This document discusses power quality issues related to voltage dips and interruptions. It defines voltage dips as sudden reductions in voltage for short periods of time, followed by recovery to the original voltage. Short interruptions are defined as the disappearance of AC voltage for less than a minute, followed by recovery. Causes of dips include lightning strikes, short circuits, and starting large motors. The document also discusses dip profiles, immunity testing standards IEC 61000-4-11, and classifications of test results.

1. Saxion University of Applied Sciences
POWER QUALITY
Deel A
Jentje Bootsma
Power Quality
Dips and Interruptions

2. Power Quality
2
Dips and Interruptions
Introduction
Dips/Interruptions
UPS-DC/UPS-AC
Harmonics
Power Quality
Energie efficiëntie
Kosten

3. Power Quality
3
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

4. Power Quality
4
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

5. Power Quality
5
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

6. Power Quality
6
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

7. Power Quality
7
Dips and Interruptions
Influences decreases
with distance
Propagation of dips

8. Power Quality
8
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
T
r
a
n
s
i
e
n
t
s
t

9. Power Quality
9
Dips and Interruptions
Dip profile
120 ms
Dips

10. Power Quality
12
Dips and Interruptions

11. Power Quality
13
Dips and Interruptions

12. Power Quality
14
Dips and Interruptions
IEC 61000-4-11
Immunity testing

13. Power Quality
15
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’