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PQM POWER QUALITY METER – INSTRUCTION MANUAL
S4 ALARMS/CONTROL
CHAPTER 4: PROGRAMMING
advantageous to compensate for low (lagging) power factor values by connecting a
capacitor bank to the circuit when required. The PQM provides power factor monitoring
and allows two stages of capacitance switching for power factor compensation.
FIGURE 4–29: Capacitor Bank Switching
The PQM calculates the average power factor in the three phases, according to the
following equation:
Two independent “elements” are available for monitoring power factor, POWER FACTOR 1
and POWER FACTOR 2, each having a pickup and a dropout level. For each element, when
the measured power factor is equal to or becomes more lagging than the pickup level (i.e.
numerically less than), the PQM will operate a user-selected output relay. This output can
be used to control a switching device which connects capacitance to the circuit, or to
signal an alarm to the system operator. After entering this state, when the power factor
becomes less lagging than the power factor dropout level, the PQM will reset the output
relay to the non-operated state.
Both power factor 1 and 2 features are inhibited from operating unless all three voltages
are above 20% of nominal and one or more currents is above 0. Power factor 1 and 2 delay
timers will be allowed to time only when the 20% threshold is exceeded on all phases (and,
of course, only while the power factor remains outside of the programmed pickup and
dropout levels). In the same way, when a power factor condition starts the power factor 1
or 2 delay timer, if all three phase voltages fall below the 20% threshold before the timer
has timed-out, the element will reset without operating. A loss of voltage during any state
will return both power factor 1 and 2 to the reset state.
Average Power Factor
Total 3-phase Real Power
Total 3-phase Apparent Power
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Содержание Multilin PQM
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