hager hw+ - 6.5 Measuring power

86 6LE008146B
Measurement functions
6.5 Measuring power
The sentinel Energy trip unit calculates the following electrical powers in real-time (every
second):
- Active power per phase
- Reactive power per phase
- Apparent power per phase
- Total active power
- Total reactive power
- Total apparent power.
The exhaustive list of variables calculated, associated with their mathematical definition and
their availability according to 3-pole or 4-pole version, is given in the following table:
Details about the calculations
The calculations of these powers take into account the harmonics up to rank 40.
Electrical parameter Symbol Definition 3-pole
version
4-pole
version
Active power per phase P1, P2, P3
-
■
Apparent power per
phase
S1, S2, S3
A
-
■
Reactive power per
phase
Q1, Q2, Q3
-
■
Total active power Ptot On a 4-pole product P
tot
= P
1
+ P
2
+ P
3
.
The 2 wattmeter method is used on a
3-pole product
■ ■
Total reactive power Qtot
Vector or arithmetic addition depend-
ing on configuration, see § 6.13
■ ■
Total apparent power Stot
Vector or arithmetic addition depend-
ing on configuration, see § 6.13
■ ■
Symbol Definition
N Total number of samples per network period
T Period measured, in seconds
k sample number of phase p current
k sample number of voltage between phase p and neutral
Phase dierence between the current and the voltage for phase p
Rank i harmonic component