Emerging trends in Engineering & Management for Sustainable Development 2016
International conference, Feb 2016
APSO Based Optimal Allocation And Sizing Of
An APLC System
Jayanti Choudhary
Electrical Engineering Department, N.I.T. Patna, Bihar, India
jayantichoudhary @gmail.com, jayanti@nitp.ac.in
Dr. D.K.Singh
Electronics and Communication Engineering Department, N.I.T. Patna, Bihar, India
dksingh@nitp.ac.in
Dr. S.N.Verma
Department of Electrical Engineering, N.I.T. Patna, Bihar, India
snverma@nitp.ac.in:
Abstract— With day-by-day increasing significance of
Power Electronics, the issue of harmonics being introduced
in electrical systems needs to be addressed on a priority
The use of these nonlinear loads containing non linear
power electronics elements pollutes the system by
injecting harmonic current into the system.
A. Impact of Harmonics in Distribution System
basis. Active Filters are very apt solution for reducing
harmonics.In this study, the optimal placement and sizing
problem of multiple active power line conditioners
("APLCs") in a distribution system is considered. The
heuristic
optimization
technique
particle
swarm
optimization is implemented for allocating and sizing. Here
The harmonics produced by nonlinear power
electronic devices may cause premature motor burnout,
computer network failure, humming in telephone line,
transformer overheating etc. in homes and industries
where it is installed. This impacts may be seemed like
small problem but can bring an industry into stand still.
B. Solution To Harmonics Problem
five individual harmonic correction parameters as Total
Harmonic
Distortion
("THD"),
Motor
Load
Loss
("MLL"), Harmonic Transmission line Loss ("HTLL"),
There are two methods to improve the power quality
I.
Telephone Influence Factor ("TIF") and APLC current
are considered. The objective function is a function of
these five individual parameters. Here the optimal
allocation and sizing problem is addressed in a 18 Bus
IEEE test system for six harmonics (5th, 7th, 11th, 13th,
17th, and 19th). First Particle Swarm Optimization (PSO)
is used to find an optimal solution for this problem in a
standard 18-bus system and then Adaptive PSO (APSO) is
used which gives still better result.
Index Terms— APLC, APSO, PSO, THD, Power quality.
I. INTRODUCTION
In modern distribution systems nonlinear load, i.e.
Converters, inverters, adjustable motor speed drives
computers, computer peripherals etc are more often used
to reduce the human work load and also to offer more
luxury.
II.
Load conditioning: Here the loads are made less
sensitive to power quality. This causes
significant voltage distortion.
Placing power line conditioner:
Here power electronic line conditioners are placed in
the system. There are two types of power line
conditioner passive or active.
Passive line conditioners are nothing but passive
filters. They are easy to implement but there use is
limited to fewer harmonic problem and also there may
occur resonance.
However, active line conditioner i.e. active filters are
most widely used in modern power system to improve
the power quality. These active power line conditioners
(APLCs) improve the power quality by reducing the
harmonics by injecting harmonics of 1800 phase shift.
Though an APLC have large number of advantages,
its operating cost and cost due to size stops an engineer
from installing this instrument in all the busses in the
distribution system. However, If multiple nonlinear loads
are present in the system, then the use of one APLC may
not give good compensation of harmonics.
In this study heuristic algorithm PSO is used for
optimal allocation and sizing of APLCs in a 18 bus IEEE
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Emerging trends in Engineering & Management for Sustainable Development 2016
International conference, Feb 2016
 Harmonic transmission line loss:
standard test system and then Adaptive PSO (APSO) is
used.
II. PROBLEM FORMULATION
In this paper multiple APLC allocation sizing problem
is addressed. From literature survey it is seen that the
APLC allocation and sizing is initially studied
considering single objective functions(OF) at a time in
[6]-[10] using different optimization techniques, then the
problem was studied for lumped objective function in
[1]. In [6]-[10] optimal allocation and sizing problem of
APLC is analyzed using one of the following objective
functions Total harmonic distortion(THD),

Motor load loss(MLL),

Harmonic transmission line loss(HTLL),

Telephone influence factor(TIF),

APLC current.
(4)
 Average telephone influence factor:
(5)
Where
 Average APLC current:
In paper [1] the problem is analyzed by lumping
objective functions-THD, MLL, HTLL and APLC
current.
In this work this problem is analyzed by taking
weighted lumped objective function. The objective
function is a function of five harmonic parameters asTHD, MLL, HTLL, TIF and APLC current.
In this study current model of APLC is considered and
hence an 1800 phase shifted harmonic current is to be
injected in the system. The APLC model is considered
as(1)
Where,
Iamh
=
Imaginary
part
Where,
m =1,2, 3, ……………..M Bus numbers.
h=2, 3, 4, 5..................H Harmonic order.
Vbusmh = Voltage in bus m for harmonic order H.
Vbusm1 =Fundamental component of mth bus voltage.
Rmh 1,m 2 =resistance of connection between two buses
m1 and m2.
Z mh 1,m 2 =Impedance of connection between two buses
m1 and m2.
= APLC current
Imh,r = Real part of APLC current
Imh,i
(6)
of
APLC
current
The individual harmonic correctition parameters can
be mathematically stated []as below
 Average harmonic distortion:
Vm ( rms) =RMS bus voltage.
Iamh = APLC current in bus m for harmonic order H.
An 18 bus IEEE standard test bus system for the
(2)
Where
analysis of the allocation and sizing problem has been
taken. The bus system is shown in figure 1. The system
contains 16 buses at 12.5 kV line and 2 busses at 138
kV line.
 Average Motor load loss:
(3)
Where
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Three non linear loads identical to the above
mentioned one are connected in buses 7th 14th and 15th
respectively.
III.PARTICLE SWARM OPTIMIZATION (PSO) AND
In PSO a swarm of random particles (solutions) are
initialized. In this study APLC currents are the particles.
Each particle moves in the given space with some
velocity which is continuously changing in search of
better position. For each particles in its given space OFs
are calculated and the particle corresponding to
minimum/maximum OF is recognized as local
minima/maxima ( Pbest ). Similarly in two successive
iterations
the
OFs
corresponding
to
local
minima/maxima are compared and the particle
corresponding to minimal OF is recognized as global
minima/maxima ( Gbest ). The velocity of all the particles
are updated based on Pbest and Gbest and also based on
new velocity position of the particles are updated. This
process is continued for maximum number of iteration
set or until the converging criteria satisfied. The
mathematical expressions for velocity and position
updating in case of PSO is given bellow -
Vnew  wVid  C1rand ( Pbest  xid )  C2 rand (Gbest  xid ) (
12)
Figure 1: IEEE 18 bus test system
Where,
Vid = velocity of particle i
For analyzing the APLC allocation and sizing
problem a sample nonlinear 3- phase diode rectifier load
is considered and harmonic current produced in the
supply line due to the nonlinear load is analyzed using
Mat-Lab simulation and fast Fourier transform (FFT)
TABLE-1: HARMONIC CURRENTS DUE TO
NONLINEAR LOAD
w =inertia weight factor;
C1 , C2 = random acceleration coefficient
xid =position of particle i
Pbest =best position of particle i
Gbest =best position among all particles
Thus, new position of particle i is
Harmonic
xidnew  xid  Vid
Harmonic current
Order
WEIGHT INERTIA FACTOR:
5th
-0.1998+0.0024*i
7th
-0.1428-0.00049*i
11th
-0.0907-.00079*i
wmax = initial inertia weight factor;
13th
0.0699-0.00024*i
wmin =final inertia weight factor;
17th
0.0586+0.00071*i
ITR =current iteration number;
19th
-0.0526+0.00045*i
w  wmax  {( wmax  wmin ) / ITRmax }* ITR
ITRmax maximum iteration number.
tool. In complex form the harmonic currents are
given in the following table-
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(13)
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TABLE-3: APLC LOCATIONS: Y=YES, X=NO
TABLE-4: OPTIMAL RESULT WITH PSO
Figure 2: Flow Chart for APSO
IV. RESULTS AND DISCUSSION
TABLE-2: INDIVIDUAL AVERAGE HARMONIC
CORRECTION PARAMETERS WITHOUT APLC
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TABLE-5: OPTIMAL RESULT WITH APSO
[3] Singh B. and Al-haddad K., “a review of active
filters for power quality improvement,” ieee trans. Ind.
Electron., vol. 46, no. 5, pp. 960–971, oct. 1999.
[4]
Akagi
H.,
“trends
in
active
power
line
conditioners,” ieee trans. Power electron., vol. 9, no. 3,
pp. 263–268, may 1994.
[5] Ziari I. and Jalilian A., “a new control strategy for
an active powerfilter to compensate harmonics and
reactive power,” presented at theichqp, cascais, portugal,
2006.
[6] Grady W. M. and Samotyj M. J., “the application of
network objectivefunctions for actively minimizing the
impact of voltage harmonics inpower systems,” ieee
trans. Power del., vol. 7, no. 3, pp. 1379–1386,jul. 1992.
[7] Grady W. M. and Samotyj M. J., “minimizing
network harmonicvoltage distortion with an active
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harmonic voltage distortionwith multiple current-
V. CONCLUSIONS
From Table 4 it is seen that in case-10 and case-16 THD
does not come into IEEE-519 standard as given in
paper [15]. However, in case-7 THD, MLL, HTLL
and TIF are minimum, whereas APLC current is large.
In other cases APLC current is large. So case-7 would
be the optimal case for placement of APLC. i.e. in bus
numbers 7 with APLC current of 0.0517 pu.
From Table 5 it is seen that in case-3 and case-12 THD
does not come into IEEE-519 standard. However, in
case-7 THD, MLL, HTLL and TIF are minimum,
whereas APLC current is large. In other cases APLC
current is large. So case-7 would be the optimal case for
placement of APLC. i.e. in bus numbers 7, with APLC
current of 0.0404 pu.
constrained active power
line conditioners,”IEEE Trans. Power Del., vol. 12, no.
2, pp. 837–843, Apr. 1997.
[9] Chang W. K. and Grady W. M., “Controlling
harmonic voltage andvoltage distortion in a power
system with multiple active power lineconditioners,”
IEEE Trans. Power Del., vol. 10, no. 3, pp. 1670–
1676,Jul. 1995.
[10] Keypour R. and Seifi H., “Genetic based algorithm
for active powerfilter allocation and sizing,” Elsevier
Trans. Electrical Power Syst. Res.,pp. 41–49, 2004.
[11] Alrashidi M. R. and El-Hawary M. E., “A survey of
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intelligencecomputation
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Emerging trends in Engineering & Management for Sustainable Development 2016
International conference, Feb 2016
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