Hioki PQ3198 - Page 267

A3
Appendix
Voltage swell
(SURGE)
Swells occur when the
voltage rises m
omen-
tarily, for example when
a power line turns on or
off due to lightning or a
heavy load, when a
high-capacity capacitor
bank is switched, when
a one-line ground
occurs, or when a high-
capacity load is cut off.
This phenomenon also
includes voltage surges
due to grid-tied dis-
persed power supplies
(solar power, etc.).
A surge in voltage may
cause the device's
power to be damaged
or the device to reset.
Events are detected
using swells.
Flicker
Flicker consists of volt-
age fluctuations result-
ing from causes such
as bla
st furnace, arc
welding, and thyristor
control loads. Manifes-
tations include light
bulb flicker.
Because this phenom-
enon reoccurs regu-
larly, it may cause the
light to flicker or the
device to malfunction.
Large flicker values
indicate that most peo-
ple would find the flick-
ering of lighting
unpleasant.
Events are measured
using ΔV10 flicker and
IEC flicker Pst and Plt.
Interruption
(momentary
pow
er outage)
Interruptions consist of
momentary, short-
term, or extended
power supply outages
as a result of factors
such as circuit break-
ers being tripped due
primarily to power
company issues (inter-
ruption of power due
to lightning strikes,
etc.) or power supply
short-circuits.
Recently, due to the
spread of UPS (unin-
terruptible power
sources), most of
these problems can be
fixed using a com-
puter, but this may
cause the device to
stop operating due to
an interruption or to
reset.
Events are detected
using interruptions.
Harmonic
Harmonics are caused
by distortion
s of the
voltage and current
waveforms when a
device’s power supply
uses semiconductor
control devices.
Large harmonic com-
ponents can lead to
major malfunctions,
including overheating
of motors and trans-
formers and burnout of
reactors connected to
phase advance capac-
itors.
Events are detected
using harmonic volt-
age, harmonic cur-
rent, and harmonic
power. They can also
be detected as voltage
waveform distortions
using voltage wave-
form comparison func-
tionality.
Inter-harmonics
Inter-harmonics are
cau
sed when the volt-
age or current wave-
form is distorted due to
static frequency con-
version equipment,
cycloconverters,
Scherbius machines,
induction motors,
welders, or arc fur-
naces. The term refers
to frequency compo-
nents that are not a
whole multiple of the
fundamental wave.
Displacement of the
voltage waveform
zero-cross may dam-
age equipment, cause
it to malfunction, or
degrade its perfor-
mance.
Inter-harmonics are
measured using inter-
harmonic voltage and
inter-harmonic cur-
rent. Events are not
supported, but it may
be possible to detect
events as voltage
waveform distortions
using voltage wave-
form comparison func-
tionality.
Principal
parameters
indicating
power quality
Waveform Phenomenon Primary issues
PQ3198 events and
measurements
HIOKI PQ3198A961-02