SETTINGS EXAMPLE
•
Source 2 (tap 1) and source 3 (tap 2) are assigned with the VT banks and split window CT bank connected to the tap
point of two strings of the bank, providing a signal source for the voltage differential and phase unbalance functions
The CT and VT connections shown in the earlier figure are assigned the following values in EnerVista UR Setup.
8.4.4 Bank unbalance calculations
The following values are used in unbalance calculations.
The impedance of one capacitor can:
The impedance of one capacitor element, with n = 6 capacitor elements per can:
The impedance of the top healthy capacitor string:
The impedance of the bottom capacitor can:
The total impedance of the healthy capacitor string:
The maximum rated line-to-neutral system voltage:
8
V
The maximum rated phase current of the healthy bank:
The maximum rated voltage across the healthy top section:
8-14
2
V
c
C
Z
=
------ -
C
Q
C
e
Z
=
C
s
c
Z
=
Z
×
C
C
V
b
Z
=
-------- -
C
Q
t
s
b
Z
=
Z
+
Z
C
C
C
V
×
N
C
b
-------------- -
=
V
×
N
+
×
Z
=
max
C
C
s
Z
C
V
max
I
=
----------- -
max
t
Z
C
s
V
×
Z
max
C
V
=
----------------------
=
top
t
Z
C
2
(
11.62 V
)
=
----------------------------------- -
=
270.05Ω
3
–
500
×
10
vars
c
Z
270.05Ω
C
---- -
=
------------------- -
=
45.01Ω
n
6
N
=
270.05Ω 7
×
=
1890.34Ω
2
2
(
0.825 V
)
CN
=
----------------------- -
=
4.08 Ω
0.167 var
CN
=
1890.34Ω 4.08Ω
+
=
1894.42Ω
11620 V 7
×
--------------------------- -
11620 V 7
×
+
×
4.08 Ω
1890.34Ω
81515.37 V
=
----------------------------- -
=
86.06 A
1894.92Ω 2 ⁄
2 ⁄
81515.37 V 1890.34Ω
×
------------------------------------------------------ -
=
81340.40 V
1894.92Ω
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
CHAPTER 8: APPLICATION OF SETTINGS
=
81515.37 V
Eq. 8-5
Eq. 8-6
Eq. 8-7
Eq. 8-8
Eq. 8-9
Eq. 8-10
Eq. 8-11
Eq. 8-12