GE C70, Instruction Manual

Page: 411 / 708

GE Multilin C70 Capacitor Bank Protection and Control System 6-17
6 ACTUAL VALUES 6.3 METERING
6
The metered values for real, reactive, and apparent power, as well as power factor, are displayed in this menu. The "SRC
1" text is replaced by whatever name was programmed by the user for the associated source (see
SETTINGS

SYSTEM
SETUP

SIGNAL SOURCES
).
When VTs are configured in wye, the C70 calculates power in each phase and three-phase power is measured as
S = V
A
x Î
A
+ V
B
x Î
B
+ V
C
x Î
C
(EQ 6.1)
When VTs are configured in delta, the C70 does not calculate power in each phase and three-phase power is measured as
S = V
AB
x Î
A
+ V
CB
x Î
C
(EQ 6.2)
where
S is the apparent power
V
A
, V
B
, V
C
, I
A
, I
B
, I
C
are phase voltage and phase current phasors
V
AB
and V
CB
are phase-to-phase voltage phasors
Î is the conjugate of I
g) FREQUENCY METERING
PATH: ACTUAL VALUES

METERING

SOURCE SRC 1

FREQUENCY
The metered frequency values are displayed in this menu. The "SRC 1" text will be replaced by whatever name was pro-
grammed by the user for the associated source (see
SETTINGS

SYSTEM SETUP

SIGNAL SOURCES
).
SOURCE FREQUENCY
is measured via software-implemented zero-crossing detection of an AC signal. The signal is either a
Clarke transformation of three-phase voltages or currents, auxiliary voltage, or ground current as per source configuration
(see the
SYSTEM SETUP

POWER SYSTEM
settings). The signal used for frequency estimation is low-pass filtered. The
final frequency measurement is passed through a validation filter that eliminates false readings due to signal distortions and
transients.
MESSAGE
SRC 1 APPARENT PWR
φ
c: 0.000 VA
MESSAGE
SRC 1 POWER FACTOR
3
φ
: 1.000
MESSAGE
SRC 1 POWER FACTOR
φ
a: 1.000
MESSAGE
SRC 1 POWER FACTOR
φ
b: 1.000
MESSAGE
SRC 1 POWER FACTOR
φ
c: 1.000

FREQUENCY

SRC 1
SRC 1 FREQUENCY:
0.00 Hz