IRJET- A Comparison of Power Quality Improvement based on Controls of UPQC

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 06 Issue: 03 | Mar 2019 www.irjet.net p-ISSN: 2395-0072
© 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1859
A Comparison of Power Quality Improvement based on
Controls of UPQC
M. RAJKUMAR1, Dr M. K. ELANGO2
1PG Scholar Dept.of EEE, K.S.Rangasamy College of Technology, Tiruchengode, Tamilnadu, India
2Professor&Head Dept.of EEE, K.S.Rangasamy College of Technology, Tiruchengode, Tamilnadu, India
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Abstract - This paper proposes compare and analysis of ANN
based unified power quality controller (UPQC) and IRPT for
power quality improvement. The UPQC is the combination of
shunt and series APF. The series APFs are used to compensate
voltage related problems and the shunt APFs are used to
compensate current related problems. The unified power
quality conditioner (UPQC) integrates both shunt and series
APFs through a common DC link capacitor. The UPFC is
employed in power transmission system, and the primary
objective of UPFC is to control the flow of power at,
fundamental frequency. Whereas the UPQC is employed in a
power transmission system. It controls distortion due to
harmonics and unbalance in voltage in addition to control of
flow of power at the fundamental frequency. In this work, the
results obtained through the ANN and IRPT are good in terms
of dynamic response. Simulations are verified by using of
MATLAB/Simulink.
Key Words: Artificial neural network (ANN), Current
Source Inverter (CSI), InstaneousReactivePowerTheory
(IRPT),proportional integral (PI), unified powerquality
conditioner (UPQC), Voltage Source Inverter (VSI).
1. INTRODUCTION
Power quality is one of the major challenges of grid [1]. The
term electric power quality (PQ) is generally used to assess
and to maintain the good quality of puissance at the caliber
of generation, transmission, distribution, and utilization of
AC electrical potency. Since the pollution of electric power
supply systems is much astringent at the utilization level, it
is paramount to study at the terminals of end users in
distribution systems. There are a number of reasons for the
pollution of the AC supply systems, including natural ones
such as lightening, flashover, equipment failure, and faults
(around 60%) and coerced ones such as voltage distortions
and notches (about 40%). A number of customer’s
equipment additionally pollute the supply system as they
draw non sinusoidal current andcomportasnonlinearloads.
Ergo power quality is quantified terms of voltage, current or
frequency deviation of the supply system, which may result
in failure or mal-operation of customer’s equipment.
Typically, some power quality quandaries cognate to the
voltage at the point of prevalent coupling (PCC) [2] where
sundry loads are connected are the presence of voltage
harmonics, surge, spikes, notches, sag/dip, swell,unbalance,
fluctuations, glitches, flickers, outages, and so on. These
quandaries are present in the supply system due to sundry
perturbances in the system or due to the presence of sundry
nonlinear loads such as furnaces, uninterruptible power
supplies (UPSs), and adjustable speed drives (ASDs).
However, some power quality quandaries cognate to the
current drawn from the AC mains are impecunious power
factor, reactive power burden, harmonic currents,
unbalanced currents, and an exorbitant neutral current in
polyphase systems due to unbalancing and harmonic
currents engendered by some nonlinear loads. Electrical
equipment susceptible to power quality or more
congruously to lack of potency quality would fall within a
ostensibly abysmal domain. Mundane issues cognate to
power quality are such as voltage sag, voltage swell, voltage
unbalance, harmonics, voltage fluctuations. General issues
cognate to power quality are such as voltage sag, voltage
swell, voltage unbalance, harmonics, voltage fluctuations.In
this paper, the instantaneous reactive power theory is
presented, and its emolument strategy is applied to a three
phase three-wire power system.
2. UNIFIED POWER QUALITY CONDITIONER
UPQC is a coalescence of a shunt active power filter and
series active power filter. here shunt active power filter
(APF) is utilized to compensate for load current harmonics
and make the source current thoroughly sinusoidal and
liberate from harmonics and distortions. Shunt APF is
connected parallel to transmission line. Here series APF is
utilized to mitigate for voltage distortions and unbalance
which is present in supply side and make the voltage at load
side impeccably balanced, regulated and sinusoidal. Series
APF is connected in series with transmission line.
2.1 CONFIGURATION OF UPQC
The configuration of UPQC is shown in Figure 1 in general
UPQC is a power conditioner device which consists of two
voltage sourceinverters(VSI)connectedthrougha prevalent
dc-link capacitor
Fig-1: Configuration of UPQC

It is utilized to mitigate both load current as well as supply
voltage imperfections. The main components of a UPQC are
series converter and shunt converter, dc capacitors,lowpass
and high-pass passive filters, and series and shunt injecting
transformers. The purport of a UPQC is to compensate for
supply voltage power quality issues, such as sags, swells,
unbalance, flicker and harmonics.
3. REFERENCE SIGNAL GENARTION FOR UPQC
In this work two controls for Unified Power Quality
Conditioner has been implemented and detailed study has
been carried based on the compensation of voltage, current
and harmonics
3.1 INSTANTANEOUS REACTIVE POWER THEORY
The instantaneous reactive power theory, withal designated
p–q formulation is predicated on the Clarke coordinates
transformation, which, applied to the voltage and current
vectors in phase coordinates, gives those vectors in 0αβ
coordinates In instantaneous power theory, the
instantaneous three phase currents and voltages are
calculated as given in following equations 3 and 4
The 𝛼 − 𝛽 theory is one of several methods that can be
utilized in the control active filters. It presents some
intriguing features, namely,
• It is inherently a three-phase system theory
•It predicatestheinstantaneousvalues,sanctioning excellent
dynamic replication
• It can be applied to any three-phase system (balanced or
unbalanced, with or without harmonics in both voltagesand
currents)
The instantaneous active and reactive power in the 𝛼 − 𝛽 − 0
coordinates are calculated with the following expressions
Where the P0, P, Q are the instantaneous zero sequence
power, instantaneous real power, instantaneous imaginary
power.
3.2 ARTIFICIAL NEURAL NETWORK
The detection of the disturbance signal in a rapid way with
high accuracy, fast processing of the reference signal, and
high dynamic response of the controller are the prime
requirements for desired compensationincaseofUPQC. The
traditional controller neglects to perform agreeably under
parameter varieties nonlinearity load aggravation, and so
forth. An ongoing report demonstrates that NN-based
controllers give quick unique reaction while keeping up
steadiness of the converter framework over wide working.
Neural systems are models of natural neural structures. The
beginning stage for most neural systems is a model neuron,
as in Figure 2. This neuron comprises of variousinformation
sources and a solitary output. Each information is changed
by a weight, which increases with the info esteem. The
neuron will join these weighted sources of info and, with
reference to an edge esteem and actuation work, utilize
these to decide its output. The conduct pursues intently our
comprehension of how genuine neuronswork.ANN benefits
include massive parallelism, learning faculty, generalisation
faculty, adaptivity, expeditious convergenceandrobustness.
Fundamental ANN architecture has 3 layers and is shown in
Fig. 2. Contextual information processing, Fault tolerance,
low energy consumption, tracking faculty
Fig-2: Basic structure of ANN
1. Input layer — stores input data and withal inputsto
be given to the system are provided through this layer.
2. Hidden layer — inputs provided by input layer are
processed in this layer depending on weights of connection
between layers, partialness if any and activation function.
3. Output layer — results of the computations are
stored.
ANN is one of the AI techniques which find very opportune
application to power electronicsystemcontrol.Recentstudy
denotes controllers designed predicated on ANN provides
more expeditious dynamic replication and ameliorated
stability of converter systems over wide range of operating
conditions.
……………….5
……………….6
……………….7
……………….3
……………….4

4. SIMULATION WORK AND RESULT
The system is simulated based on following parameter as
shown in table 1
Table -1: System parameter
Fig-3: Simulink Model of UPQC
MATLAB is an interactivesystemfornumerical computation.
The simulation diagram of unified Power Quality
Conditioner is shown below in fig 3 The system has been
simulated based on flowing parameter shown in table 1for
both IRPT and ANN controller. The system is simulated at
the intervals of 0.8 to 1.6 during this sag and swell arecrated
and waveforms are obtained which have been shown on
table 2
Table -2: output values
Terms Without
UPQC
With IRPT With ANN
Voltage 0.8 to 1.6 Reduce
upto 0.85
Reduce
upto 0.87
Current 0.8 to 1.6 Reduced
upto 0.85
Reduced
upto 0.88
Harmonics 9.56% 0.4% 0.41%
Here from above table 2 we have obtained that upqc with
IRPT has the best output compared with ANN controllerand
without conditioner.
4.1 Voltage Waveform
Before connecting UPQC:
Here the voltage wave form is obtained and it has been
simulated in time interval 0.8 to 1.6 sec as shown in fig 4
Fig-4: voltage wave before connecting UPQC
After connecting UPQC(IRPT):
Here the voltage wave form is obtained the distoritaion is
reduced upto 0.85sec from 1.6 sec by implementing IRPT as
shown in fig 5
Fig-5: voltage wave after connecting UPQC
After connecting UPQC(ANN):
Here the voltage wave form is obtained the distoritaion is
reduced upto 0.87sec from 1.6 sec by implementing IRPT as
shown in fig 6
Fig-6: voltage wave after connecting UPQC
4.2 Current Waveform
Before connecting UPQC:
Here the current wave form is obtained swell are present in
the time interval of 0.8 to 1.6 sec as shown in fig 7
Fig-7: current wave before connecting UPQC
B After connecting UPQC(IRPT):
Here the current wave form is obtained swell are reduce
upto 0.85sec from 1.6 as shown in fig 8
Types Range
Three phase source 110Kv
Three phase transformer 110/33 Kv
Inductor 4e-3H
Series transformer 250e-6KVA
Non liner RL load --

Fig-8: current wave after connecting UPQC
C After connecting UPQC(ANN):
Here the current wave form is obtained swell are reduce
upto 0.88 sec from 1.6 by implementing ANN control as
shown in fig 9
Fig-9: current wave after connecting UPQC
4.3 Harmonic Distortion
The Harmonic distortion in the system is analysed in source
side. The THD in source side before connecting UPQC
is9.56% at the time of 0.84 sec and THDisanalysedinsource
side after connecting UPQC(IRPT) is 0.4% at the time of0.86
sec as shown below fig 10 ,fig 11 and THD is analysed in
source side after connecting UPQC(ANN) is 0.41% at the
time of 0.86 sec
Fig-10: THD Without UPQC
Fig-11: THD With UPQC(IRPT)
Fig-12: with UPQC(ANN)
5. CONCLUSION AND FEATURE SCOPE
In this paper the incrementation in commercial and
industrial load has results in rigorous power quality
quandary in the transmission and distribution side. The
major perturbance in the distribution side cause losses of
equipment, damage equipment. To solve these quandaries
several solutionshavebeendevelopedandcumulatedpower
quality conditioner is the one of the most popular solution
used nowadays. In these work it has been conclude that
,both ANN control and IRPT control strategyhavebeenused
which results reductionofharmonicsandpowerdisturbance
etc for the operation of Power system out of both IRPT has
the better result compared with other controller . Furtherly
this work can be elongate in the controller performance of
active filter may further be specified by other perspicacious
control techniques like Genetic algorithm. These control
techniques which reduce the uncompensated part and
improve the power quality compared with previous control
techniques
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