LS Industrial Systems Metasol Series, Технический каталог

Страница: 50 / 156

49
D
: Power Production
: Power Consumption
3. Apparent Power Calculation
1) Apparent power defines as current RMS value x voltage RMS value.
2) In case of no harmonic factors, the power equation formulates.
3) However, if harmonic is included, the equation of power does not formulate.
4) Thus, to avoid confusion of P and S type users, evaluate active and reactive power first and then evaluate
apparent power by using, not by using current RMS value x voltage RMS value.
4. Power Factor Calculation
1) Evaluate the size of power factor with the Pf = active power/apparent power equation.
5. Indication of Power and Power Factor According to Phase
6. Electric Energy - Bidirectional Metering
Integrate separately by classifying power into receiving and transmission.
1. Active electric energy, reactive electric energy, reverse active electric energy, reverse reactive electric energy
2. Refer to above figure for classification of corresponding factors.
3. Concerning the size of power factor, the symbols have the meaning as the above figure.
I
V
I
V
I
V
I
V
1 quadrant
Power > 0
Reactive Power < 0
PF > 0
90
0 180
270
4 quadran
Power > 0
Reactive Power > 0
PF > 0 3 quadrant
Power < 0
Reactive Power > 0
PF < 0
2 quadrant
Power < 0
Reactive Power < 0
PF < 0
S =
√
P + Q
2 2
S =
√
P + Q
2 2
Digital Trip Relay
5. Measurement Function
Lag Lead
Lag Lead