Appendix 9 Definitions
A 15
A
Unbalance
Factor
Because of the fluctuation of
loads on each phase, such as
when used for motive power or
operation of machinery that load
the phases unevenly, some
phases may be more heavily
loaded, causing more voltage or
current waveform distortion on
some phases than on others as
a result of voltage drop or
reactive voltage.
Voltage unbalance, reverse-
pha
se voltage and harmon-
ics can cause accidents re-
sulting from occurrence such
as
unstable motor rotation,
tripping of 3E breakers and
transformer thermal over-
load.
Power
Quality
Parameter
Waveform Display
Phenomenon Related Malfunctions
Transient
Overvoltage
(Impulse)
Occurs typically as a result of
lightning, circuit breaker trip-
ping, fouled relay contacts or
load shutdown.
Many cases exhibit abrupt
voltage changes and high peak
voltage.
Near the source of the phe-
nomena, power devices may
sustain damage or opera-
tions reset abruptly because
of the especially high volt-
age.
To Next Page
Loading...
