KMB NOVAR 2600, Operating Manual

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NOVAR 2600 Operating Manual
4.4.6.1 Values Used for Power Factor Control Evaluation and
Aggregation
Powers Pfh and Qfh of individual phases are basic quantities used for power factor control. Values of
the quantities are evaluated each measurement cycle. Then they are internally
averaged with
floating 5 seconds long window for usage in power factor control with contactor-type outputs. Such
power values are not displayed, but essential quantities for power factor control – PF control
deviations ΔQfh – are evaluated from them. In the same way, compensation reserves RC and RL are
evaluated.
Therefore, the control deviations and the power factor control intentionally do not react on short power
factor deflections that cannot by compensated with contactor-type outputs.
4.4.6.2 ΔQfh – PF Control Deviation
This is crucial quantity for the PF control process. Its value indicates surplus reactive power ( of
fundamental harmonic component ) in the network that must be compensated to reach preset target
power factor. If the value is positive ( inductive character ) the controller connects compensation
capacitors of appropriate power to the network; if negative ( capacitive character ), the controller tries
to add compensation chokes.
Target fundamental harmonic component reactive power of phase L1:
Qfh
T 1
=
Pfh
1
∗
tgφ
T
where :
Pfh1 … phase L1 fundamental harmonic active power
φ
T
… preset target angle between fundamental voltage and current phasors
When target power factor is specified in the cosφ format it can be declared :
Target angle (between fundamental U & I phasors) :
φ
T
= arcsin ( cosφ
T
)
Then, target fundamental harmonic component reactive power (of phase L1) is :
Qfh
T 1
=
Pfh
1
∗
tg
(
arcsin
(
cosφ
T
))
Finally, the control deviation of phase L1 :
ΔQfh
1
= Qfh
1
− Qfh
T 1
where :
Qfh1 … phase L1 fundamental harmonic reactive power
Total three-phase control deviation :
∑
ΔQfh
=
ΔQfh
1
+
ΔQfh
2
+
ΔQfh
3
4.4.6.3 Cosφ / Tanφ / φ – Power Factor
The fundamental harmonic component power factor value processed in the PFC-block can be
presented not only in
the cosφ
format but as
the tanφ
or simply as
the φ
too.
The power factor character in the PFC-block is marked with either -icon (inductive character) or -
icon (capacitive character ).
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