Load Flow Analysis of IEEE-3 bus system by using Mipower Software

Load Flow Analysis of IEEE-3 bus system by using Mipower Software

Sandeep kaur1 Amarbir Singp Dr. Raja Singh Khela3

1 Asst. Professor, 2Asst.Professor, 3Director,

Department of Electrical & Electronics Engg, Department of Mechanical Engineering, Jasdev Singh Sandhu Institute of Engg & Tech

Chandigarh University,Gharuan(Mohali),Punjab Chandigarh University,Gharuan(Mohali),Punjab (Patiala), Punjab

Abstract The load flow study or power flow analysis is very important for planning, control and operations of existing systems as well as planning its future expansion. The satisfactory operation of the system depends upon knowing the effects of interconnections, new loads, new generating stations or new transmission lines etc., before they are installed. It also helps to determine the best size and favorable locations for the power capacitors both for the improvement of the power factor and also raising the bus voltage of the electrical network. They help us to determine the best locality as well as optimal capacity of the proposed generating stations, substations or new lines.

1. For this work the gauss-seidel method is used for numerical analysis.Nowadays Mipower software is used for load flow studies.This type of analysis is useful for solving the power flow problem in different power systems which will useful to calculate the unknown quantities.

   Keywords-Power flow analysis, Power capacitors, Optimal capacity ,Guass-siedel method,Mipower software

   .

   • Generator bus or voltage controlled bus: Here the voltage magnitude corresponding to the generator voltage and real power Pg corresponds to its rating are specified. It is required to find out the reactive power generation Qg and phase angle of the bus voltage.

   • Slack (swing) bus: For the Slack Bus, it is assumed that the voltage magnitude |V| and voltage phase are known, whereas real and reactive powers Pg and Qg are obtained through the load flow solution

1. INTRODUCTION

   The Load flow problem consists of calculation of voltage magnitude and its phase angle at the buses. And also the active and reactive lines flow for the specified terminal or bus conditions.

   Load flow studies are used to ensure that electrical power transfer from generators to consumers through the grid system is stable, reliable and economic. Conventional techniques for solving the load flow problem are iterative, using the Newton-Raphson or the Gauss-Seidel methods. Depending upon the quantities specified for the buses, they are classified into three types namely load bus,generator bus or voltage controlled bus and slack bus or swing bus or reference bus.

2. BUS CLASSIFICATION

   Buses are classified according to which two out of the four variables are specified

   • Load bus: No generator is connected to the bus. At this bus the real and reactive power are specified and it is desired to find out the volatage magnitude and phase angle through load flow solutions.It is required to specify only Pd and Qd at such bus as at a load bus voltage can be allowed to vary within the permissible values.

   Fig.1 Bus classification

3. SOLUTION METHODS

   The solution of the simultaneous nonlinear power flow equations requires the use of iterative techniques for even the simplest power systems.

   There are many methods for solving nonlinear equations, as shown in Fig.2

   F

   ig.2 Types of Load flow methods

4. IEEE 3 BUS SYSTEM STABILITY

   Figure shows a single line diagram of a 3 bus system with two generating units, three lines. Perunit transmission line series impedances and shunt susceptances are given on 100 MVA base in Real power generation, real and reactive power loads in MW and MVAR are give. Conduct the load flow analysis..

   Assume the base voltage for the bus as 11 kV and system frequency as 50 Hz.

   Impedances and line charging for the system

   Table : 1.1
   Bus code From – To	Admittance Ypq	Line charging Ypq/2
   1-2	1.47+j5.88	J0.015
   1-3	2.94-j11.77	j0.07
   2-3	2.75-j9.17	j0.04

   Generation, loads and bus voltages for the system

   Transmission Line Element Data

   Line No	From Bus	To Bus	No. of circuits	Structure Ref. No.
   2	1	3	1	2
   3	2	3	1	3

   Bus code No	Intertia(H)	Xd
   1	160	0.1
   2	3	0.3

   Line and cable Library

   Table : 1.2
   B us N o	Bus Voltage	Generat ion MW	Generation MVAR	Load MW	Load MVA R
   1	1.04+j0.0	0	0	0	0
   2	1.02+j0.0	100	—	50	20
   3	1.00+j0.0	0	0	250	150

   Generator Data

   Load Flow Analysis

   Load flow studies

   Load flow analysis taken here for case study of IEEE-3 bus system. The network shown in Figure-3 a single line diagram is prepared using Mi-Power software.Execute load flow analysis and click on Report in load flow analysis dialog to view report.

5. SUMMARY OF RESULTS:

   ———————————————————–

   –

   Date and Time : Fri Oct 17 12:23:30 2014

   ———————————————————–

   –

   LOAD FLOW ANALYSIS

   CASE NO : 1 CONTINGENCY : 0 SCHEDULE NO : 0

   CONTINGENCY NAME : Base Case RATING CONSIDERED : NOMINAL

   ———————————————————–

   –

   VERSION NUMBER : 7.3

   %% First Power System Network

   LARGEST BUS NUMBER USED : 3 ACTUAL NUMBER OF BUSES : 3 NUMBER OF 2 WIND. TRANSFORMERS :

   0 NUMBER OF 3 WIND. TRANSFORMERS

   : 0

   NUMBER OF TRANSMISSION LINES : 3 NUMBER OF SERIES REACTORS : 0 NUMBER OF SERIES CAPACITORS : 0 NUMBER OF CIRCUIT BREAKERS : 0 NUMBER OF SHUNT REACTORS : 0 NUMBER OF SHUNT CAPACITORS : 0 NUMBER OF SHUNT IMPEDANCES : 0 NUMBER OF GENERATORS : 2 NUMBER OF LOADS : 2

   NUMBER OF LOAD CHARACTERISTICS :

   0 NUMBER OF UNDER FREQUENCY RELAY: 0NUMBER OF GEN CAPABILITY CURVES: 0 NUMBER OF FILTERS

   : 0

   NUMBER OF TIE LINE SCHEDULES : 0 NUMBER OF CONVERTORS : 0 NUMBER OF DC LINKS : 0 NUMBER OF SHUNT CONNECTED FACTS: 0

   POWER FORCED LINES : 0

   NUMBER OF TCSC CONNECTED : 0 NUMBER OF SPS CONNECTED : 0 NUMBER OF UPFC CONNECTED : 0

   ———————————————————–

   ——————–

   LOAD FLOW – FAST DE-COUPLED TECHNIQUE : 0

   NUMBER OF ZONES : 1

   PRINT OPTION : 3 –

   BOTH DATA AND RESULTS PRINT

   PLOT OPTION : 1 –

   PLOTTING WITH PU OLTAGE

   NO FREQUENCY DEPENDENT LOAD FLOW, CONTROL OPTION: 0

   BASE MVA :

   100.000000

   NOMINAL SYSTEM FREQUENCY (Hzs)

   : 50.000000

   FREQUENCY DEVIATION (Hzs)

   : 0.000000

   FLOWS IN MW AND MVAR, OPTION

   : 0

   SLACK BUS : 0

   (MAX GENERATION BUS)

   TRANSFORMER TAP CONTROL OPTION

   : 0

   Q CHECKING LIMIT (ENABLED)

   : 4

   REAL POWER TOLERANCE (PU)

   : 0.00100

   REACTIVE POWER TOLERANCE (PU)

   : 0.00100

   MAXIMUM NUMBER OF ITERATIONS

   : 15

   BUS VOLTAGE BELOW WHICH LOAD MODEL IS CHANGED : 0.75000

   CIRCUIT BREAKER RESISTANCE (PU)

   : 0.00000

   CIRCUIT BREAKER REACTANCE (PU)

   : 0.00010

   TRANSFORMER R/X RATIO : 0.05000

   ———————————————————–

   ——————-

   ANNUAL PERCENTAGE INTEREST CHARGES : 15.000

   ANNUAL PERCENT OPERATION & MAINTENANCE CHARGES : 4.000

   LIFE OF EQUIPMENT IN YEARS

   : 20.000

   ENERGY UNIT CHARGE (KWHOUR)

   : 2.500 Rs

   LOSS LOAD FACTOR : 0.300

   COST PER MVAR IN LAKHS :

   5.000 Rs

   ———————————————————–

   ——————–

   ZONE WISE MULTIPLICATION FACTORS ZONE P LOAD Q LOAD P GEN Q GEN SH REACT SH CAP C LOAD

   —- ——– ——– ——– ——– ——– ——– —

   ——

   0 1.000 1.000 1.000 1.000 1.000

   1.000 1.000

   1 1.000 1.000 1.000 1.000 1.000

   1.000 1.000

   ———————————————————–

   ——————– BUS DATA

   BUS NO. AREA ZONE BUS KV VMIN-PU VMAX-PU NAME

   ——- —- —- ——– ——– ——– ——–

   1 1 1 11.000 0.950 1.050 Bus1

   2 1 1 11.000 0.950 1.050 Bus2

   3 1 1 11.000 0.950 1.050 Bus3

   ———————————————————–

   –

   TRANSMISSION LINE DATA

   STA CKT FROM FROM TO TO LINE PARAMETER RATING KMS kV

   NODE NAME* NODE NAME* R(P.U) X(P.U.) B/2(P.U.) MVA

   — — —- ——– —- ——– ——— ——— —–

   –

   3

   0

   2 3 Bus3 50.000 20.000 0.000 0.000

   100.000 1.000 0 0

   3

   0

   ———————————————————–

   –

   TOTAL SPECIFIED MW GENERATION : 450.00000

   TOTAL MIN MVAR LIMIT OF GENERATOR

   : 140.00000

   3 1	1 Bus1	2	Bus2	0.04000	TOTAL MAX MVAR LIMIT OF
   0.16006	0.15000 250	1.0			GENERATOR : 235.83100
   3 1	1 Bus1	3	Bus3	0.01000	TOTAL SPECIFIED MW LOAD :
   0.08000	0.07000 250	1.0			300.00000 reduced 300.00000
   3 1	2 Bus2	3	Bus3	0.03000	TOTAL SPECIFIED MVAR LOAD :
   0.10000	0.04000 250	1.0			170.00000 reduced 170.00000

   ———————————————————–

   ———————————————————–

   –

   TOTAL LINE CHARGING SUSCEPTANCE

   : 0.52000

   TOTAL LINE CHARGING MVAR AT 1 PU VOLTAGE : 52.000

   ———————————————————–

   –

   TOTAL CAPACITIVE SUSCEPTANCE : 0.00000 pu – 0.000 MVAR

   TOTAL INDUCTIVE SUSCEPTANCE : 0.00000 pu – 0.000 MVAR

   ———————————————————– GENERATOR DATA

   SL.NO* FROM FROM REAL Q-MIN Q-MAX V-SPEC CAP. MVA STAT

   NODE NAME* POWER(MW) MVAR MVAR P.U. CURV RATING

   —— —- ——– ——— ——— ——— ———

   –

   TOTAL SPECIFIED MVAR COMPENSATION

   : 0.00000 reduced 0.00000

   ———————————————————–

   –

   TOTAL (Including out of service units)

   TOTAL SPECIFIED MW GENERATION : 450.00000

   TOTAL MIN MVAR LIMIT OF GENERATOR

   : 140.00000

   TOTAL MAX MVAR LIMIT OF GENERATOR : 235.83100

   TOTAL SPECIFIED MW LOAD : 300.00000 reduced 300.00000

   TOTAL SPECIFIED MVAR LOAD : 170.00000 reduced 170.00000

   TOTAL SPECIFIED MVAR COMPENSATION

   : 0.00000 reduced 0.00000

   ———————————————————–

   –

   GENERATOR DATA FOR FREQUENCY DEPENDENT LOAD FLOW

   1 1 Bus1 250.0000 70.0000 165.8310

   1.0000 0 300.00 3

   2 2 Bus2 200.0000 70.0000 70.0000

   1.0000 0 250.00 3

   SLNO* FROM FROM P-RATE P-MIN P-MAX %DROOP PARTICI BIAS

   NODE NAME* MW MW MW FACTOR SETTING

   C0 C1

   ———————————————————– C2

   –

   LOAD DATA

   —— —- ——– ——– ——— ——— ——— –

   –

   SLNO FROM FROM REAL REACTIVE COMP COMPENSATING MVAR VALUE CHAR F/V

   * NODE NAME* MW MVAR MVAR MIN MAX STEP NO NO

   1 1 Bus1 250.000 0.0000 250.0000

   4.0000 0.0000 0.0000

   100.0000

   10.0000 0.0000

   2 2 Bus2 200.000 0.0000 200.0000

   4.0000 0.0000 0.0000

   STAT

   0.0000

   0.0000 0.0000

   —- —- ——– ——– ——– ——– ——- ——- 1 2 Bus2 250.000 150.000 0.000 0.000

   100.000 1.000 0 0

   ———————————————————–

   ——————–

   Slack bus angle (degrees) : 0.00

   ———————————————————–

   –

   TOTAL NUMBER OF ISLANDS IN THE GIVEN SYSTEM : 1

   TOTAL NUMBER OF ISLANDS HAVING ATLEAST ONE GENERATOR : 1

   SLACK BUSES CONSIDERED FOR THE STUDY

   ISLAND NO. SLACK BUS NAME SPECIFIED MW

   ———- ——— ——– ———— 1 1 Bus1 250.000

   ———————————————————–

   –

   ITERATION MAX P BUS MAX P MAX Q BUS MAX Q

   COUNT NUMBER PER UNIT NUMBER PER UNIT

   ——— ——— ——– ——— ——–

   ———————————————————–

   –

   LINE FLOWS AND LINE LOSSES

   SLNO CS FROM FROM TO TO FORWARD LOSS %

   NODE NAME NODE NAME MW MVAR MW MVAR LOADING

   – 1 1 1 Bus1 2 Bus2	39.327	24.288
   2 1 1 Bus1 3 Bus3	62.867	38.401
   3 1 2 Bus2 3 Bus3	-11.921	-32.935
   0.3574 -5.8880 15.2&

   —- — —- ——– —- ——– ——– ——– ——-

   1.2360 -22.8217 26.3^

   0.6014 -8.6200 32.6^

   ———————————————————–

   –

   ! NUMBER OF LINES LOADED BEYOND 125% : 0

   1	2	0.500	3	0.149	100% AND 125% : 0
   2	2	0.055	3	0.006	# NUMBER OF LINES LOADED BETWEEN
   3	2	0.004	3	0.000	75% AND 100% : 0
   4	2	0.000	3	0.000	$ NUMBER OF LINES LOADED BETWEEN
   5	2	0.000	2	0.822	50% AND 75% : 0
   6	2	0.170	3	0.029	^ NUMBER OF LINES LOADED BETWEEN
   7	2	0.019	3	0.003	25% AND 50% : 2
   8	2	0.001	2	0.000	& NUMBER OF LINES LOADED BETWEEN
   9	3	0.000	2	0.000	1% AND 25% : 1

   @ NUMBER OF LINES LOADED BETWEEN

   Number of p iterations : 6 and Number of q iterations : 7

   ———————————————————–

   –

   BUS VOLTAGES AND POWERS

   NODE FROM V-MAG ANGLE MW MVAR MW MVAR MVAR

   NO. NAME P.U. DEGREE GEN GEN LOAD LOAD COMP

   —- ——– —— —— ——– ——– ——– —-

   —- ——–

   102.194	62.689
   200.000	70.000
   0.000	0.000

   1 Bus1 1.0000 0.00

   0.000 0.000 0.000 <

   2 Bus2 0.9226 -2.93

   250.000 150.000 0.000 @

   3 Bus3 0.9585 -2.74

   50.000 20.000 0.000

   ———————————————————–

   –

   NUMBER OF BUSES EXCEEDING MINIMUM VOLTAGE LIMIT (@ mark) : 1 NUMBER OF BUSES EXCEEDING MAXIMUM VOLTAGE LIMIT (# mark) : 0 NUMBER OF GENERATORS EXCEEDING MINIMUM Q LIMIT (< mark) : 1

   NUMBER OF GENERATORS EXCEEDING MAXIMUM Q LIMIT (> mark) : 0

   * NUMBER OF LINES LOADED BETWEEN 0% AND 1% : 0

   ———————————————————–

   –

   ISLAND FREQUENCY SLACK-BUS CONVERGED(1)

   —— ——— ———– ———— 1 50.00000 1 0

   ———————————————————–

   –

   Summary of results

   TOTAL REAL POWER GENERATION :

   302.194 MW

   TOTAL REAL POWER INJECT,-ve L :

   0.000 MW

   TOTAL REACT. POWER GENERATION : 132.689 MVAR

   GENERATION pf : 0.916

   TOTAL SHUNT REACTOR INJECTION : –

   0.000 MW

   TOTAL SHUNT REACTOR INJECTION : –

   0.000 MVAR

   TOTAL SHUNT CAPACIT.INJECTION : –

   0.000 MW

   TOTAL SHUNT CAPACIT.INJECTION : –

   0.000 MVAR

   TOTAL TCSC REACTIVE DRAWL :

   0.000 MVAR

   TOTAL SPS REACTIVE DRAWL :

   0.000 MVAR

   TOTAL UPFC FACTS. INJECTION : – 0.0000 MVAR

   TOTAL SHUNT FACTS.INJECTION :

   0.000 MVAR

   TOTAL SHUNT FACTS.DRAWAL :

   0.000 MVAR

   TOTAL REAL POWER LOAD : 300.000 MW

   TOTAL REAL POWER DRAWAL -ve g :

   0.000 MW

   TOTAL REACTIVE POWER LOAD :

   170.000 MVAR

   LOAD pf : 0.870

   TOTAL COMPENSATION AT LOADS :

   0.000 MVAR

   TOTAL HVDC REACTIVE POWER :

   0.000 MVAR

   TOTAL REAL POWER LOSS (AC+DC) : 2.194845 MW ( 2.194845+ 0.000000) PERCENTAGE REAL LOSS (AC+DC) : 0.726

   TOTAL REACTIVE POWER LOSS : – 37.329685 MVAR

   ———————————————————–

   ——————–

   Zone wise distribution Description Zone # 1

   —————- ———-

   MW generation 302.1941

   MVAR generation 132.6894

   MW load 300.0000

   MVAR load 170.0000

   MVAR compensation 0.0000

   MW loss 2.1948

   MVAR loss -37.3297

   MVAR – inductive 0.0000

   MVAR – capacitive 0.0000

   ———————————————————–

   ——————–

   Zone wise export(+ve)/import(-ve) Zone # 1 MW & MVAR

   —— ——– ——– 1 —–

   Area wise distribution Description Area # 1

   —————- ———-

   MW generation 302.1941

   MVAR generation 132.6894

   MW load 300.0000

   MVAR load 170.0000

   MVAR compensation 0.0000

   MW loss 2.1948

   MVAR loss -37.3297

   MVAR – inductive 0.0000

   MVAR – capacitive 0.0000

   ——————————————————-

   ———————————————————–

   ——————–

   Date and Time : Fri Oct 17 12:23:30 2014

   ———————————————————–

   –

6. OUTPUT RESULT OF LOAD FLOW

   ANALYSIS

   Figure-3 Output Result of Load Flow Analysis

7. CONCLUSION

Power flow or load-flow studies are important for planning future expansion of power systems as well as in determining the best operation of existing systems. The principal information obtained from the power flow study is the magnitude and phase angle of the voltage at each bus, and the real and reactive power flowing in each line. In this paper, Gauss-Siedel method is used for analyzing the load flow of the IEEE-3 bus systems. This is verified by using the guass-seidel method and Mipower for 3 bus system. This Mipower software can be applicable for any number of buses. The standard IEEE 3 bus input data is used for IEEE 3 bus system .The future scope for this project can be extended with Newton-Raphson method and Fast Decoupled methods.

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