BE1-951
Metering
5-1
SECTION 5 • METERING
INTRODUCTION
The BE1-951 measures the voltage and current inputs, displays those values in real time, records those
values every one-quarter second, and calculates other quantities from the measured inputs.
METERING FUNCTIONS
BE1-951 metering functions include voltage, current, frequency, power factor, apparent power, reactive
power, and true power. Metered values are viewed through any communication port using serial commands
or at the front panel HMI. Metering functions are summarized in the following paragraphs and in Table 5-2.
For assistance with navigating through the HMI metering screens, refer to Section 10,
Human-Machine
Interface. For information on Power, VA, and var calculations, refer to Section 3, Input and Output
Functions, Power Calculations. Energy measurement is covered in Section 6.
Autranging
The BE1-951 automatically scales metered values. Table 5-1 illustrates the ranges for each value metered.
Table 5-1. Autoranging Scales for Metered Values
Metered Value
Unit Display Ranges
Whole units
Kilo Units
Mega Units
Giga Units
Current
0 A to 9,999 A
10 kA to 9,999 kA
10 MA
N/A
Voltage
0 V to 999 V
1 kV to 999 kV
1MV
N/A
Apparent Power
N/A
0 kVA to
999,999 kVA
1,000 MVA to
999,999 MVA
1 GVA
Reactive Power
N/A
0 kvar to
999,999 kvar
1,000 Mvar to
999,999 Mvar
1 Gvar
True Power
N/A
0 kW to
999,999 kW
1,000 MW to
999,999 MW
1 GW
Frequency
10 to 75 Hz
N/A
N/A
N/A
Voltage
The BE1-951 meters A phase voltage, B phase voltage, C phase voltage, voltage across phases A and B,
phases B and C, and phases A and C. Negative sequence voltage and three-phase zero sequence
(residual) voltage is also metered. The VTP connection determines what it measures.
Current
Metered current includes A phase current, B phase current, C phase current, neutral three-phase zero
sequence current, and ground current. Other metered currents include negative sequence current and
derived neutral current. All current measurements are auto ranging. Current is displayed in amps up to
9999A and then switches to kilo at 10.0KA to 9999KA.
Frequency
Frequency is metered over a range of 10 to 75 hertz. If the measured frequency is outside this range, the
nominal system frequency will be displayed. Frequency is sensed from A phase to Neutral for four-wire
sensing systems or from A phase to B phase for three-wire sensing systems.
