CHAPTER 7. INTEGRAL OPERATION FUNCTION
32
Table 6.3: Harmonic Parameters
The distortion factor calculation formulas and methods of different measurement functions are as follows:
Measurement function
%
r
%
f
(6.1)
Harmonic distortion factor of voltage
(6.2)
Harmonic distortion factor of current
(6.3)
Harmonic distortion factor of active power
(6.4)
Total harmonic distortion rate of voltage
(6.5)
Total harmonic distortion rate of current
(6.6)
Total harmonic distortion rate of active power(6.7)
NOTE Total harmonics are calculated as follows:
,
max
P
(
total
) = P
P
(
k
)
. k indicates the harmonic order, and max indicates the upper limit of analysis orders. max is
k
=0
determined by the frequency of PLL source automatically, 50
orders at most.
6.2.2
PLL source
In the harmonic mode, 5335C adopts PLL to multiply the frequency of the input signal. The frequency
multiplication output signal is used as the A/D sampling clock in the instrument so as to achieve the purpose of
synchronous sampling. Therefore, the frequency of the signal of the PLL source can determine the A/D sampling
clock in the instrument. However, the quality of the signal of the PLL source may affect the stability and accuracy
of sampling data.
6.2.2.1
PLL source selection
The voltage or current of the input unit can be selected as the PLL source. Used for determining the fundamental
wave cycle as the reference for analysis of harmonic orders. The fundamental wave frequency of the PLL source is
10Hz to 1.2kHz.