GE PQMII, Инструкция по эксплуатации

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CHAPTER 6: MONITORING
PQMII POWER QUALITY METER – INSTRUCTION MANUAL 6–7
• Van, Vbn, Vcn : Displays phase voltages corresponding to the A, B, and C voltage
inputs. This voltage will be measured correctly only if the
VT RATIO
,
VT NOMINAL
SECONDARY
, and
VOLTAGE WIRING
setpoints match the installed VTs. If the displayed
voltage does not match the actual voltage, check the setpoints and wiring. This
message appears only if the
VT WIRING
is configured for a wye input.
• Iavg/Vavg : Displays the average of the three phase currents/voltages. This value is
not visible if the
VT WIRING
setpoint is set to “Single Phase Direct”. L-N is displayed when
VT WIRING
is set to “4 Wire Wye / 3 VTs”, “4 Wire Wye Direct”, “4 Wire Wye / 2 VTs”, or “3
Wire Direct” and L-L is displayed when
VT WIRING
is set to “3 Wire Delta / 2 VTs”.
• Vab, Vbc, Vca : Displays line voltages corresponding to the A, B, and C voltage inputs.
The measured voltage is correct only if the
VT RATIO
,
VT NOMINAL SECONDARY
, and
VOLTAGE
WIRING
setpoints match the installed VTs. If the displayed voltage does not match the
actual voltage, check the setpoints and wiring.
• AVERAGE LINE VOLTAGE : Displays the average of the three line voltages. This value is
not visible if the
VT WIRING
setpoint is set to “Single Phase Direct”.
• VOLTAGE UNBALANCE : Displays the percentage voltage unbalance. Voltage
unbalance is calculated as shown below. If the
VOLTAGE WIRING
is configured for a wye
input, voltage unbalance is calculated using phase quantities. If the
VT WIRING
is
configured as a delta input, voltage unbalance is calculated using line voltages.
(EQ 0.2)
where: V
avg
= average phase voltage = ( V
an
+ V
bn
+ V
cn
) / 3 for “Wye” and “3
Wire Direct” connections;
= average line voltage = (
V
ab
+ V
bc
+ V
ca
) / 3 for “3 Wire Delta / 2 VTs”
connection
V
m
= voltage in a phase (or line) with maximum deviation from V
avg
.
Note
Even though it is possible to achieve unbalance greater than 100% with the above
formula, the PQMII will limit unbalance readings to 100%.
If the average voltage is below 10% of
VT RATIO × VT NOMINAL SECONDARY VOLTAGE
for “3
Wire Delta / 2 VTs”, “4 Wire Wye / 3 VTs”, and “4 Wire Wye / 2 VTs” connections, or
below 10% of
VT RATIO
×
NOMINAL DIRECT INPUT VOLTAGE
for “4 Wire Wye/Direct” and “3
Wire Direct” connections, the unbalance reading is forced to 0%. This is implemented
to avoid nuisance alarms when the system is lightly loaded. If the simulation voltages
are being used, the unbalance is never forced to 0%.
• Van, Vbn, Vcn MIN/MAX : Displays the minimum/maximum phase voltage magnitudes
and the time and date of their occurrence. This information is stored in non-volatile
memory and is retained during loss of control power. The
S1 PQMII SETUP
ÖØ
CLEAR DATA
ÖØ
CLEAR MIN/MAX VOLTAGE VALUES
setpoint clears these values.
• Vab, Vbc, Vca MIN/MAX : Displays the minimum/maximum line voltage magnitudes
and the time and date of their occurrence. This information is stored in non-volatile
memory and is retained during loss of control power. The
S1 PQMII SETUP
ÖØ
CLEAR DATA
ÖØ
CLEAR MIN/MAX VOLTAGE VALUES
setpoint clears these values.
• V U/B MIN/MAX : Displays minimum/maximum voltage unbalance and the time and
date of its measurement. This information is stored in non-volatile memory and is
retained during loss of control power. This value is cleared with the
S1 PQMII SETUP
ÖØ
CLEAR DATA
ÖØ
CLEAR MIN/MAX VOLTAGE VALUES
setpoint.
Voltage Unbalance
V
m
V
avg
–
V
avg
--------------------------- 100% ×
=