GE L90 Instruction Manual page 438

6.3 METERING
The metered values for current and power demand are displayed in this menu. The "SRC 1" text will be replaced by what-
ever name was programmed by the user for the associated source (see
).
SOURCES
6
The relay measures (absolute values only) the source demand on each phase and average three phase demand for real,
reactive, and apparent power. These parameters can be monitored to reduce supplier demand penalties or for statistical
metering purposes. Demand calculations are based on the measurement type selected in the
menu. For each quantity, the relay displays the demand over the most recent demand time interval, the maxi-
DEMAND
mum demand since the last maximum demand reset, and the time and date stamp of this maximum demand value. Maxi-
mum demand quantities can be reset to zero with the
i) FREQUENCY METERING
PATH: ACTUAL VALUES
FREQUENCY
SRC 1
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
is measured via software-implemented zero-crossing detection of an AC signal. The signal is either a
SOURCE FREQUENCY
Clarke transformation of three-phase voltages or currents, auxiliary voltage, or ground current as per source configuration
(see the
SYSTEM SETUP
final frequency measurement is passed through a validation filter that eliminates false readings due to signal distortions and
transients.
If the 87L function is enabled, then dedicated 87L frequency tracking is engaged. In this case, the relay uses the
TRACKING FREQUENCY
6-18
SRC 1 DMD IC MAX:
MESSAGE
0.000 A
SRC 1 DMD IC DATE:
MESSAGE
2001/07/31 16:30:07
SRC 1 DMD W:
MESSAGE
0.000 W
SRC 1 DMD W MAX:
MESSAGE
0.000 W
SRC 1 DMD W DATE:
MESSAGE
2001/07/31 16:30:07
SRC 1 DMD VAR:
MESSAGE
0.000 var
SRC 1 DMD VAR MAX:
MESSAGE
0.000 var
SRC 1 DMD VAR DATE:
MESSAGE
2001/07/31 16:30:07
SRC 1 DMD VA:
MESSAGE
0.000 VA
SRC 1 DMD VA MAX:
MESSAGE
0.000 VA
SRC 1 DMD VA DATE:
MESSAGE
2001/07/31 16:30:07
METERING SOURCE SRC 1
SRC 1 FREQUENCY:
0.00 Hz
settings). The signal used for frequency estimation is low-pass filtered. The
POWER SYSTEM
TRACKING FREQUENCY
L90 Line Current Differential System
SETTINGS
CLEAR RECORDS CLEAR DEMAND RECORDS
FREQUENCY
SETTINGS SYSTEM SETUP
value for all computations, overriding the
6 ACTUAL VALUES
SYSTEM SETUP SIGNAL
SETTINGS PRODUCT SETUP
command.
).
SIGNAL SOURCES
METERING
value.
SOURCE FREQUENCY
GE Multilin