International Journal of Engineering & Technology, 7 (3.

10) (2018) 179-183

International Journal of Engineering & Technology

Website: www.sciencepubco.com/index.php/IJET

Research paper

Design and Development of Shunt Active Filter Using MATLAB

for Minimization of Harmonics
Ravi Samikannu1*, R.Rohini2, V.Sampath Kumar3, Vitaliy Mezhuyev4
1
Botswana International University of Science and Technology, Palapye, Botswana
2
Vivekanandha College of Engineering for Women, Namakkal, India
3
Amity University, India
4
University of Malaysia Pahang, Pahang, Malaysia
*Corresponding author E-mail:ravis@biust.ac.bw

Abstract

Nonlinear loads draw non sinusoidal current and voltage from the utility. These non-sinusoidal current and voltages created due to
nonlinear loads are called harmonics. The harmonic voltage and current disturbs the system back and creates big power quality problem.
Therefore in order to mitigate harmonic problems different mechanisms are used. In this work as introduction different power quality
problems, harmonics and their mitigation techniques/filters are presented and discussed. Between the different ways to
minimize/eliminate harmonics active power filters are most Prominent one. This research work presents three phase system shunt active
power filter working based on PQ theory. MATLAB simulation used and results are discussed.

Keywords: Shunt active Power Filter, PQ Theory, Harmonics, Non Linear Load.

resonance. The conventional filters have some disadvantages such

1. Introduction as the fixed compensation, large size and resonance. To overcome
these problems active filters are introduced. The filter is working
for different functions like harmonic filtering, reducing damping,
1.1. Power Quality providing isolation, load balancing. Additionally it is performing
the reactive-power control to achieve power-factor improvement
The distortion of voltage, current and power waveform is called and voltage regulation, reducing the voltage-flicker. Advanced
power quality problem in power system. In recent years, the active filters well advanced in filtering performance with the
developments of power electronics components have great smaller in physical size. The advanced filters are flexible in
advantage in energy conversion and utilization. Power electronics application while it is compared to traditional passive filters using
equipment draws distorted current from the system. As the current inductors and capacitors [3-6].
distortion is conducted through transmission line, it creates
voltage distortion in various parts of the power system. Voltage 1.2. Statement of the Problem
distortion increases because of current distortion has become a
major problem for the utilities at distribution and transmission In earlier days, the harmonic problem in power system created by
levels. Line losses and losses in electrical equipment’s connected magnetic saturation of transformers, and because of industrial
in the transmission system are increased due to the high harmonic loads like arc furnace, arc welding machine. The major concerns
or distortion current flowing through system [1-2]. were the effect of harmonics mainly in the induction and
synchronous machines. Today, however, additional methods for
The harmonics are caused by non-linear loads such as, arc dealing with harmonics are necessary for the following reasons
furnaces, switch mode power supply, fluorescent lamps, rectifiers  Nonlinear loads grow exponentially in recent years in
etc. As a result of these non-linear loads the supply system lead to industrial, commercial and residential areas.
overheating of cables and conductors, electromagnetic  The changes in the increase in the Network resonances.
interference to nearby communication facilities etc. By
 Generally the power system equipment’s and the system
considering the effects of harmonics in various equipment’s in
loads are sensitive to the harmonics.
power system, it is necessary to eliminate these harmonics.
Objective of this study is reducing harmonic distortion, improving
Traditionally, passive filter and capacitor bank are used to filter
system capacity and reliability, energy efficiency using active
the harmonics and compensate the reactive current components
harmonic filter. The industry chosen for the data collection is
due to non-linear loads. They are simple control but very complex
METEC (Hibret manufacturing and tool engineering industry,
under resonant conditions. When the supply voltage waveforms
Ethiopia). The specific objective is reducing the harmonic
are non-sinusoidal, the problems with passive filters are more
distortion and improving the energy efficiency.
pronounced due to the possibility of filter overloading and

Copyright © 2018 Authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
180 International Journal of Engineering & Technology

2. Industry Data Collection and Analysis

2.1. Data Collection

Hibret manufacturing and tool engineering industry receives

15KV power from utility by three 15KV/410V transformers and it
fed to small furnace shop, welding shop and for general services.
The Microvip3 plus power and harmonic analyzer measured all
necessary data’s single phase and three phase of voltage, current,
active power, reactive power, apparent power, power factor, THD.
The measured values of Single phase & three phases Voltage,
current, active, reactive &apparent power is shown in Fig.1. The
THD of L1, L2and L3 for PCC1 is shown in Fig.2. Waveform of
Fig.4: Waveform of voltage and current of L2 for PCC 1
voltage and current is shown in Fig.3, Fig.4 and Fig.5. The total
harmonic distortion analysis is shown in Fig.6, Fig.7 and Fig.8.

Fig.5: Waveform of voltage and current of L3 for PCC 1

Fig.1: Single phase & three phase system Voltage, current,active, reactive
&apparent power for PCC1

Fig.6: THD L1 for PCC1

Fig.2: THD of L1, L2and L3 for PCC1

Fig.3: Waveform of voltage and current of L1 for PCC 1

Fig.7: THD L2 for PCC1

International Journal of Engineering & Technology 181

𝑀𝑉𝐴
Zs = System impedance = 𝑀𝑉𝐴 𝑏 𝑝. 𝑢 (8)
𝑠𝑐

𝐼𝑆𝐶
S.C. Ratio = Short circuit Ratio= 𝐼𝐿
(9)

Where Isc is the short-circuit current at the PCC

Iload is load current at PCC

At bus-bar1 (PCC 1),

Isc/Iload
Full load current of KVA transformer
Isc = (10)
𝑍(𝑖𝑚𝑝𝑒𝑑𝑎𝑛𝑐𝑒)𝑜𝑓𝐾𝑉𝐴 𝑡𝑟𝑎𝑛𝑠𝑓𝑜𝑟𝑚𝑒𝑟

Iload=900A (transformer rating at secondary side)

Z (impedance) of 630KVA = 6%
Iload 900
Isc = Z(impedance)ofKVA transformer=0.06=15000A (11)
Fig.8: THD L3 for PCC1
Isc 15000
= =16.67 (12)
Iload 900
In a power system all the different equipment they are not with
similar ratings they have different ratings. Calculations are used to Table 2:Current Comparison with the standard values
be performed as because the different components and the units are Panel Current distortion Calculation and direct Remark
rated in different format. The percentage values given in the name limits IEEE 519 measurement
nameplates calculated with the respect to the nameplate values Isc/Iload TDD% Isc/Iload TDD%
given. That’s the reason the common base KVA or MVA and also bus- <20 5.0 16.667 14.6 Requires
a base KV is used. The second one is based on the total capacity of bar1 mitigation
a plant or system for base MVA or KVA. The Table.1 shows the (PCC 1)
name plate data of transformer. Table.2 and Table.3 shows the
Table 3: Voltage Comparison with the standard values
current and voltage comparison with the standard values.
Panel Voltage distortion direct measurement Remark
name limits IEEE 519
Table 1: Name Plate Data of the Transformer
Bus TDD% Bus TDD%
Apparent Power (kVA) V1 V2 I1 I2 PL Voltage Voltage
(kv) (V) (A) (A) (W) kV
630 15 410 30.2 900 1500 bus-bar1 <69 5.0 0.41 1.7 Not Requires
(PCC 1) mitigation
𝑀𝑉𝐴𝑏 𝑥103
Ib=Base current in Amps = 𝐴𝑚𝑝𝑠 (1)
√3𝑘𝑉𝑏
3. Proposed System
Percentage reactance,
𝐼𝑋
%𝑋 = 𝑉 𝑥100 (2) 3.1. Shunt Active Power Filter
Where, I=full load current (transformer rating at secondary The Shunt Active Power Filter (SAPF) used to eliminate the
side) harmonic currents. The Active Power Filter (APF) consists of DC
Phase voltage is mentioned as V, reactance in ohms/ Phase is bus capacitor with Voltage Source Inverter with the controlling
X and the short circuit current expressed as, device and inductors. Acting as the current source device and
𝐼∗100
compensating the harmonic current at different nonlinear load
𝐼𝑠𝑐 = %𝑋
(3) conditions. APF is working in the way by generating the
compensating current equal in the magnitude and opposite to the
(or) harmonic produced in the system. This compensation current can
eliminate the harmonics. The VSI switches control the shape of
1000.𝑀𝑉𝐴𝑆𝐶
𝐼𝑠𝑐 = (4) the current. IGBT device is used for the inverter circuit as it is
√3.𝐾𝑉
with high switching frequency. Triggering the inverter circuit
Isc = Short Circuit current at PCC depend on the control circuit system output. P-Q theory is to
derive the compensating signal. The real and reactive power p and
100 q gives the compensating current for the nonlinear load. The
Short Circuit KVA = Base KVA x (5)
%𝑋 active power filtering is to compensating the harmonic currents
which is occurred because of non-linear loads and make sure for
or producing the sinusoidal form of source currents and voltages. The
Fig.9 shows the grid system with shunt active filter. The
Short circuit MVA = √3𝐾𝑉𝑙 𝐼𝑠𝑐 (6) MATLAB simulation for the internal circuit of the shunt active
filter is shown in Fig.10.
Where, ISC is in KA
Where, Base KVA is KVA rating of a single transformer.

Percentage reactance can be expressed in terms of KVA and KV

𝑋.𝐾𝑉𝐴
as, %𝑋 = 10(𝐾𝑉)2 (7)

The ohmic values of R, X, and Z value of the transformer are

182 International Journal of Engineering & Technology

Fig.9: Grid system with shunt active filter

Fig.11: Model for calculation of p-q component

Fig.10: Internal circuit of shunt active filter

3.2. Harmonic Current Extraction Methods

In the active filtering the harmonic currents extraction is to be

injected into the harmonic producing load. The best extraction of
harmonics can be achieved by the efficient power filtering. Based
on the compensating commands by frequency and time domain
techniques the control methods are used. The Fast Fourier
Transform (FFT) in the frequency domain is used to extract the
current harmonics. The time domain methods having a faster
response and it is requiring less calculation with the less memory
use also. Among control methods in time domain, Instantaneous
Fig.12: Shunt active power filter
power (p-q) theory is one and presented in this work. The p-q
theory calculations are carried out in the shunt active power filter.
From phase voltages (va, vb, vc), and load currents (ia, ib, ic) and 4. Simulation Results and Discussion
DC voltage, the controller calculates the reference currents, The
inverter circuit uses reference currents to produce the From this assessment the harmonic disturbance is identified that it
compensation currents. The Fig.11 shows the model calculation of is a big power problem and causes conductor Overheating, reduces
P-Q theory component. The Fig.12 shows the shunt active filter life time of capacitors false or spurious operations and trips of
MATLAB simulation fuses and circuit breakers, increases iron and copper losses or
eddy currents in transformer, , resulting in higher billings to
consumers. Therefore to solve this problem shunt active filter is
designed and simulation has been done. To see the improvement
and compare the previous value with improved one we can see the
results. Based on this before shunt active filter connected to the
system the simulation showed that the THD of current is 17.17%
and this is much greater than 5% the allowable standard by
IEEE. This affects the power system and the machines in the
International Journal of Engineering & Technology 183

industry so has to be mitigated. Based on this shunt active filter is References

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Fig.13: THD before connecting harmonic filter

Fig.14: THD after connecting harmonic filter

5. Conclusion
The proposed system harmonic elimination using shunt active
filter simulated using MATLAB simulation. The results prove that
the proposed system implemented in the distribution system
eliminates the harmonics effectively. The THD analysis for the
current without the active filter is producing an output of 17.17%.
The implemented controller makes the THD value for the current
to 3.7%. The harmonics elimination percentage is around 5%. The
proposed system achieves the goal. The proposed system can be
tested and verified using Microcontroller in real time
implementation. The Artificial techniques like neural network,
Fuzzy logic controller can be implemented to eliminate the
harmonics.