Application Guide - NP900 Series
34 (504
)
Tracked F CHB
5…75.0Hz
0.1Hz
-
Display of the channel B tracked
frequency, rough value.
Tracked F CHC
5…75.0Hz
0.1Hz
-
Display of the channel C tracked
frequency, rough value.
3.1.4
P
OWER AND ENERGY CALCULATION
NP900 series IEDs with both voltage –and current cards can calculate power and have
power based protection and monitoring functions depending on the IED type. When power
calculation is possible also the energy magnitudes are calculated.
Power is divided into three magnitudes, apparent power S, active power P and reactive
power Q. Energy measurement is calculating magnitude for active and reactive energy.
Energy can be flowing to forward (exported) or reverse (imported) direction.
L
INE TO NEUTRAL VOLTAGES AVAILABLE
Power is calculated from line to neutral voltages and phase currents. In case line to line
voltages are connected the line to neutral voltages can be calculated based on measured
zero sequence voltage. In line to neutral mode and in line to line voltage measurement
mode when U0 is connected and measured the following equations apply for power
calculation:
Below is presented formula for three phase apparent power (S) calculation:
S
L1
= U
L1
× I
L1
S
L2
= U
L2
× I
L2
S
L3
= U
L3
× I
L3
S = S
L1
+ S
L2
+ S
L3
Where,
UL1…UL3 = Line to neutral voltage
IL1…IL3 = Phase current
Below is presented formula for three phase active power (P) calculation:
P
L1
= U
L1
× I
L1
cos
φ
P
L2
= U
L2
× I
L2
cos
φ
P
L3
= U
L3
× I
L3
cos
φ
P = P
L1
+ P
L2
+ P
L3
Where,
UL1…UL3 = Line to neutral voltage
IL1…IL3 = Phase current
φ
= Angle difference between
voltage and current
Содержание NP900 Series
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Страница 49: ...Application Guide NP900 Series 49 504 A996A Figure 3 2 1 3 25 Definite time operating characteristics...
Страница 50: ...Application Guide NP900 Series 50 504 A996A Figure 3 2 1 3 26 IEC predefined characteristics NI VI LTI and EI...
Страница 52: ...Application Guide NP900 Series 52 504 A996A Figure 3 2 1 3 28 IEEE predefined characteristics EI MI and VI...
Страница 243: ...Application Guide NP900 Series 243 504 A996A Figure 3 3 2 1 122 NPS biased thermal trip curves with kNPS values 7 and 10...
Страница 491: ...Application Guide NP900 Series 491 504 A996A 3 7 5 6 SETTING EXAMPLE...
Страница 504: ...Application Guide NP900 Series 504 504 A996A A996A...