ABB LVS Digital FC610 - 3.3 Power Quality; 3.3.1 Harmonics Measurement

POWER QUALIT Y PR ODUCT FU NCTION S
1TNC9 2825 0M0201 21
3.3 Power quality
3.3.1 Harmonics measurement
Harmonics refers to the amount of electricity contained in the current that is an integral mul-
tiple of the fundamental (i.e., 50 Hz or 60 Hz). FC610 measures total harmonic distortions as
well as individual harmonics up to 31st harmonic.
Total Harmonics
Individual Harmonic
THD of current L1
Harmonic I1 3rd to 31st
THD of current L2
Harmonic I2 3rd to 31st
THD of current L3
Harmonic I3 3rd to 31st
THD of voltage L1
Harmonic U1 3rd to 31st
THD of voltage L2
Harmonic U2 3rd to 31st
THD of voltage L3
Harmonic U3 3rd to 31st
THD of voltage U12
Harmonic U12 3rd to 31st
THD of voltage U23
Harmonic U23 3rd to 31st
THD of voltage U31
Harmonic U31 3rd to 31st
3.3.2 Current unbalance supervision
FC610 monitors unbalanced current and current unbalanced condition.
Unbalanced current is presented as a percentage value following below calculation and displayed di-
rectly through HMI.







 






 






 





where





 

 


The current unbalance threshold and hysteresis is a percentage value. A current unbalance
event is detected when current unbalance value I
nba
is above the threshold. The event ends
when the I
nba
is equal to or below the value of the threshold minus the hysteresis.