1. Saxion University of Applied Sciences
POWER QUALITY
Deel A
Jentje Bootsma
Power Quality
Dips and Interruptions
2. Power Quality
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Dips and Interruptions
Introduction
Dips/Interruptions
UPS-DC/UPS-AC
Harmonics
Power Quality
Energie efficiëntie
Kosten
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Dips and Interruptions
Voltage dips are defined as sudden
reduction in voltage to lower voltages
for a short period of time, followed by
recovery to the original voltage.
Definition of Voltage Dips
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Dips and Interruptions
Short interruptions are defined as a
disappearance of AC voltage for a short
period of time, typically not exceeding 1
minute, followed by recovery to the original
voltage. Short interruptions can be considered
as voltage dips to zero volts.
Definition of Short Interruptions
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Dips and Interruptions
Voltage variations are gradual changes
of the supply voltage to a higher or
lower value than the rated voltage. The
duration can be short or long.
Definition of Voltage variations
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Dips and Interruptions
• Stroke of lightning on
• High voltage
• Medium Voltage
• Low voltage
• Short circuit
• High voltage
• Medium Voltage
• Low voltage
• Cable braking
• Starting large motors, transformers
Voltage dips can’t be avoided and will
propagate through the grid
Causes of dips
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Dips and Interruptions
Normal operation
10 ms 1 min
1%
90%
100%
110%
Under voltageVoltage dip
Short interruptions
3 min
Long interruptions
Over voltage
Voltage variations, dips and
transients
Definitions: NEN-EN 50160
No requirements
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Dips and Interruptions
IEC 61000-4-11
Classification of test results
• Performance Criteria A
‘Performance within specification limits’
• Performance Criteria B
‘Temporary degradation which is self-recoverable’
• Performance Criteria C
‘Temporary degradation which requires operator
intervention’
• Performance Criteria D
‘Loss of function which is not recoverable’
