Distribution Network Power Quality Improvement by D-STATCOM & DVR Under Various Fault Conditions

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056
Volume: 04 Issue: 03 | Mar -2017 www.irjet.net p-ISSN: 2395-0072
© 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 282
Distribution Network Power Quality Improvement by D-STATCOM & DVR
Under Various Fault Conditions
Samrat Shende1, Nilesh Chamat2, Vikki Dhote3
1P.G. Student, Department of Electrical Engineering, BIT, Ballarpur, Maharashtra, India
2Assistant Professor, Department of Electrical Engineering, BIT, Ballarpur, Maharashtra, India
3Assistant Professor, Department of Electrical Engineering, BIT, Ballarpur, Maharashtra, India
Abstract - The concept of Flexible Alternating
Current Transmission Systems (FACTs) and Custom
Power has been researched extensively by researchers
throughout the world and the studies suggest out that
power quality is widely studied by the researchers. On
the whole FACTs uses Power electronic devices and
methods to control the high voltage side of the network
for improving the flow of power. Custom Power Devices
are mainly for low-voltage distribution, and improving
poor quality of power and reliability of supply affecting
entities such as factories, offices and homes. The
quality of Power and Reliability are becoming
important issues for critical and sensitive loads.
DSTATCOM is mainly used to mitigate different faults
such as Single Line to Ground (SLG) fault and Double
Phase to Ground (DPG) fault and three-phase fault. The
fast Response of DSTATCOM makes it the efficient
solution for enhancing the power quality of the
distribution system. DSTATCOM can use with different
types of controllers. In this work, Simulation of
Distribution STATIC Compensator (DSTATCOM) and
DVR has been carried out to improve the quality of
power under different abnormal conditions and results
have been presented through simulations. KEYWORDS:
FACTS, DSTATCOM, DVR, PQ.
Key Words: Introduction1, Related Work2,
Methodology3, Experimental Results4,
Conclusion5, References6
1. INTRODUCTION
Power quality improvement has always been the main
concern of the power engineers and in the recent year with
the increased usage of the digital equipments the power
quality has brought the power quality improvement to a
centre stage. In the present times almost all the industries
use electronic controllers which are extremely sensitive to
the quality of the power to be used. A minor variation
would also lead to serious aberration and may cause the
system to fail. Much of this modern load equipment itself
uses electronic switching devices which then can
contribute to poor network voltage quality. The beginning
of competition into electrical energy supply has created
greater commercial awareness of the issues of power
quality while equipment is now readily available to
measure the quality of the voltage waveform and so
quantify the problem. Along with advancement in
technology, the worldwide economy organization has
evolved towards globalization and the profit margins of
many activities tend to decrease. The increased sensitivity
of the vast majority of processes like (industrial, services
and even residential) to PQ problems turns the availability
of electric power with quality a crucial factor for
competitiveness in every sector of activity. The nonstop
process industry and the information technology services
are most significant area. In a event of even a minor
disturbance the results would lead to a huge amount of
financial loss and consequent loss of productivity and
competitiveness.
2. RELATED WORK
Several studies have been shown that transformer with
automatic tap-changing can be used to improve voltage
stabilities for both steady state and transient state
stabilities. Some of these studies have investigated and are
proposing new models of tap-changing transformers. A
static VAR compensator used to improve the voltage
stability because of the opening line in presence of
induction motor or due to start induction motor or
because recovery of the short circuit IM terminals or due
to the heavy load capacity. With the SVC we can also use
capacitors in series. C. Palanichamy and N. sundar Babu
[14] presented a work on a visual package of educating
preparatory transmission line series compensation. They
presented that the transmission of electrical power over
great distance imposes very sever economical technical
limitations. Here series compensation is very effective in

overcoming such economical technical limitations. Series
compensation technique using capacitors has gained
special interest because of its cost effectiveness. They have
proved two series algorithms using user friendly softwares
package based in visual basics for study of transmission
line series compensation to achieve maximum power
transfer. Matt matele [15] presented a work on enhancing
of transmission capacity of power corriodors by means of
series compensation. K. Ramar & M.S Raviprakash[16]
presented a work on design of compensation of long AC
transmission line for maximum power transfer limited by
voltage stability. They proposed a comprehensive
approach to reactive power management in ac
transmission line for maximum power transfer. The
transmission line presented by its equivalent ߨ model. The
series shunt compensation scheme was separately
analyzed for different load model. Voltage constraint
where taken into consideration during the design of
compensation schemes. A. Leonidaki, G.A. Manos and
N.D.Haziargyrio [17] presented a work on “An effective
method to locate series compensation voltage stabilities
enhancement” they presented that the series
compensation of transmission line is one of the effective
means of increasing the loading margins of an
interconnected power system. In this paper they gave a
methodology for identifying the critical transmission line
with respect to voltage stability issues via sensitivity
analysis. This methodology applies to (N-1) configuration
taking into account future expansion plans taking the
examples of Hellenic interconnected transmission system.
3. METHODOLOGY
DSTATCOM is a voltage source converter (VSC)
that is connected in shunt with the distribution system by
means of a tie reactance connected to compensate the load
current. In general, a coupling transformer is installed
between the distribution system and the DSTATCOM for
isolating the DSTATCOM from the distribution system. 3.1
Isolation transformer: It connects the DSTATCOM to the
distribution network and its main purpose is to maintain
isolation between the DSTATCOM circuit and the
distribution network. 3.2 Voltage source converter: A
voltage source converter consists of a storage device and
devices of switching, generating a sinusoidal voltage at any
required frequency, magnitude and phase angle. In the
DSTATCOM application, this temporarily replaces the
supply voltage or generates the part of the supply voltage
which is absent and injects the compensating current into
the distribution network depending upon the amount of
unbalance or distortion. In this work, an IGBT is used as
the switching device. DC charging unit: This unit charges
the energy source after a compensation event and also
maintains the dc link voltage at the nominal value. 3.3
Harmonic filters: The main function of harmonic filter is to
filter out the unwanted harmonics generated by the VSC
and hence, keep the harmonic level within the permissible
limit. Energy storage unit: Energy storage units like
flywheels, batteries, superconducting magnetic energy
Storage (SMES) and super capacitors store energy.
FIG 1. System scheme of DSTATCOM.
DYNAMIC VOLTAGE RESTORER (DVR)
SYSTEM
Figure 2 depicts a Dynamic Voltage Restorer
(DVR) system with a series insertion transformer
connected between the distribution transformer and the
sensitive load.
Fig.2.Schematic diagram of a dynamic voltage restorer
system
The electrical system viewed from the Point of Common
Coupling (PCC) has been modeled as a 3-phase voltage

source with a short circuit impedance. The DVR can
compensate voltage sags by means of the injection of the
inverter voltage through the series connected transformer
. Essentially, the DVR consist of a series-connected
injection transformer, a voltage source inverter (VSI), a
filter capacitor and an energy-storage device connected to
the inverter DC link. Figure 2 shows the single-phase
equivalent circuit to study the transfer function between
the DVR inverter voltage (VDVR) and the sensitive-load
voltage (VL). Where LT’ and RT’ represent the leakage
inductance of the transformer and its equivalent series
resistance, respectively. Cf is added to make a second-
order filter together with LT’ in order to filter the inverter
output voltage. The voltage supply has been represented
by a voltage source Vswith a short-circuit impedance Rsh
and Lsh in series with a distribution transformer
represented by its leakage inductance (LT) and an
equivalent resistance (RT). The sensitive load has been
modeled by a parallel-connected R-L.
4. EXPERIMENTAL RESULTS
Fig 3 Line voltage
Fig 4 DVR Output
As seen in the figure 4 above we see that the occurrence of
fault the DVR injects voltage into the system to maintain
the power level
Fig 5 STATCOM Output
As seen in the figure 5 above we see that the
occurrence of fault the STATCOM injects current into
the system to maintain the power level
Fig 6 Output voltage
As seen in the output voltage waveform we see that the
DVR comes into play at time duration t= 0.2 to t= 0.4 and
STATCOM comes to play at time t= 0.6 to t =0.7 and thus
the system is able to maintain the power quality
5. CONCLUSION
Distribution networks with static linear and non linear
loads. Proportional-Integral (PI) controller is used with the
device to improve its performance. Test system is analyzed
and results are presented in the simulation section. The
results shows the satisfactory performance of DSTATCOM
in the distribution networks under fault conditions and it
can be concluded that DSTATCOM effectively improves the
power quality in distribution networks with static linear.

As opposed to fundamental frequency switching
schemes already available in the MATLAB/ SIMULINK, this
PWM control scheme only requires voltage measurements.
This characteristic makes it ideally suitable for low-voltage
custom power applications. The simulations carried out
showed that the DVR provides relatively better voltage
regulation capabilities. It was also observed that the
capacity for power compensation and voltage regulation of
DVR and D-STATCOM depends on the rating of the dc
storage device
REFERENCES
[1] Hingorani NG, Gyugyi L (1999) Understanding FACTS.
IEEE Press, New York.
[2] C. Benachaiba, and B. Ferdi “Volage quality
improvement using DVR”,Electrical power quality and
utilization, journa Vol XIV, No.1, pp.39-45, 2008.
[3] Moore P, Ashmole P (1998) Flexible AC transmission
systems. 4. Advanced FACTS controllers. Power Eng J
12(2):95–100
[4] Hadi Saadat, Book on “Power system Analysis,”
McGraw‐ Hill Inc.,US, 1998.
[5] Zhang X-P, Rehtanz C, Pal B (2006) Flexible AC
transmission systems: modelling and control. Springer,
Berlin
[6] Zhang W (2007) Optimal sizing and location of static
and dynamic reactive power compensation. PhD thesis,
University of Tennessee, Knoxville
[7] Nielsen JG, Newman M, Nielsen H, Blaabjerg F (2004)
Control and testing of a dynamic voltage restorer (DVR)
at medium voltage level. IEEE Trans Power Electron
19(3):806–7.1.3.
[8] Meyer C, De Doncker RW, Wei Li Y, Blaabjerg F (2008)
Optimized control strategy for a medium-voltage DVR –
Theoretical investigations and experimental results.
IEEE Trans Power Electron 23(6):2746–2754.
[9] Sankaran.C Book on “Power Quality”, CRC, 2002.
[10] Milanović J. V, Thu A. M and Gupta C. P, “The influence
of fault distribution on stochastic prediction of voltage
sags,” IEEE Trans. Power Del., Vol. 20, No. 1, Jan. 2005,
pp. 278–285.
[11] Milanović J. V and Zhang Y “Modeling of FACT
S Devices for Voltage Sag Mitigation Studies in Large
Power Systems,” IEEE Trans. Power Del., Vol.25, No.4,
Oct. 2010, pp. 3044‐3052.
[12] Haque M. H, “Compensation of distribution system
voltage sag by DVR and D‐STATCOM,” in proceeding of
IEEE Porto Power Tech, Porto, Portugal, Sep. 10–13,
2001.
[13] Choi S.S, Li J.D, and Vilathgamuwa D.M “A generalized
voltage compensation strategy for mitigating the
impacts of voltage sags/swells,” IEEE Trans. Power
Del., Vol. 20, No 3, Jul.
[14] C.Palanichamy, N.S.Babu “A visual package for
educating preparatory transmission line series
compensation”, IEEE Transactions on Education
( Volume: 48, Issue: 1, Feb. 2005 )
[15] M. L. Matele; A. C. Clerici; G. Valtorta "Power
upgrading by converting AC lines to DC “ AFRICON '92
Proceedings., 3rd AFRICON Conference, 1992. [16] K.
Ramar & M.S Raviprakash , “Maximum power transfer
in AC transmission lines limited by voltage stability”,
Proceedings of International Conference on Power
Electronics, Drives and Energy Systems for Industrial
Growth’Year: 1996, Volume: 2
[17] A. Leonidaki, G.A. Manos and N.D.Haziargyrio, “ A
systematic approach for effective location of series
compensation to increase available transfer capability”
2001 IEEE Porto Power Tech Proceedings (Cat
No.01EX502),Year: 2001, Volume: 2
Samrat S. Shende, received the B.E. degree in
Electrical Engineering from the Govt. College of
Engineering, Chandrapur, India, and doing M.Tech. Degree
in Electrical Power System from the Ballarpur Institute of
Technology, Chandrapur, India. His research interests
include a Power Quality, Power Quality Issues and
Enhancement.
Nilesh M. Chamat, received the B.E. degree in
Electrical Engineering from the Govt. College of
Engineering, Chandrapur, India, and M.Tech. Degree in
Electrical Power System from the Walchand College of
Engineering, Sangli, India. He is currently Assiatant
Professor in Ballrpur Institute of Technology, Chandrapur,
India. His research interests include a Power Quality and
Protection
Vikki D. Dhote, received the B.E. degree in Electrical
Engineering from the Govt. College of Engineering,
Chandrapur, India, and M.Tech. Degree in Energy
Management System from Rajiv Gandhi College of
Engineering, Chandrapur, India. He is currently Assiatant
Professor in Ballrpur Institute of Technology, Chandrapur,
India. His research interests include Electrical Machines.

Distribution Network Power Quality Improvement by D-STATCOM & DVR Under Various Fault Conditions

More Related Content

What's hot (19)

Similar to Distribution Network Power Quality Improvement by D-STATCOM & DVR Under Various Fault Conditions (20)

More from IRJET Journal (20)

Recently uploaded (20)

Distribution Network Power Quality Improvement by D-STATCOM & DVR Under Various Fault Conditions