Siemens SIMEAS R-PMU, Manual, Page: 47 / 296

6
6.3 Calculating Derived Values
47
Digital Fault Recorder, SIMEAS R-PMU, Manual
E50417-H1076-C360-A5, Release 10.2012
6.3 Calculating Derived Values
The SIMEAS R-PMU does not measure all values directly, some of the values are calculated
using the measured values. The following equations illustrate these calculations.
6.3.1 Voltage, Current and Power
Voltage
The Transient Analog Recorder (TAR) records the real signal curves, triggering is done using
the rms value of the half-wave with all harmonics.
x = 192/2 for f = f
n
The Transient Phasor Recorder (TPR) and the Continuous Phasor Recorder (CPR) consider
only the rms value of the fundamental component:
V
FC
FC: Fundamental Component (basic oscillation)
Current
The same applies to the calculation of the current rms value:
x = 192/2 for f = f
n
I
FC
FC: Fundamental Component (basic oscillation)
Active power
The active power is calculated using the rms value of the fundamental component:
Reactive power
The reactive power is calculated using the rms value of the fundamental component:
V
rms
1
x
---
v
n
2
n 1 =
x
∑
=
I
rms
1
x
---
i
n
2
n 1 =
x
∑
=
P
V
FC
I
FC
ϕ
cos
⋅ ⋅
=
Q
V
FC
I
FC
ϕ
sin
⋅ ⋅
=