Advanced | SIPZ

POWER AND IMPEDANCE – [SIPZ]
Compute the power, impedance, addition or subtraction of two signals for a given harmonic.

CATEGORY
Advanced

DESCRIPTION
This function allows to compute the power, impedance, addition or subtraction of two signals for a given harmonic.

RESULT VARIABLES AND PARAMETERS

Module (m)	Module (or amplitude) resulting from the operation specified for the harmonic multiplied by the absolute value of the factor.
Phase (a)	Angle a (or phase) resulting from the operation specified for the harmonic. Value is between -180 and 180 degrees [°]. Since the module is multiplied by the absolute value of the factor, the phase is modified if the multiplying factor is negative. In this case, 180 degrees are added to the phase.
Phase 0-360 (a0)	Angle a0 (or phase) resulting from the operation specified for the harmonic. Value is between 0 and 360 degrees [°].
Real (r)	Real part r of the module and angle computed (m * cos(a)).
Imaginary (i)	Imaginary part i of the module and angle computed (m * cos(a)). (m * sin(a)).
Signal_1	First signal to analyze (voltage signal).
Factor_1	Multiplying factor to use for all samples of signal 1.
Signal_2	Second signal to analyze (current signal).
Factor_2	Multiplying factor to use for all samples of signal 2.
Freq	Fundamental frequency of the signals in Hertz [Hz], normally computed with the sifreq function.
Harmonic number	Number of harmonic to compute. 0: DC; 1: Fundamental; 2: 2nd harmonic; n: nth harmonic (max. 30).
Operation	Operation to execute on the modules (or amplitudes) and angles of the required harmonic for each input signal. The modules and angles are first computed on the two input signals and then the specified operation is applied to these modules and angles. The defined operators are : p : power; / : impedance; * : multiplication; + : addition; - : subtraction;
Begin_time	Time at which the analysis of a signal must start. This time is expressed in milliseconds [ms]. This value must be greater than 0 and lower than the duration of the test. The default value is 0.
End_time	Time at which the analysis of a signal must end. This time is expressed in milliseconds [ms]. The value of this time must be larger than the specified begin_time and smaller than the duration of the test. Use the “HUGE” value to specify the end of the test. The default value is HUGE. The begin_time and end_time specified for the calculation of the harmonics must be the same as those used in the sifreq sequences to compute the fundamental frequency.
Factor	Multiplying factor for the results generated by the function. The default value of the multiplying factor is 1.0 and has no effect on the results.

SYNTAX

[m, a, a0, r, i] = sipz(a, 1, b, 1, 60, 1, "p", 0, HUGE, 1)

CHARACTERISTICS
Data type support
Double Floating point

EXAMPLE
The first diagram shows how to compute the different powers (p): apparent, active and reactive.

This function computes the apparent, active and reactive powers. For accurate calculations, voltage signals must be specified on the Signals1 line and current signals on the Signals2 line of the form.

The signs produced are based on the se-

S	Apparent power (complex)
P	Active power
Q	Reactive power
S	P+jQ

Inductive Load

Capacitive Load

The following diagram shows how to compute the different impedances (/): complex, resistance and reactance.

S	Complex impedance
P	Resistance
Q	Reactance
S	P+jQ

The resistance is equal to the real part (r) of the complex impedance.

Finally, the next diagram shows the different formulas used with the operations allowed: power (p), impedance (/), addition (+), subtraction (-) and multiplication (*).

Let:

m1	module of signal 1
m2	module of signal 2
a1	angle of signal 1
a2	angle of signal 2

Addition:

Subtraction:

Multiplication:

Impedance

Power (p)