ABB LVS Digital FC610 User Manual page 9

T ERM IN OLOGY
Abbreviation Term
PF
V
U
dip
U
swl
U
int
U
nb
Uh
THD
u
I
h
THD
i
TN
TT
IT
TN-S
1T N C928 25 0M0 201
Power factor Vector
Voltage dip
Voltage swell
Voltage interruption
Unbalanced voltage
Amplitude of har-
monic voltage
Total harmonic dis-
tortion related to
voltage
Amplitude of har-
monic current
Total harmonic dis-
tortion related to
current
Description
Under periodic conditions, ratio of the vector of
the active power to the apparent power
Temporary reduction of the voltage magnitude at
a point in the electrical system below a threshold
Temporary increase of the voltage magnitude at a
point in the electrical system above a threshold
Voltage Interruption including Upg int (phase to
ground) and Vp int (Phase to N)
Voltage unbalance is a condition in which the
three-phase voltages differ in amplitude or are
displaced from their normal 120° phase relation-
ship, or both.
The amplitude of harmonic voltage applied by
Fourier analysis
Total harmonic distortion voltage of all harmonic
frequencies over the voltage of fundamental fre-
quency
The amplitude of harmonic current applied by
Fourier analysis
Total harmonic distortion current of all harmonic
frequencies over the current of fundamental fre-
quency
One of the points in the generator or transformer
is connected with earth, usually the star point in a
three-phase system. The body of the electrical de-
vice is connected to earth via this earth connec-
tion at the transformer.
The protective earth connection for the consumer
is provided by a local earth electrode, and there is
another independently installed at the generator.
There is no 'earth wire' between the two.
The electrical distribution system has no connec-
tion to earth at all, or it has only a high impedance
connection.
PE and N are separate conductors that are con-
nected only near the power source.
G ENER A L
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