Below is presented formula for three phase reactive power (Q) calculation:
Q
L1
= U
L1
× I
L1
sin
φ
Q
L2
= U
L2
× I
L2
sin
φ
Q
L3
= U
L3
× I
L3
sin
φ
Q = Q
L1
+ Q
L2
+ Q
L3
Where,
UL1…UL3 = Line to neutral voltage
IL1…IL3 = Phase current
φ
= Angle difference between
voltage and current
Active power direction can be to forward or reverse direction. Active power direction can
be indicated simply by using Cos (
φ
). Cosine phi is calculated according the following
formula:
3PH Cos(phi) = P S
�
L1 Cos(phi) = P
L1
S
L1
�
L2 Cos(phi) = P
L2
S
L2
�
L3 Cos(phi) = P
L3
S
L3
�
Direction of reactive power is divided in to four quadrants. Reactive power may be
inductive or capacitive on both forward and reverse direction. Reactive power quadrant
can be indicated simply by using Tan (
φ
) together with Cos (
φ
). Tangent phi is calculated
according the following formula:
3PH Tan(phi) = Q P
�
L1 Tan(phi) = Q
L1
P
L1
�
L2 Tan(phi) = Q
L2
P
L2
�
L3 Tan(phi) = Q
L3
P
L3
�
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...