 Open Access
 Total Downloads : 776
 Authors : P. Yuvasri Lakshmi
 Paper ID : IJERTV5IS060330
 Volume & Issue : Volume 05, Issue 06 (June 2016)
 DOI : http://dx.doi.org/10.17577/IJERTV5IS060330
 Published (First Online): 11062016
 ISSN (Online) : 22780181
 Publisher Name : IJERT
 License: This work is licensed under a Creative Commons Attribution 4.0 International License
Power Flow Analysis of Integrated Wind and Solar Power Generation and Distribution System
P. Yuvasri Lakshmi
P.G Student,
Power System Engineering, Kingston Engineering College, Vellore.
Abstract — Power flow analysis is also known as load flow analysis in which per unit voltage and magnitude of the system is analyzed by the MI POWER SOFTWARE using the Newton Naphsion method. Which is faster on the speed of convergence, but programming is more complex suitable for large size system and the number of iterations does not depend on the size of the system, extra retention memory or remembrance is essential. The power flow is not unable to combine parts in power system analysis the main factor incite is the inability regards the power system to meet the demand for reactive power voltage instability does not always occurs in its pure form. A distinction between angle stability is important for understanding the underlying determinant concerning the problem in order to develop appropriate design and operating procedures
Keyword — Load flow analysis; Newton Raphsion method; Extra retention memory; Reactive power voltage instability.

INTRODUCTION
Load flow analysis can be carried out for small and medium size power systems. It suits for the radial distribution system with high R/X ratio. The load flow analysis helps to identify the overloaded/underloaded buses in the system. It is used to study the optimum location of capacity is and their size to improve unacceptable voltage profile Power flow analysis or load flow analysis is performed in a symmetrical steadystate operating condition of a power system under the normal mode of operation. The solution of load flow gives bus voltages and line/ transformer power flow for a prone load condition. This information is essential for longterm planning and operational planning. In the network of the power system, buses become node and a voltage can be specified for each bus. Load flow analysis is essentially concerned with the persistence of complex bus voltages at all busses, given the network configuration and the bus demands. The bus generation and characterized by complex powers flowing into and out of the buses respectively. A generation inventory is nothing but a combination of MW generation of the various generations should match the given requirement plus the transmission losses. It should be noted that there are many generation schedules available to match the prone system demand and one such schedule is chosen for load flow analysis is Newton Raphsion method

CLASSIFICATION OF BUSES
The following information is essential for long term planning and operational planning.

Longterm Planning
Load flow analysis helps in investigating the effectiveness of alternative plans and choosing the perfect plan for system expansion to meet the projected operating state.

Operational planning
It helps in choosing the perfect unit commitment plan and generation schedules to run the system efficiently for the next days load condition without contravening the bus voltages and line flow operating limits.

Steps for load flow analysis
The following work has to be carried for a load flow study. Representation of the system by single line diagram.

Decisive impedance design diagram using the information in the single line diagram

Formation of network equation

Solution of network equation
The buses are classified based on the variable specified. There are three types of buses.

Slack bus or swing bus or reference bus.

Generator bus or voltage bus or PV bus or regulator bus.

Load bus or PQ bus.
The following table gives the quantities specified and the quantities to be specified for each bus
Table I.
S.No
Bus
Quantities Specified
Quantities to be Specified
1.
Slack Bus
V,
P, Q
2.
PV Bus (or) Generator Bus
P,V
Q,
3.
PQ Bus (or) Load bus
P,Q
V,
At these buses, the active and reactive power are specified, the magnitude and phase angle of the voltage are unknown. These are called as load bus
Advantages of load flow analysis
In the power system design and operation there are four things that need to be understand



Slack Bus
In slack bus, voltage magnitude and phase angle of voltages are specified pertaining to a generator bus usually a large capacity generation bus is chosen. We assume voltage (V) as reference phasor
I.e., = 0
Where = Phase angle of voltage.
This bus makes up the difference between the scheduled load and generated power that are caused by the losses in the network.
The power balance equation is

Generation (Type, capacity,forecast and others too)

Distribution network A = cross section area

At 300 metre Resistance R = 0.3021 At 400 metre Resistance R = 0.402 At 200 metre Resistance R = 0.201 At 50 metre Resistance R = 0.0503
H. The Formula to find Reactance
X=XL XC
Where
XC = 1
2
=
=
XL = 2fL
=1
=1
=1
The Formula to find Inductance
P depends on I2 R loss in the transmission line and
L=2l[ ((2) (1 + 1 + ( ) 2))
L
transformer of the network. The individual current in the various lines of the network cannot be calculated until after
1 + ( ) 2 + + ( )]
2
the voltage magnitude and angle are known at every bus of the system. Therefore, PL is initially unknown. Real and reactive power is not specified for slack bus. In power flow
Where
2
4 2
problem,we assume one generator bus as a slack bus at which power generation is Prespecified. After the power flow problem has been solved, the difference between the total specified real power going into the system at all the other buses and the total power consumed by loads plus I2 R losses are assigned to the slack bus. Therefore a generator bus must be selected as the slack bus. The slack bus is needed to account for transmission line losses.

Generator bus or PV bus or Regulated bus
At these buses, the real power and voltage magnitude are specified. The phase angle of the voltage and the reactive power are also specified.
In order to maintain a good voltage profile over the system, Automatic Voltage Regulator (AVR) is used.Static VAR compensator buses are called as buses because real power and voltage magnitude are specified at these buses

Load Bus or PQ Bus

Load (Types of Load, demand and forecast).

Protection


Calculation of Resistance and reactance of system
The Formula to find Resistance (R)
R=
Where
= Resistivity L = Length
d = Diameter
l =length
At 300 m Inductance L = 0.000688H At 400 m Inductance L = 0.000939H At 50 m Inductance L = 0.0000966H At 200 m Inductance L = 0.000442H
Formula for cylindrical Capacitor
C = 2
()
At 300 m capacitance C = 0.0677F
At 400 m capacitance C = 0.0810 F
At 50 m capacitance C = 1.01293×108 F At 200 m cpacitance C = 0.04006 F Reactance of 300 m 0.1638
Reactance of 400 m 0.2556
Reactance of 50 m 0.28363
Reactance of 200 m 0.05933


SINGLE LINE DIAGRAM
A single line diagram is a diagrammatic representation of power system in which the components are represented by their symbols and the interconnection between them are shown by a single straight line (even though the system is a three phase system). The ratings and the impedance of the component are also marked on the single line diagram
20MVa
250 KVa
381.97Kw

Single phase transformer equivalents are shown as ideal transformers with transformer impedance indicated on appropriate side.

Magnetization reactance of the transformers have
0.33021+0.1638
0.402+0.2556j

+0.05933j
Admin
Main Block 109 Kw
0.0503+0.2
63j
0.0503+0.2
63j
E.B
been neglected.

Generator are represented as voltage sources with series resistance and inductive reactance


Steps to draw per unit impedance diagram
83
83

Choose a common MVA or base MVA for the system (Mostly highest generator rating is taken).
110Kw
Hotel Block
250KVa
Block
223.85Kw
110Kw
125KVa
Block
125KVa

Choose an appropriate base KV for each and every section



Applications of Y bus matrix


Ybus is used in solving load flow problems.

It has gained applications owing to the simplicity in data preparation

It can be easily formed and modified for any
changes in the network
Fig. 1. Power system Network
The scope of the single line diagram is to supply in concise form of the significant information about the system. The power system network is represented by one line diagram using suitable symbols for generator, motor, transformer, transmission line and loads.

Impedance diagram
The impedance diagram on the single phase basis under balanced operation conditions can be drawn from one line diagram
Fig. 2. Single Line Diagram

It reduces computer memory and time requirements because of sparse matrix

Y bus is determined by Tworule method or inspection method.In the equivalent network generators are replaced by Nortons equivalent, the load is replaced by equivalent admittances and the lines replaced by equivalent circuits.


LOAD FLOW ANALYSIS RESULT
Load flow analysis is done through newton Raphsion method
Version number: 8.2
%% first power system network
The Largest bus number used 8
Actual number of buses 8
Number of 2 wind. Transformer 2
Number of Transmission lines 5
Number of Loads 4
Number of solar plants 1
Number of Generators 2
Base MVA 50
Nominal system Frequency (Hz) 50
Maximum number of iterations 15
Bus voltage below which load : 0.75 Model is changed
Transformer R/X Ratio : 0.05
Annual percentage interest charges 15
Annual percent operation & 4
Life of equipment I years 20
Maintenance charge
Table I. Bus Data
BUS NO.
AREA
ZONE
BUS KV
VMIN (P.U.)
VMAX (P.U)
NAM E
1
1
1
0.415
0.95
1.05
BUS 1
2
1
1
33.0
.95
1.05
BUS 2
3
1
1
0.69
0.95
1.05
BUS 3
4
1
1
0.415
0.95
1.05
BUS 4
5
1
1
0.415
0.95
1.0
BUS 5
6
1
1
0.415
0.95
1.05
BUS 6
7
1
1
0.415
0.95
1.05
BUS 7
8
1
1
0.415
0.95
1.05
BUS 8
Table II. Transformer Data
STATUS RATING
CKT
FROM NODE
TO NODE
IMPEDENCE
R (P.U.)
X(P.U.)
MINT AP
MAXT AP
3
2
2
3
0.005
0.11765
0.95
1.05
3
2
2
1
0.1061
8
2.12357
0.9105
1
1.00635
Table III. Transformer Data
STATUS RATING
CKT
FROM NODE
TO NODE
NOMINAL TAP
TAP
MVA
TAPSTEP
SHIFT DE
3
2
2
3
0.00588
0.11765
0.95
1.05
3
2
2
1
0.10618
2.12357
0.91051
1.00635
CKT
FROM NODE
FROM NAME
TO
NOD E
TO NAME
RATING MVA
R(P.U)
X(P.U)
1
4
Bus4
1
Bus1
17.88360
10.2560
1
1
Bus1
5
Bus5
17.88360
10.62560
1
1
Bus1
6
Bus6
17.88360
10.62560
1
1
Bus1
7
Bus7
17.88360
10.62560
1
1
Bus1
8
Bus8
17.88360
10.62560
CKT
FROM NODE
FROM NAME
TO
NOD E
TO NAME
RATING MVA
R(P.U)
X(P.U)
1
4
Bus4
1
Bus1
17.88360
10.2560
1
1
Bus1
5
Bus5
17.88360
10.62560
1
1
Bus1
6
Bus6
1.88360
10.62560
1
1
Bus1
7
Bus7
17.88360
10.62560
1
1
Bus1
8
Bus8
17.88360
10.62560
Table IV. Transmission line data

NO OF ITERATION
Iteration count 0 maxp 0.00200 max 0.002945
Iteration count 1 maxp 0.00003 max 0.000022
Iteration count 2 maxp 0.0000 maxq 0.0000
Iteration count 3maxp 0 .0000maxq 0.00000
Iteration count 4 maxp 0.0000 maxq 0.003894
Itertion count 5 maxp 0.00002 maxq 0.000035

The NR method is faster, more reliable and the result are accurate

Required less number of iterations for convergence

The number of iterations are independent of the size of the system

Suitable for large size systems.

Fig. 3. Simulation Single Line Diagram Table V. Bus voltage and Powers
Node No
From name
VMag P.U
Angle degree
MW GEN
1
BUS1
1.0000
0.00
0.017
2
BUS2
1.0088
0.24
0.000
3
BUS3
1.0089
0.25
0.100
4
BUS4
1.0209
0.27
0.050
5
BUS5
0.9716
0.18
0.000
6
BUS6
0.9885
0.07
0.000
7
BUS7
0.9835
0.1
0.000
8
BUS8
0.9885
0.07
0.000
Table VI Bus voltage and Powers
Node No
From name
MVAr GEN
MW LOAD
MVAr LOAD
1
BUS1
0.031
0.000
0.000
2
BUS2
0.000
0.000
0.000
3
BUS3
0.052
0.000
0.000
4
BUS4
0.016
0.000
0.000
5
BUS5
0.000
0.053
0.040
6
BUS6
0.000
0.022
0.017
7
BUS7
0.000
0.031
0.024
8
BUS8
0.000
0.022
0.017
Table VII. Transformer Flow And Transformer Losses
Sl. No
CS
FROM NODE
FROM NAME
TO NODE
TO NAME
FORWARD
MW
MVAr
1
1
2
BUS 2
3
BUS 3
0.100
0.052
2
1
2
BUS 2
1
BUS 1
0.100
0.052
Table VIII.Transformer Flow And Transformer Losses
Sl. No
CS
FROM NODE
FROM NAME
TO NODE
TO NAME
LOSS
MW
MVAr
1
1
2
BUS 2
3
BUS 3
0.0
0.00
2
1
2
BUS 2
1
BUS 1
0.0
0.0005
Table IX. Line Flows And Line Losses
Sl. No
CS
FROM NAME
TO NAME
FORWARD
Loading
MW
MVAr
3
1
BUS 4
BUS 1
0.050
0.016
60.3
4
1
BUS 1
BUS 5
0.055
0.041
80.4
5
1
BUS 1
BUS 6
0.022
0.017
32.5
6
1
BUS 1
BUS 7
0.032
0.024
46.6
7
1
BUS 1
BUS 8
0.022
0.017
32.5


SUMMARY OF RESULTS Total real power generation
(CONVENTIONAL) : 0.00 MW
Tolal reactive power Generation (CONVENTIONAL)
:0.083 MVAr
Toal real power generation (WIND)
:0.100Mw
Total reat. Power generation (WIND)
:0.052MVAr
Total real power generation (WIND)
: 0.050 MW
Total reat. Power generation (SOLAR)
:0.052MVAr
Total real power load : 0.129MW Total real power drawal(ve gen) : 0.017MW Total reactive power load : 0.097MVAr
\
Fig. 4. Output of Simulation Single Line Diagram
Load p.f : 0.8
Total real power loss(AC+DC) : 0.003790 MW
(0.003790+0.0000)
Percentage real loss (AC+DC) : 2.527
Total reactive power loss: : 0.002800MVAr
A. Zone Wise Distribution Description
MW generation : 0.0174
MVAr generation : 0.0312
MW wind gen. :0.1
MVAr wind gen. :0.0517
MW solar gen. :0.0500
MVAr soalr gen. : 0.0164
MW load : 0.1288
MVAr load : 0.0966
MW loss : 0.0038
MVAr loss : 0.0028

CONCLUSION
From the power flow analysis of a given system optimized power flow stabilized which is having
0.1 MW of generation from wind and 0.5MW of generation from solar to the grid connected system of 20 MW of synchronous generator generation. The corresponding voltage and magnitude are stabilized through reactive power compensation and obtianted per unit voltage of given system is also stabilized.
REFERENCE

Power Flow Control using Quadrature Boosters With a suggested Optimal Power Flow Analysis San deep Sadanandan Electrical Engineer Arlington, Virginiasnsadana@yahoo.com Dr. Ghadir Radman Professor of Electrical Engineering, Tennessee Technological University Cookeville, Tennessee

Power Flow Analysis Using Optimal Power Flow Method K. A. Dongre PG Department of Electrical and Electronics Engineering, Prof Ram Meghe College of Engineering and Management, Badnera, Amravati, India dongre_kiran@rediffmail.com A. P. Bhagat PG Department of Computer Science and Engineering, Prof Ram Meghe College of Engineering and Management, Badnera,
Amravati, India amol.bhagat84@gmail.com

Probabilistic Short Circuit Analysis in Electric Power Distribution Systems including Distributed Generation A. Bracale, P. Caramia,

R. Di Fazio, D. Proto 8th Mediterranean Conference on Power Generation, Transmission, Distribution and Energy Conversion MEDPOWER 2012


Wu Ming, 2004, " Solar energy of China equal to ten thousands of Sanxia Projects electrical power ", Population, Resource & Enviroment of China. vol. 16, 6565.

Institute of Electrical Engineering, Chinese Academy of Science, 2001, Acceptance Report of Bange PV station, Beijing, P .R . China.

Yang Xiuxia, Zhang Xiaofeng, 2004, "Present situation and developing trend of isolated power system restoration", Realy, vol. 19, 7479.

Liu Shu, Zhao Zhengming, 2005, "Onelevel photovoltaic grid connected system based on an improved MPPT algorithm", JOURNAL OF TSINGHUA UNIVERSITY(SCIENCE AND TECHNOLOGY, vol. 45, 873876.

Vachtsevanos, G.J. Kang, H, 1989, 1989, "Simulation studies of islanded behavior of gridconnected photovoltaic systems", IEEE Transactions on Energy Conversion, Vol2, 177183.

Asiminoaei. L, Teodorescu. R, Blaabjerg. F, 2005, "A digital controlled PVinverter with grid impedance estimation for ENS detection", IEE ETransactions on Power Electronics, Vol.20, 1480 – 1490] Yu yixin, Wang Chengshan, 2001, Power system stability theory and method Science Press, Beijing, P. R. China.

P.P Varaiya, F.F.Wu, R.L.Chen, 1985, "Direct Methods for Transient Stability Analysis of Power System Recent Results", Proceeding of IEEE, vol.73, 11201125.

Load flows, Chapter 18,Bus classification, Comparison of solution methods, NR methodElectrical Power system by C.L.WADHWA. Stability concept Power Systems Basic Concepts and Applications Part II By ShihMin Hsu, Ph.D., P.E.

Thyristor controlled reactors in flexible AC transmission systems part 1:series compensation by Arindam Ghosh,& Gerard Ledwich F. Sato, A.V. Garcia, A Monticelli: Parallel Implementation of Probabilistic Shortcircuit Analysis by Monte Carlo Approach. IEEE Trans. on Power Systems. Vol. 9, May 1994, pp. 826832.

M.T. Schilling, A.M. Leite da Silva, R. Billinton, M.A. EI Kady:Bibliography on Power System Probabilistic Analysis. IEEE Trans.on Power System, Vol. 5, No. 1, Feb. 1990, pp. 111.

G. Carpinelli, D. Proto, C. Di Perna, P. Varilone, P. Verde:Probabilistic Short Circuit Analysis in Unbalanced Three PhasePower Systems, Proc. of International Conference on Probabilistic Methods Applied to Power System (PMAPS), Sept. 2004, pp.807812.

N. Jenkins, R. Allan, P. Crossley, D. Kirschen, and G. Strbac:
Embedded Generation. London, U.K.; Inst. Elect. Eng. , 2000.

T. E. McDermott and R. C. Dugan: PQ, reliability and DG, IEEE Industry Applications Magazine, Vol. 9, Issue 5, Sep./Oct. 2003, pp. 1723.

S. Hunt and G. Shuttleworth, Unlocking the GRID, IEEE Spectrum, Vol. 33, No. 7, July 1996, pp. 2025.

R Ouiddir, M Rahli & L AbdelhakemKoridak, Economic Dispatch using a Genetic Algorithm: Application to Western Algerias Electrical Power Network Power Systems Optimization Laboratory, Faculty of Electrical Engineering, University of Science and Technology of Oran: Journal of information science and engineering 21, 659668 (2005)

J D WEBER, Implementation of a Newtonbased optimal power flow into a power system simulation environment, thesis submitted at University of Wisconsin Platteville, 1995.

J D Glover & M S Sarma, Power system analysis and design 3rd
Edition, Brooks/Cole, 2002.

J. M. Guerrero, Microgrids: Integration of distributed energy resources into the smart grid, in Proc. IEEE Int. Symp. Ind. Electron.(ISIE), 2010, pp. 42814414.

R. H. Lasseter, Extended CERTS microgrid, in Proc. IEEE Power and Energy Society General MeetingConversion and Delivery of Electrical Energy in the 21st Century, 2008, pp. 15.

C.Marnay, H. Asano, S. Papathanassiou, and G. Strbac, Policymaking for microgrids, IEEE Power Energy Mag., vol. 6, no. 3, pp. 6677, 2008.

C. L.Moreira and J. A. Pecas Lopes, MicroGrids dynamic security assessment,In Proc. Int. Conf.CleanElectrical Power, 2007, pp. 26 32.

M. D. Johnson and R. A. Ducey, Overview of U.S. Army microgrid efforts at fixed installations, in Proc. IEEE Power Energy SocietyGeneral Meeting, 2011, pp. 12.