capacitor Bank Protection and Control System
10-13
10 APPLICATION OF SETTINGS
10.4 SETTING EXAMPLE
10
•
The type 8L CT/VT module U1 to U3 three-phase CT channels are connected to the neutral side window CTs with a
50 / 5 A ratio.
The following settings are applied in the EnerVista UR Setup software.
The VT channels are connected as follows.
•
The type 8L CT/VT module F5 to F7 three-phase VT channels are connected to the bus side three-phase VTs with a
138 / 0.115 kV ratio.
•
The type 8V CT/VT module M1 to M3 and M5 to M7 three-phase VT channels are connected to two tap VTs with a
1.25 / 0.25 kV ratio. The nominal voltage is calculated below for normal bank conditions and a nominal system voltage
of 138 kV (see impedance calculations the following sub-section).
The nominal bus phase VT voltage is:
(EQ 10.1)
The nominal tap VT voltage is:
(EQ 10.2)
Therefore, the tap VT secondary voltage is set as:
(EQ 10.3)
Where the VT ratio
N
tap(VT)
is calculated as:
(EQ 10.4)
The following settings are applied in the EnerVista UR Setup software.
10.4.3 SOURCE ASSIGNMENT
The following sources must be assigned for the protection functions indicated.
•
Source 1 (bus) is assigned with CT and VT banks connected to the bus, providing a signal source for overcurrent,
phase current unbalance, overvoltage, and undervoltage functions.
V
tap bus
(
)
13800
3
----------------
79674.34 V
=
=
V
tap nominal
(
)
138000
Z
C
b
×
3
Z
C
t
×
---------------------------------
13800
4.08
×
3
1894.42
×
-----------------------------------
171.41 V
=
=
=
V
tap secondary
(
)
V
tap nominal
(
)
N
tap VT
(
)
---------------------------------
171.41 V
5
------------------------
34.28 V
=
=
=
N
tap VT
(
)
125 kV
0.25 kV
--------------------
5
=
=
Summary of Contents for UR Series C70
Page 2: ......
Page 10: ...x C70 Capacitor Bank Protection and Control System GE Multilin TABLE OF CONTENTS ...
Page 344: ...5 220 C70 Capacitor Bank Protection and Control System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 586: ...D 10 C70 Capacitor Bank Protection and Control System GE Multilin D 1 OVERVIEW APPENDIXD D ...
