4.21
Date Code 20090730 Instruction Manual SEL-734 Meter
Metering
Transformer/Line Loss Compensation
View Harmonic Metering Information
Via Serial Port
Use the MET H commands to display harmonic metering for the values
shown below. Unless indicated otherwise, voltage, current, and power
magnitudes are shown in secondary units. For more information, see MET
Commands on page 10.18).
Via Front Panel
The metering function available via serial port command MET H is also
available via the front-panel pushbuttons. See Figure 11.3.
Transformer/Line Loss Compensation
Estimate power transmission losses given known system parameters with
transformer/line-loss compensation. Calculations to implement loss
compensation in the SEL-734 are not required. Inputs to the meter use given
nameplate transformer specifications and line resistance. The meter adds or
subtracts the loss compensation based on these inputs.
Power is delivered from the power supplier to the point of consumption over a
network of transmission lines and through transformers. In addition to
generating power for customer loads, the power supplier must supply power to
overcome transmission system losses. To increase billing precision, the
SEL-734 can compensate for these resistive and inductive power transmission
losses. Without loss compensation, power suppliers are unable to bill
customers for losses that occur before the metering point.
In a system, there are four possible scenarios for the billing point as compared
to the meter position. Figure 4.8 and Table 4.10 show the addition and
subtraction of line and transformer loss compensation. Use the billing position
(BPOS) and meter position (MPOS) settings to replicate actual system
conditions.
Figure 4.8 Meter and Billing Positions
Ta b l e 4 . 9 M E T H Co m m an d
Command Values D isplayed
MET Voltage and current harmonic magnitudes as a percent of the fundamental
frequency magnitude, THD, K-Factor, Distortion Power Ratio
MET H M Voltage and current magnitudes
MET H I Current magnitudes and angles (degrees)
MET H V Voltage magnitudes and angles (degrees)
MET H P Power (watts)
Transformer
Load Line
Supply Line
BP1 BP3BP2 BP4
Load
Power
Supplier
Courtesy of NationalSwitchgear.com
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