Pq 3Unf - ABB REX 521 Technical Reference Manual, Standard Configurations

1MRS 751802-MUM
7.5.2.
Protection Relay
Technical Reference Manual, Standard Configurations
Current waveform distortion measurement, PQ 3Inf
Harmonic limit supervision
Limit for THD
Limits for each harmonic
Recorded data
Current waveform distortion measurement, PQ 3Inf
Operation criteria
Fundamental frequency
Frequency deviation
Amplitude of the fundamental wave
Measurement accuracy
Measured harmonic Im = 1st,...,
10th
Measured harmonic Im = 11th,...,
13th

PQ 3Unf

The function block PQ 3Unf is used for measuring the harmonics and monitoring
the power quality in distribution networks. Power quality measurements carried out
by the function block PQ 3Unf follow the European Standard EN 50160. Data
collection and analysis is done according to EN 50160. Measuring principles for
individual harmonics and THD are adapted from the International standard IEC
61000-4-7. The American standard IEEE Std 1159 is also partly supported.
The function block measures quasi-stationary (slowly varying) harmonics up to
13th.
Distortion measurement does not include rapidly changing harmonics,
interharmonics or other spurious components.
PQ 3Unf
TRIGG HAR_HIGH
RESET CUM_HIGH
)LJ  )XQFWLRQ EORFN V\PERO RI 34 8QI
Voltage waveform distortion measurement, PQ 3Unf
The voltage waveform distortion measurement PQ 3Unf is used for measurement and statistical
analysis of voltage waveform distortion. The standards concerning current distortion measurement are
applied to current distortion measurement in PQ 3 Inf. Data collection and analysis is done according
to EN 50160. Measuring principles for individual harmonics and THD are adapted from the
International standard IEC 61000-4-7. The American standard IEEE Std 1159 is also partly supported.
Analysis can be done for one selected phase voltage or phase-to-phase voltage or most distorted
voltage can be tracked.
Measuring modes
Measurement activation
0.0... 60.0%
0.0... 40.0% In
If any limit should be exceeded, the whole harmonic set will be
recorded during the maximum THD (3 sec values)
0.9... 1.1 Fn
≤ 0.5 Hz (difference between max. and min. values within one
second)
≥ 1% In
In accordance with IEC 61000-4-7
± 1.0% In, if Im < 10% In; ± 10% Im, if Im ≥ 10% In
Not in use, L1, L2, L3, Worst phase, L1-L2, L2-L3, L3-L1
Worst main
Triggering by: setting parameter, binary input, date & time
Setting
REX 521
99