Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
AN ANALYTICAL STUDY OF ENHANCEMENT OF POWER QUALITY USING DVR
Mandadi Surender Reddy,
Research Scholar, Department of EE, Sunrise University, Alwar,Rajasthan
Dr. Dalvinder Kaur Mangal, Supervisor, Department of EE, Sunrise University, Alwar,Rajasthan
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ABSTRACT
The Power Quality Analysis tries to bring out electricity customers for upgraded power quality
with utilization of power gadgets. The investigation work incorporates through and through
analysis of the collaboration among loads, power systems and diverse power quality change
gadgets. It in the end prompts better framework of alleviation gadgets like Dynamic Voltage
Restorer (DVR), Distribution Static Synchronous Compensator (DSTATCOM) and Unified
Power Quality Conditioner (UPQC) to help diverse power quality related issues. The standard
objective of this suggestion is to develop a model of DVR, DSTATCOM and UPQC for
development of power quality. DVR is one of the custom power gadgets that are used as a
reasonable response for the insurance of delicate burdens against voltage agitating impacts in
power circulation system. The capability of the DVR depends upon the execution of the control
technique, which related with trading the inverters. While modifying, the transient response of
the DSTATCOM is basic for non linearly contrasting and uneven burdens. The DC Link voltage
is extended over the reference esteem when the stack is out of the blue removed and it is reduced
underneath its reference esteem exactly when the load is out of the blue extended. Customarily, a
Proportional Vital (PI) controller is used to keep up the DC Link voltage at the reference esteem.
INTRODUCTION
At present, modern industrial devices are
normally in view of power electronic
devices, for example, programmable logic
controllers and customizable speed drives.
The electronic devices are exceptionally
receptive to unsettling influences and turn
out to be less tolerant to power quality
issues, for example, voltage sags, swells and
harmonics. Voltage plunges are thought to
be a standout amongst the most serious
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
unsettling influences to the industrial
equipments.
DVRs are a class of custom power devices
for giving steady dissemination power
quality. They utilize a progression of voltage
support innovation utilizing strong state
switches for remunerating voltage
sags/swells. The DVR applications are for
the most part for touchy burdens that might
be impressively influenced by fluctuations
in system voltage.
LITERATURE REVIEW
DVR system in perspective of downstream
accuse compelling limit and a transition
charge indicate criticism controller has been
proposed and fused by Yun Wei Li et al.
Detail of the healthiness and mix up
following execution considered for authentic
assurance of weighting capacities. Critical
increases at positive and negative line
frequencies affected with the tuning of
coordinated H∞ controller. Thus the positive
and negative grouping segments would
enough immediate. H∞ voltage circle and
internal current circle is arranged and
embedded by Yun Wei Li et al.
For the compensation of power quality
issues viz. voltage hangs, voltage harmonics
and voltage unpredictable qualities a two
level DVR with dull controller was
displayed by Pedro Roncero-Sanchez et al.
To reduce the voltage hangs and control the
DC Link voltage, a course of action
compensating device which is transformer
less self charging DVR was depicted by Eng
Kian Kenneth SNG Et Al. They found that
the cost and size of the device can be
reduced due to the transformer
nonattendance. The DC Link voltage
heading instrument smoothens in light of
channel inductor vitality.
Constant state analysis based DVR was
appeared by Arindam Ghosh and Gerard
Ledwich . Time fluctuating reference
voltages of a DVR can be overcome
different decisions. VSI is used to
comprehend the structure of the DVR.
A DVR is proposed in light of power
mastermind analysis, a joined feed forward
and state input control structures for the
compensation of voltages. Basic framework
rules viz. control delay and channel cutoff
repeat are similarly proposed for the
controller of a DVR system was proposed
by Hyosung Kim Seung-Ki Sul.
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
BASIC CONFIGURATION OF DVR
The basic setup of the DVR comprises of the
accompanying fundamental units.
1 An Injection/ Booster
transformer
2 A Harmonic filter
3 Storage Devices
4 A Voltage Source Converter
5 DC charging circuit
6 A Control and Protection
system
Injection/ Booster Transformer
The Injection/Booster transformer is an
especially composed transformer that
endeavors to confine the coupling of noise
and transient energy from the essential side
to the secondary side. Its significant errands
are given beneath.
Figure 1 Schematic Diagram of DVR
Voltage Source Converter
A VSC is a power electronic system
comprises of a storage device and
exchanging hardware, which can deliver a
sinusoidal voltage at any important
frequency, magnitude and phase angle. In
the DVR application, the VSC is utilized to
quickly supplant the supply voltage or to
create the piece of the supply voltage which
is absent.
DC Charging Circuit
The dc charging circuit has two main tasks.
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
1 The first task is to charge the
energy source after a sag
compensation event.
2 The second task is to
maintain DC Link voltage at
the nominal DC Link voltage.
Equations related to DVR
The load impedance Zth relies upon the
blame level of the load transport. At the
point when the system voltage (Vth) drops,
the DVR infuses a seriesvoltage VDVR
through the injection transformer with the
goal that the coveted load voltage magnitude
VL can be kept up. The arrangement infused
voltage of the DVR can be composed as
(1)
Where
VL: The desired load voltage magnitude
ZTH: The load impedance.
IL: The load current
VTH: The system voltage during
fault condition The load current
IL is given by,
(2)
When VL is considered as a reference
equation can be rewritten as,
(3)
Are angles of VDVR, ZTH ,VTH
respectively and is Load power angle The
complex power injection of the DVR can be
written as,
(4)
It requires the injection of just reactive
power and the DVR itself is fit for
producing the reactive power.
SIMULATION OF DVR WITH PI
CONTROLLER AND FUZZY LOGIC
CONTROLLER
Computer simulation has turned into a key
piece of the power electronics design
process. DVR is a power electronics device
which comprises of voltage source converter
as a critical element. The general design
process can be abbreviated using computer
simulations, since it is typically less
demanding to examine the impact of a
parameter on the system conduct in
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
simulation. Primary system simulation
model without DVR has been made in
Matlab/Simulink:
Figure 2 Main Systems without DVR
To check the working of a DVR utilized to
evade voltage sags amid hamper, a
resistance of 0.4 Ω. Such fault is connected
for 400msec. The limit of the dc storage
device is 5 kV.
Figure 3 PI Controller subsystems
The test system of without DVR amid faults
like three phase fault, single line to ground
fault and twofold line fault is investigated.
Watched load voltage issues like sag, swell
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
and interruption. At that point to beat these
issues DVR is associated for the test system
notwithstanding the controllers like PI
Controller with parameters KP = 0.5, Ki =
50 and test time 50µsec and Fuzzy Logic
Controller for the upgrade of the execution
and THD change.
Figure 4 Main diagram of DVR with Fuzzy Logic Controller
Simulation Results for Voltage Sag
during Three Phase Fault
The principal test system contains no DVR
and a three-phase circuit fault is connected,
by means of a fault resistance of 0.4ω, amid
the period 500 to 900ms. The load voltage is
35% as for the reference voltage. Fig. 4.14
demonstrates the RMS load voltage sag at
the RL load (R = 10ω and L = 10-6H) for
the situation when the system works with no
DVR.
The second test system is completed
utilizing an indistinguishable situation from
above however now DVR with PI Controller
and DVR with Fuzzy Logic Controller are in
operation. The aggregate simulation time
frame is 1400 ms. At the point when the
DVR is in operation the voltage sag is
moderated totally and the rms voltage of the
delicate load is kept up at 98% while DVR
with FLC as appeared in Fig. 4.15 with the
limit of the dc storage device is 5 kV.
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
Figure 5 Voltage VRMS at the load without DVR
The PWM control conspires controls the
magnitude and the phase of the infused
voltages, reestablishing the RMS voltage
viably. The sag moderation is performed
with a smooth, steady and fast DVR
reaction. Two transient undershoots are
watched when the DVR comes all through
operation. It ought to be noticed that in the
DVR, the dc voltage is provided by a dc
capacitor. A few simulations were
completed to evaluate the execution of the
DVR as a component of short out closeness
and the remuneration ability of DVR relies
upon the limit of the energy storage device.
Fig. 4.16 and Fig. 4.17 demonstrate that the
repaying ability of DVR relies upon the
limit of the DC energy storage.
Simulation Results for Voltage Sag
during Single Line to Ground Fault
The principal test system contains no DVR
and a solitary line to ground fault is
connected and the comparing waveform as
appeared in Fig. 4.18, through a fault
resistance of 0.2 Ω, amid the period 500 to
900 ms. the voltage sag at the load voltage is
30% concerning the reference voltage. The
second test system is done utilizing an
indistinguishable situation from above
however now DVR with PI Controller and
DVR with Fuzzy Logic Controller are in
operation. The aggregate simulation time
frame is 1400 ms.
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
Figure 6 Voltage VRMS at the load without DVR
Simulation Result of Voltage Sag during
Double Line Fault
The primary test system contains no DVR
and a twofold line fault is connected through
a fault resistance of 0.1 Ω, amid the period
500 to 900 ms. the voltage sag at the load
voltage is 65% concerning the reference
voltage. Fig. 4.23 demonstrates the RMS
voltage at the load point for the situation
when the system works with no DVR. The
second test system is done utilizing an
indistinguishable situation from above yet
now DVR with PI Controller and DVR with
Fuzzy Logic Controller are in operation. The
aggregate simulation time frame is 1400
ms.\
Figure 7 Voltage VRMS at the load without DVR
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
Simulation Result of Voltage Interruption
during Three- Phase Fault
The primary test system contains no DVR
and three phase fault is connected by means
of a fault resistance of 0.001 Ω, amid the
period 500 to 900 ms. The voltage at the
delicate load is 0% concerning the reference
voltage. Fig. 4.28 demonstrates the RMS
voltage at the load point for the situation
when the system works with no DVR.The
second test system is done utilizing an
indistinguishable situation from above
however now DVR with PI Controller and
DVR with Fuzzy Logic Controller are in
operation. The aggregate simulation time
frame is 1400 ms.\
Figure 8 Voltage VRMS at the load without DVR
CONCLUSION
DVR is an as of late proposed arrangement
associated solid state device that infuses
voltage into the system with a specific end
goal to manage the heap side voltage. It is
typically introduced in a dissemination
system between the supply and the basic
load feeder at the purpose of regular
coupling. Other than voltage sags and swells
compensation, DVR can likewise included
different components, those are line voltage
harmonics compensation, diminishment of
transients in voltage and fault current
impediments and afterward investigate the
dynamic and unfaltering state execution of
Airo International Research Journal March, 2016 Volume VII, ISSN: 2320-3714
DVR. The consequences of voltage and
current waveforms of DVR utilizing PI
Controller and Fuzzy Logic Controller with
voltage list amid three stage fault, voltage
list amid single line to ground fault, voltage
hang amid twofold line fault, voltage
interruption amid three stage fault and
voltage swell focuses are broke down. DVR
with Fuzzy Logic Controller performs better
among DVR with PI Controller and Fuzzy
Logic Controller.
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