Download Harmonics Filter Design

Ahmad Hassan AlObaidly and Abdulaziz Abdulla Alshafai
Supervisor: Dr. Khaled Ellithy
Department of Electrical Engineering, College of Engineering
FALL 2008
Introduction
Objectives
In recent years, harmonics are considered as one of the most
essential problems in the industrial power distribution networks.
The problem of harmonics is increasing due to the use of the
variable speed drives (VSDs), the uninterruptible power supplies
(UPS), and the solid-state devices. Harmonics current distortion
may produce negative effects on the power quality of the power
networks. The negative effects include malfunctioning of
sensitive devices such as protective relays, motors overheating,
and transformer overheating. The current total harmonic
distortion (THD) can be reduced to the IEEE standards using
harmonics filters such as passive harmonic filters or active
harmonic filters.
To conduct a study on harmonics, harmonics sources, harmonics
representation, harmonics effects, and harmonics indices.
To study the recommended IEEE-519 standards for the current
and voltage harmonics distortion.
To conduct a study on the types of harmonics filters.
To conduct a study on passive harmonics filters design.
To perform the harmonics analysis and harmonics filter design
for a typical gas plant power network using EDSA power system
analysis software.
Harmonics Indices and IEEE 510 Standards
"Harmonics" term in an AC power system is defined as a sinusoidal component
of a periodic waveform that has a frequency equal to an integer multiples of the
fundamental frequency (50 Hz) of the power network.
The Total harmonic distortion (THD) is a measure of the effective value of the
harmonic components of a distorted waveform.
Power Distribution Network Model for Harmonics
Analysis of a Train in a Typical Gas Plant
IEEE 519 standard of voltage harmonics distortions
The THD of voltage is given by
%THDV 
Vh, RMS
V1
Bus Voltage at PCC
(KV)
Individual
harmonic voltage
distortion (%)
Total Voltage Distortion,
THD (%)
V < 69
3.0
5.0
69 < V < 161
1.5
2.5
V > 161
1.0
1.5
V22  V32  ......  VN2
100 
100
V1
IEEE 519 standard of current harmonics distortions
Maximum harmonic current distortion in percentage of the fundamental V ≤ 69 kV
I1
I 22  I 32  ......  I N2
100
I1
100 
11≤h<17
17≤h≤23
23≤h≤35
<20
4.0
2.0
1.5
0.6
0.3
5.0
20-50
7.0
3.5
2.5
1.0
0.5
8.0
50-100
10.0
4.5
4.0
1.5
0.7
12.0
100-1000
12.0
5.5
5.0
2.0
1.0
15.0
>1000
15.0
7.0
6.0
2.5
1.4
20.0
%
Computer Simulation Results without Harmonics
Filters
Single-line diagram of power distribution
network Including harmonics sources
Harmonics Filter Design
A passive harmonic filter is designed to eliminate the 11th harmonic order for HR5343
EDSA Harmonic Analysis
544.3
QC  VLL C  2000  10 3  (33000 2 ) * (2 * 50) * C
2
HR-5343
%THDi= 42.55%
UPS-A
%THDi= 41.38%
EDSA Harmonic Analysis
EDSA Harmonic Analysis
150.0
100.0
Magnitude %
Magnitude %
100.0
150.0
50.0
0.0
-50.0
50.0
0.0
-50.0
-100.0
-100.0
-150.0
-150.0
0
80
160
240
320
400
480
560
640
0
720
80
160
240
320
400
480
560
640
720
EDSA Harmonic Analysis
EDSA Harmonic Analysis
100.0
83.3
83.3
Magnitude %
100.0
66.7
50.0
33.3
33.3
0.0
0.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
0.0
50.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
Harmonic
Harmonic
The current total harmonic distortions (42.55% and 41.38%) exceed the IEEE-519
standards
Computer Simulation Results with the Designed
Harmonics Filters
HR-5343
%THDi=7.37%
UPS-A
%THDi=2.98%
EDSA Harmonic Analysis
150.0
100.0
100.0
50.0
Magnitude %
Magnitude %
EDSA Harmonic Analysis
150.0
0.0
-50.0
-100.0
0.0
-50.0
-100.0
-150.0
-150.0
0
80
160
240
320
400
480
560
640
720
0
80
160
240
320
400
480
Angle in Degrees
Angle in Degrees
EDSA Harmonic Analysis
EDSA Harmonic Analysis
100.0
100.0
83.3
83.3
Magnitude %
Magnitude %
50.0
66.7
50.0
33.3
16.7
560
640
720
45.0
50.0
66.7
50.0
33.3
16.7
0.0
0.0
0.0
5.0
10.0
15.0
20.0
25.0
Harmonic
30.0
35.0
40.0
45.0
50.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
Harmonic
The current total harmonic distortions (7.37% and 2.98%) are within the IEEE-519 standards.
272.1
181.4
90.7
111
222
333
444
556
667
778
889
1000
778
889
1000
Frequency (Hz)
 C  1.8482  10 3 F
50.0
362.8
0
2
66.7
453.6
0.0
QC  VLL C  100  10 3  (415 2 ) * (2 * 50) * C
16.7
16.7
1
XC 
 548.811
2 * 50 * C
X
X L  2C  4.53562
h
Passive harmonic filter to eliminate the 5th
harmonic order for UPS-A
Angle in Degrees
Angle in Degrees
Magnitude %
 C  5.8  10 6 F
Impedance Response (Ohms)
%THDI 
I h, RMS
h<11
1
XC 
 1.72225
2 * 50 * C
X
X L  2C  0.06889
h5
EDSA Harmonic Analysis
1.653
Impedance Response (Ohms)
The THD of current is given by
TDD%
35≤h
ISC / IL
1.378
1.102
0.827
0.551
0.276
0.000
0
111
222
333
444
556
667
Frequency (Hz)
The voltage and kVAR of the harmonics filter capacitor have been checked with
limits recommended by ANSI/IEEE 18-1980 standards.
Conclusions
 Harmonics sources, harmonics effects and harmonics representation
have been presented.
 An industrial power distribution network of a gas plant was chosen for
the study.
 Measurements of the current and voltage harmonics distortions at the
Gas Plant were conducted using AEMC power quality analyzer.
 The plant power distribution network for harmonics analysis was
developed using EDSA power systems analysis software.
 The harmonics filters were designed to eliminate the dominant
harmonics orders to reduce the THD of the current and voltage to the
allowable limits recommended by the IEEE 519 standards.
 The maximum limits of voltage and kVAR of the harmonics filter
capacitor have been checked with the ANSI/IEEE 18 standards.