Ieee std 1159-1995, ieee recommended Practice for Monitoring Electric Power Quality

5.3 Equipment tolerances and effects of disturbances on equipment
The tolerance of various equipment needs to be considered in power quality monitoring. A speciÞc type of
equipment, such as an ASD, may be sensitive to an overvoltage or undervoltage condition, for example,
while there may also be a signiÞcant variation to the same phenomena between ASDs built by other manu-
facturers. Power quality monitoring should attempt to characterize individual process equipment by match-
ing monitoring results with reported equipment problems. This characterization of individual loads will
show which equipment needs protection, and the level of protection required.
5.4 Equipment types 
Although there may be a wide variety in the response of speciÞc equipment types manufactured by different
companies, there may be some similarity in the response of certain types of equipment to speciÞc distur-
bance parameters. In any case, it is useful to consider certain speciÞc equipment types or groupings in terms
of their immunity to power quality disturbances.

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IEEE
Std 1159-1995
IEEE RECOMMENDED PRACTICE FOR
26
Figure 13ÑSample customer disturbance recording form
5.5 Effect on equipment by phenomena type
Clause 4 deÞnes seven major categories of electromagnetic phenomena. The following subclauses describe
the observed effects of these phenomena on the operation of various types of equipment.
5.5.1 Transients
Transient voltages caused by lightning or switching operations can result in degradation or immediate
dielectric failure in all classes of equipment. High magnitude and fast rise time contribute to insulation
breakdown in electrical equipment like rotating machinery, transformers, capacitors, cables, CTs, PTs, and
switchgear. Repeated lower magnitude application of transients to these equipment type cause slow degrada-
tion and eventual insulation failure, decreasing equipment mean time between failure (MTBF). In electronic
equipment, power supply component failures can result from a single transient of relatively modest magni-
tude. Transients can also cause nuisance tripping of adjustable speed drives due to the dc link overvoltage
protection circuitry.