EE2404 POWER SYSTEM SIMULATION LABORATORY

AIM

To acquire software development skills and experience in the usage of standard

packages necessary for analysis and simulation of power system required for its

planning, operation and control.

OBJECTIVES

i. To develop simple C programs for the following basic requirements:

a) Formation of bus admittance and impedance matrices and network

solution.

b) Power flow solution of small systems using simple method, Gauss-

Seidel P.F. method.

c) Unit Commitment and Economic Dispatch.

ii. To acquire experience in the usage of standard packages for the

following analysis / simulation / control functions.

a) Steady-state analysis of large system using NRPF and FDPF methods.

b) Quasi steady-state (Fault) analysis for balanced and unbalanced faults.

c) Transient stability simulation of multimachine power system.

d) Simulation of Load-Frequency Dynamics and control of power system.

1. Computation of Parameters and Modelling of Transmission Lines

2. Formation of Bus Admittance and Impedance Matrices and Solution of

Networks.

3. Load Flow Analysis - I : Solution of Load Flow And Related Problems Using

Gauss-Seidel Method

4. Load Flow Analysis - II: Solution of Load Flow and Related Problems

Using Newton-Raphson and Fast-Decoupled Methods

5. Fault Analysis

6. Transient and Small Signal Stability Analysis: Single-Machine Infinite Bus

System

7. Transient Stability Analysis of Multimachine Power Systems

8. Electromagnetic Transients in Power Systems

9. Load – Frequency Dynamics of Single- Area and Two-Area Power Systems

10. Economic Dispatch in Power Systems.

TOTAL : 45 PERIODS

Detailed Syllabus

1. COMPUTATION OF PARAMETERS AND MODELLING OF TRANSMISSION

LINES

Aim

(i) To determine the positive sequence line parameters L and C per phase per

kilometer of a three phase single and double circuit transmission lines for

different conductor arrangements.

(ii) To understand modelling and performance of short, medium and long lines.

Exercises

1.1 Computation of series inductance and shunt capacitance per phase per km of a

three phase line with flat horizontal spacing for single stranded and bundle

conductor configuration.

1.2 Computation of series inductance and shunt capacitance per phase per km of a

three phase double circuit transmission line with vertical conductor arrangement

with bundle conductor.

1.3 Computation of voltage, current, power factor, regulation and efficiency at the

receiving end of a three phase Transmission line when the voltage and power at

the sending end are given. Use П model.

1.4 Computation of receiving end voltage of a long transmission for a given sending

end voltage and when the line is open circuited at receiving. Also compute the

shunt reactor compensation to limit the no load receiving end voltage to specified

value.

1.5 Determination of the voltage profile along the long transmission line for the

following cases of loading at receiving end (i) no load (ii) rated load (iii) surge

impedance loading and (iv) receiving end short circuited.

2. FORMATION OF BUS ADMITTANCE AND IMPEDANCE MATRICES AND

SOLUTION OF NETWORKS

Aim

To understand the formation of network matrices, the bus admittance matrix Y and the

bus impedance matrix Z of a power network, to effect certain required changes on these

matrices and to obtain network solution using these matrices.

Exercises

2.1 Write a program in C language for formation of bus admittance matrix Y of a power

network using the “Two-Rule Method”, given the data pertaining to the transmission

lines, transformers and shunt elements. Run the program for a sample 6 bus

system and compare the results with that obtained using a standard software.

2.2 Modify the program developed in 2.1 for the following:

(i) To obtain modified Y matrix for the outage of a transmission line, a

Transformer and a shunt element.

(ii) To obtain network solution V given the current injection vector I

(iii) To obtain full Z matrix or certain specified columns of Z matrix.

Verify the correctness of the modified program using 6 bus sample system

* 2.3 Write a program in C language for forming bus impedance matrix Z using

the “Building Algorithm”.

* Optional (not mandatory)

EXPERIMENT 3

LOAD FLOW ANALYSIS - I : SOLUTION OF LOAD FLOW AND RELATED

PROBLEMS USING GAUSS-SEIDEL METHOD

Aim

(i) To understand, the basic aspects of steady state analysis of power systems

that are required for effective planning and operation of power systems.

(ii) To understand, in particular, the mathematical formulation of load flow model

in complex form and a simple method of solving load flow problems of small

sized system using Gauss-Seidel iterative algorithm

Exercises

3.1 Write a program in c language for iteratively solving load flow equations using

Gauss-Seidel method with provision for acceleration factor and for dealing

with P-V buses. Run the program for a sample 6 bus system (Base case)

and compare the results with that obtained using a standard software.

3.2 Solve the “Base case” in 3.1 for different values of acceleration factor, draw the

convergence characteristics “Iteration taken for convergence versus acceleration

factor” and determine the best acceleration factor for the system under study.

3.3 Solve the “Base Case” in 3.1 for the following changed conditions and comment on

the results obtained, namely voltage magnitude of the load buses and transmission

losses:

(i) Dropping all shunt capacitors connected to network

(ii) Changing the voltage setting of generators Vgi over the range 1.00 to 1.05

(iii) Changing the tap setting of the transformers, ai, over the range 0.85 to 1.1

3.4 Resolve the base case in 3.1 after shifting generation from one generator bus to

another generator bus and comment on the MW loading of lines and transformers.

4. LOAD FLOW ANALYSIS – I: SOLUTION OF LOAD FLOW AND RELATED

PROBLEMS USING NEWTON-RAPHSON AND FAST DECOUPLED

METHODS

Aim

(i) To understand the following for medium and large scale power systems:

(a) Mathematical formulation of the load flow problem in real variable form

(b) Newton-Raphson method of load flow (NRLF) solution

(c) Fast Decoupled method of load flow (FDLF) solution

(ii) To become proficient in the usage of software for practical problem solving in

the areas of power system planning and operation.

(iii) To become proficient in the usage of the software in solving problems using

Newton-Raphson and Fast Decoupled load flow methods.

Exercises

4.1 Solve the load flow problem (Base case) of a sample 6 bus system using Gauss-

Seidel, Fast Decoupled and Newton-Raphson Load Flow programs for a mismatch

convergence tolerance of 0.01 MW, plot the convergence characteristics and

compare the convergence rate of the three methods.

4.2 Obtain an optimal (minimum transmission loss) load flow solution for the Base case

loading of 6 bus sample system by trial and error approach through repeated load

flow solutions using Fast Decoupled Load Flow package for different combinations

of generator voltage settings, transformer tap settings, and reactive power of shunt

elements.

4.3 Carry out contingency analysis on the optimal state obtained in 4.2 for outage of a

transmission line using FDLF or NRLF package.

4.4 Obtain load flow solutions using FDLF or NRLF package on the optimal state

obtained in 4.2 but with reduced power factor (increased Q load) load and comment

on the system voltage profile and transmission loss.

4.5 Determine the maximum loadability of a 2 bus system using analytical solution as

well as numerical solution using FDLF package. Draw the P-V curve of the system.

4.6 For the base case operating state of the 6 bus system in 4.1 draw the P-V curve for

the weakest load bus. Also obtain the voltage Stability Margin (MW Index) at

different operating states of the system.

4.7 For the optimal operating state of 6 bus system obtained in 4.2 determine the

Available Transfer Capability (ATC) between a given “source bus” and a given “s

5. FAULT ANALYSIS

Aim

To become familiar with modelling and analysis of power systems under faulted

condition and to compute the fault level, post-fault voltages and currents for different

types of faults, both symmetric and unsymmetric.

Exercises

5.1 Calculate the fault current, post fault voltage and fault current through the branches

for a three phase to ground fault in a small power system and also study the effect of

neighbouring system. Check the results using available software.

5.2 Obtain the fault current, fault MVA, Post-fault bus voltages and fault current

distribution for single line to ground fault, line-to-line fault and double line to ground

fault for a small power system, using the available software. Also check the fault

current and fault MVA by hand calculation.

5.3 Carryout fault analysis for a sample power system for LLLG, LG, LL and LLG faults

and prepare the report.

6. TRANSIENT AND SMALL-SIGNAL STABILITY ANALYSIS: SINGLE

MACHINE-INFINITE BUS SYSTEM

Aim

To become familiar with various aspects of the transient and small signal stability

analysis of Single-Machine Infinite Bus (SMIB) system.

Exercises

For a typical power system comprising a generating, step-up transformer, double-circuit

transmission line connected to infinite bus:

Transient Stability Analysis

6.1 Hand calculation of the initial conditions necessary for the classical model of the

synchronous machine.

6.2 Hand computation of critical clearing angle and time for the fault using equal area

criterion.

6.3 Simulation of typical disturbance sequence: fault application, fault clearance by

opening of one circuit using the software available and checking stability by plotting

the swing curve.

6.4 Determination of critical clearing angle and time for the above fault sequence

through trial and error method using the software and checking with the hand

computed value.

6.5 Repetition of the above for different fault locations and assessing the fault severity

with respect to the location of fault

6.6 Determination of the steady-state and transient stability margins.

Small-signal Stability Analysis:

6.7 Familiarity with linearised swing equation and characteristic equation and its roots,

damped frequency of oscillation in Hz, damping ratio and undamped natural

frequency.

6.8 Force-free time response for an initial condition using the available software.

6.9 Effect of positive, negative and zero damping.

7. TRANSIENT STABILITY ANALYSIS OF MULTIMACHINE POWER SYSTEMS

Aim

To become familiar with modelling aspects of synchronous machines and network, stateof-

the-art algorithm for simplified transient stability simulation, system behaviour when

subjected to large disturbances in the presence of synchronous machine controllers and

to become proficient in the usage of the software to tackle real life problems encountered

in the areas of power system planning and operation.

Exercises

For typical multi-machine power system:

7.1 Simulation of typical disturbance sequence: fault application, fault clearance by

opening of a line using the software available and assessing stability with and

without controllers.

7.2 Determination of critical clearing angle and time for the above fault sequence

through trial and error method using the software.

7.3 Determination of transient stability margins.

7.4 Simulation of full load rejection with and without governor.

7.5 Simulation of loss of generation with and without governor.

7.6 Simulation of loss of excitation (optional).

7.7 Simulation of under frequency load shedding scheme (optional).

8. ELECTROMAGNETIC TRANSIENTS IN POWER SYSTEMS

Aim

To study and understand the electromagnetic transient phenomena in power systems

caused due to switching and faults by using Electromagnetic Transients Program

(EMTP) and to become proficient in the usage of EMTP to address problems in the

areas of over voltage protection and mitigation and insulation coordination of EHV

systems.

Exercises

Using the EMTP software or equivalent

Simulation of single-phase energisation of the load through single-phase pi-model of a

transmission line and understanding the effect of source inductance.

8.1 Simulation of three-phase energisation of the load through three-phase pi-model

of a transmission line and understanding the effect of pole discrepancy of a

circuit breaker.

8.2 Simulation of energisation of an open-ended single-phase distributed parameter

transmission line and understanding the travelling wave effects.

8.3 Simulation of a three-phase load energisation through a three-phase distributed

parameter line with simultaneous and asynchronous closing of circuit breaker

and studying the effects.

8.4 Study of transients due to single line-to-ground fault.

8.5 Computation of transient recovery voltage.

9. LOAD-FREQUENCY DYNAMICS OF SINGLE-AREA AND TWOAREA

POWER SYSTEMS

Aim

To become familiar with the modelling and analysis of load-frequency and tie-line flow

dynamics of a power system with load-frequency controller (LFC) under different control

modes and to design improved controllers to obtain the best system response.

Exercises

9.1 Given the data for a Single-Area power system, simulate the load-frequency

dynamics (only governor control) of this area for a step load disturbance of small

magnitude, plot the time response of frequency deviation and the corresponding

change in turbine power. Check the value of steady state frequency deviation

obtained from simulation with that obtained by hand calculation.

9.2 Carry out the simulation of load-frequency dynamics of the Single-Area power

system in 9.1 with Load-frequency controller (Integral controller) for different values

of KI (gain of the controller) and choose the best value of KI to give an “optimal”

response with regard to peak over shoot, settling time, steady-state error and Mean-

Sum-Squared-Error.

9.3 Given the data for a two-area (identical areas) power system, simulate the loadfrequency

dynamics (only governor control) of this system for a step load

disturbance in one area and plot time response of frequency deviation, turbine

power deviation and tie-line power deviation. Compare the steady-state frequency

deviation obtained with that obtained in the case of single-area system.

9.4 Carry out the simulation of load-frequency dynamics of two-area system in 9.3 for

the following control modes:

(i) Flat tie-line control

(ii) Flat frequency control

(iii) Frequency bias tie-line control

and for the frequency bias Tie-line control mode, determine the optimal values of

gain and frequency bias factor required to get the “best” time response.

9.5 Given the data for a two-area (unequal areas) power system, determine the best

controller parameters; gains and bias factors to give an optimal response for

frequency deviation and tie-line deviations with regard to peak overshoot, settling

time, steady-state error and Mean-Sum-Squared-Error.

10. ECONOMIC DISPATCH IN POWER SYSTEMS

Aim

(i) To understand the basics of the problem of Economic Dispatch (ED) of optimally

adjusting the generation schedules of thermal generating units to meet the system

load which are required for unit commitment and economic operation of power

systems.

(ii) To understand the development of coordination equations (the mathematical model

for ED) without and with losses and operating constraints and solution of these

equations using direct and iterative methods

Exercises

10.1. Write a program in ‘C’ language to solve economic dispatch problem of a

power system with only thermal units. Take production cost function as

quadratic and neglect transmission loss.

10.2. Write a program in ‘C’ language to solve economic dispatch problem of a

power system. Take production cost as quadratic and include transmission

loss using loss co-efficient. Use λ-iteration algorithm for solving the coordination

equations.

10.3. Determine using the program developed in exercise 10.1 the economic

generation schedule of each unit and incremental cost of received power for a

sample power system, for a given load cycle.

10.4. Determine using the program developed in exercise 10.2 the economic

generation schedule of each unit, incremental cost of received power and

transmission loss for a sample system, for the given load levels.

10.5. Apply the software module developed in 10.1 to obtain an optimum unit

commitment schedule for a few load levels.

REQUIREMENT FOR A BATCH OF 30 STUDENTS

S.No. Description of Equipment Quantity

required

1. Personal computers (Pentium-IV, 80GB, 512

MBRAM)

25

2. Printer laser 1

3. Dotmatrix 1

4. Server (Pentium IV, 80GB, 1GBRAM) (High

Speed Processor)

1

5. Software: E.M.T.P/ETAP/CYME/MIPOWER

/any power system simulation software

5 licenses

6. Compliers: C, C++, VB, VC++ 25 users

AIM

To acquire software development skills and experience in the usage of standard

packages necessary for analysis and simulation of power system required for its

planning, operation and control.

OBJECTIVES

i. To develop simple C programs for the following basic requirements:

a) Formation of bus admittance and impedance matrices and network

solution.

b) Power flow solution of small systems using simple method, Gauss-

Seidel P.F. method.

c) Unit Commitment and Economic Dispatch.

ii. To acquire experience in the usage of standard packages for the

following analysis / simulation / control functions.

a) Steady-state analysis of large system using NRPF and FDPF methods.

b) Quasi steady-state (Fault) analysis for balanced and unbalanced faults.

c) Transient stability simulation of multimachine power system.

d) Simulation of Load-Frequency Dynamics and control of power system.

1. Computation of Parameters and Modelling of Transmission Lines

2. Formation of Bus Admittance and Impedance Matrices and Solution of

Networks.

3. Load Flow Analysis - I : Solution of Load Flow And Related Problems Using

Gauss-Seidel Method

4. Load Flow Analysis - II: Solution of Load Flow and Related Problems

Using Newton-Raphson and Fast-Decoupled Methods

5. Fault Analysis

6. Transient and Small Signal Stability Analysis: Single-Machine Infinite Bus

System

7. Transient Stability Analysis of Multimachine Power Systems

8. Electromagnetic Transients in Power Systems

9. Load – Frequency Dynamics of Single- Area and Two-Area Power Systems

10. Economic Dispatch in Power Systems.

TOTAL : 45 PERIODS

Detailed Syllabus

1. COMPUTATION OF PARAMETERS AND MODELLING OF TRANSMISSION

LINES

Aim

(i) To determine the positive sequence line parameters L and C per phase per

kilometer of a three phase single and double circuit transmission lines for

different conductor arrangements.

(ii) To understand modelling and performance of short, medium and long lines.

Exercises

1.1 Computation of series inductance and shunt capacitance per phase per km of a

three phase line with flat horizontal spacing for single stranded and bundle

conductor configuration.

1.2 Computation of series inductance and shunt capacitance per phase per km of a

three phase double circuit transmission line with vertical conductor arrangement

with bundle conductor.

1.3 Computation of voltage, current, power factor, regulation and efficiency at the

receiving end of a three phase Transmission line when the voltage and power at

the sending end are given. Use П model.

1.4 Computation of receiving end voltage of a long transmission for a given sending

end voltage and when the line is open circuited at receiving. Also compute the

shunt reactor compensation to limit the no load receiving end voltage to specified

value.

1.5 Determination of the voltage profile along the long transmission line for the

following cases of loading at receiving end (i) no load (ii) rated load (iii) surge

impedance loading and (iv) receiving end short circuited.

2. FORMATION OF BUS ADMITTANCE AND IMPEDANCE MATRICES AND

SOLUTION OF NETWORKS

Aim

To understand the formation of network matrices, the bus admittance matrix Y and the

bus impedance matrix Z of a power network, to effect certain required changes on these

matrices and to obtain network solution using these matrices.

Exercises

2.1 Write a program in C language for formation of bus admittance matrix Y of a power

network using the “Two-Rule Method”, given the data pertaining to the transmission

lines, transformers and shunt elements. Run the program for a sample 6 bus

system and compare the results with that obtained using a standard software.

2.2 Modify the program developed in 2.1 for the following:

(i) To obtain modified Y matrix for the outage of a transmission line, a

Transformer and a shunt element.

(ii) To obtain network solution V given the current injection vector I

(iii) To obtain full Z matrix or certain specified columns of Z matrix.

Verify the correctness of the modified program using 6 bus sample system

* 2.3 Write a program in C language for forming bus impedance matrix Z using

the “Building Algorithm”.

* Optional (not mandatory)

EXPERIMENT 3

LOAD FLOW ANALYSIS - I : SOLUTION OF LOAD FLOW AND RELATED

PROBLEMS USING GAUSS-SEIDEL METHOD

Aim

(i) To understand, the basic aspects of steady state analysis of power systems

that are required for effective planning and operation of power systems.

(ii) To understand, in particular, the mathematical formulation of load flow model

in complex form and a simple method of solving load flow problems of small

sized system using Gauss-Seidel iterative algorithm

Exercises

3.1 Write a program in c language for iteratively solving load flow equations using

Gauss-Seidel method with provision for acceleration factor and for dealing

with P-V buses. Run the program for a sample 6 bus system (Base case)

and compare the results with that obtained using a standard software.

3.2 Solve the “Base case” in 3.1 for different values of acceleration factor, draw the

convergence characteristics “Iteration taken for convergence versus acceleration

factor” and determine the best acceleration factor for the system under study.

3.3 Solve the “Base Case” in 3.1 for the following changed conditions and comment on

the results obtained, namely voltage magnitude of the load buses and transmission

losses:

(i) Dropping all shunt capacitors connected to network

(ii) Changing the voltage setting of generators Vgi over the range 1.00 to 1.05

(iii) Changing the tap setting of the transformers, ai, over the range 0.85 to 1.1

3.4 Resolve the base case in 3.1 after shifting generation from one generator bus to

another generator bus and comment on the MW loading of lines and transformers.

4. LOAD FLOW ANALYSIS – I: SOLUTION OF LOAD FLOW AND RELATED

PROBLEMS USING NEWTON-RAPHSON AND FAST DECOUPLED

METHODS

Aim

(i) To understand the following for medium and large scale power systems:

(a) Mathematical formulation of the load flow problem in real variable form

(b) Newton-Raphson method of load flow (NRLF) solution

(c) Fast Decoupled method of load flow (FDLF) solution

(ii) To become proficient in the usage of software for practical problem solving in

the areas of power system planning and operation.

(iii) To become proficient in the usage of the software in solving problems using

Newton-Raphson and Fast Decoupled load flow methods.

Exercises

4.1 Solve the load flow problem (Base case) of a sample 6 bus system using Gauss-

Seidel, Fast Decoupled and Newton-Raphson Load Flow programs for a mismatch

convergence tolerance of 0.01 MW, plot the convergence characteristics and

compare the convergence rate of the three methods.

4.2 Obtain an optimal (minimum transmission loss) load flow solution for the Base case

loading of 6 bus sample system by trial and error approach through repeated load

flow solutions using Fast Decoupled Load Flow package for different combinations

of generator voltage settings, transformer tap settings, and reactive power of shunt

elements.

4.3 Carry out contingency analysis on the optimal state obtained in 4.2 for outage of a

transmission line using FDLF or NRLF package.

4.4 Obtain load flow solutions using FDLF or NRLF package on the optimal state

obtained in 4.2 but with reduced power factor (increased Q load) load and comment

on the system voltage profile and transmission loss.

4.5 Determine the maximum loadability of a 2 bus system using analytical solution as

well as numerical solution using FDLF package. Draw the P-V curve of the system.

4.6 For the base case operating state of the 6 bus system in 4.1 draw the P-V curve for

the weakest load bus. Also obtain the voltage Stability Margin (MW Index) at

different operating states of the system.

4.7 For the optimal operating state of 6 bus system obtained in 4.2 determine the

Available Transfer Capability (ATC) between a given “source bus” and a given “s

5. FAULT ANALYSIS

Aim

To become familiar with modelling and analysis of power systems under faulted

condition and to compute the fault level, post-fault voltages and currents for different

types of faults, both symmetric and unsymmetric.

Exercises

5.1 Calculate the fault current, post fault voltage and fault current through the branches

for a three phase to ground fault in a small power system and also study the effect of

neighbouring system. Check the results using available software.

5.2 Obtain the fault current, fault MVA, Post-fault bus voltages and fault current

distribution for single line to ground fault, line-to-line fault and double line to ground

fault for a small power system, using the available software. Also check the fault

current and fault MVA by hand calculation.

5.3 Carryout fault analysis for a sample power system for LLLG, LG, LL and LLG faults

and prepare the report.

6. TRANSIENT AND SMALL-SIGNAL STABILITY ANALYSIS: SINGLE

MACHINE-INFINITE BUS SYSTEM

Aim

To become familiar with various aspects of the transient and small signal stability

analysis of Single-Machine Infinite Bus (SMIB) system.

Exercises

For a typical power system comprising a generating, step-up transformer, double-circuit

transmission line connected to infinite bus:

Transient Stability Analysis

6.1 Hand calculation of the initial conditions necessary for the classical model of the

synchronous machine.

6.2 Hand computation of critical clearing angle and time for the fault using equal area

criterion.

6.3 Simulation of typical disturbance sequence: fault application, fault clearance by

opening of one circuit using the software available and checking stability by plotting

the swing curve.

6.4 Determination of critical clearing angle and time for the above fault sequence

through trial and error method using the software and checking with the hand

computed value.

6.5 Repetition of the above for different fault locations and assessing the fault severity

with respect to the location of fault

6.6 Determination of the steady-state and transient stability margins.

Small-signal Stability Analysis:

6.7 Familiarity with linearised swing equation and characteristic equation and its roots,

damped frequency of oscillation in Hz, damping ratio and undamped natural

frequency.

6.8 Force-free time response for an initial condition using the available software.

6.9 Effect of positive, negative and zero damping.

7. TRANSIENT STABILITY ANALYSIS OF MULTIMACHINE POWER SYSTEMS

Aim

To become familiar with modelling aspects of synchronous machines and network, stateof-

the-art algorithm for simplified transient stability simulation, system behaviour when

subjected to large disturbances in the presence of synchronous machine controllers and

to become proficient in the usage of the software to tackle real life problems encountered

in the areas of power system planning and operation.

Exercises

For typical multi-machine power system:

7.1 Simulation of typical disturbance sequence: fault application, fault clearance by

opening of a line using the software available and assessing stability with and

without controllers.

7.2 Determination of critical clearing angle and time for the above fault sequence

through trial and error method using the software.

7.3 Determination of transient stability margins.

7.4 Simulation of full load rejection with and without governor.

7.5 Simulation of loss of generation with and without governor.

7.6 Simulation of loss of excitation (optional).

7.7 Simulation of under frequency load shedding scheme (optional).

8. ELECTROMAGNETIC TRANSIENTS IN POWER SYSTEMS

Aim

To study and understand the electromagnetic transient phenomena in power systems

caused due to switching and faults by using Electromagnetic Transients Program

(EMTP) and to become proficient in the usage of EMTP to address problems in the

areas of over voltage protection and mitigation and insulation coordination of EHV

systems.

Exercises

Using the EMTP software or equivalent

Simulation of single-phase energisation of the load through single-phase pi-model of a

transmission line and understanding the effect of source inductance.

8.1 Simulation of three-phase energisation of the load through three-phase pi-model

of a transmission line and understanding the effect of pole discrepancy of a

circuit breaker.

8.2 Simulation of energisation of an open-ended single-phase distributed parameter

transmission line and understanding the travelling wave effects.

8.3 Simulation of a three-phase load energisation through a three-phase distributed

parameter line with simultaneous and asynchronous closing of circuit breaker

and studying the effects.

8.4 Study of transients due to single line-to-ground fault.

8.5 Computation of transient recovery voltage.

9. LOAD-FREQUENCY DYNAMICS OF SINGLE-AREA AND TWOAREA

POWER SYSTEMS

Aim

To become familiar with the modelling and analysis of load-frequency and tie-line flow

dynamics of a power system with load-frequency controller (LFC) under different control

modes and to design improved controllers to obtain the best system response.

Exercises

9.1 Given the data for a Single-Area power system, simulate the load-frequency

dynamics (only governor control) of this area for a step load disturbance of small

magnitude, plot the time response of frequency deviation and the corresponding

change in turbine power. Check the value of steady state frequency deviation

obtained from simulation with that obtained by hand calculation.

9.2 Carry out the simulation of load-frequency dynamics of the Single-Area power

system in 9.1 with Load-frequency controller (Integral controller) for different values

of KI (gain of the controller) and choose the best value of KI to give an “optimal”

response with regard to peak over shoot, settling time, steady-state error and Mean-

Sum-Squared-Error.

9.3 Given the data for a two-area (identical areas) power system, simulate the loadfrequency

dynamics (only governor control) of this system for a step load

disturbance in one area and plot time response of frequency deviation, turbine

power deviation and tie-line power deviation. Compare the steady-state frequency

deviation obtained with that obtained in the case of single-area system.

9.4 Carry out the simulation of load-frequency dynamics of two-area system in 9.3 for

the following control modes:

(i) Flat tie-line control

(ii) Flat frequency control

(iii) Frequency bias tie-line control

and for the frequency bias Tie-line control mode, determine the optimal values of

gain and frequency bias factor required to get the “best” time response.

9.5 Given the data for a two-area (unequal areas) power system, determine the best

controller parameters; gains and bias factors to give an optimal response for

frequency deviation and tie-line deviations with regard to peak overshoot, settling

time, steady-state error and Mean-Sum-Squared-Error.

10. ECONOMIC DISPATCH IN POWER SYSTEMS

Aim

(i) To understand the basics of the problem of Economic Dispatch (ED) of optimally

adjusting the generation schedules of thermal generating units to meet the system

load which are required for unit commitment and economic operation of power

systems.

(ii) To understand the development of coordination equations (the mathematical model

for ED) without and with losses and operating constraints and solution of these

equations using direct and iterative methods

Exercises

10.1. Write a program in ‘C’ language to solve economic dispatch problem of a

power system with only thermal units. Take production cost function as

quadratic and neglect transmission loss.

10.2. Write a program in ‘C’ language to solve economic dispatch problem of a

power system. Take production cost as quadratic and include transmission

loss using loss co-efficient. Use λ-iteration algorithm for solving the coordination

equations.

10.3. Determine using the program developed in exercise 10.1 the economic

generation schedule of each unit and incremental cost of received power for a

sample power system, for a given load cycle.

10.4. Determine using the program developed in exercise 10.2 the economic

generation schedule of each unit, incremental cost of received power and

transmission loss for a sample system, for the given load levels.

10.5. Apply the software module developed in 10.1 to obtain an optimum unit

commitment schedule for a few load levels.

REQUIREMENT FOR A BATCH OF 30 STUDENTS

S.No. Description of Equipment Quantity

required

1. Personal computers (Pentium-IV, 80GB, 512

MBRAM)

25

2. Printer laser 1

3. Dotmatrix 1

4. Server (Pentium IV, 80GB, 1GBRAM) (High

Speed Processor)

1

5. Software: E.M.T.P/ETAP/CYME/MIPOWER

/any power system simulation software

5 licenses

6. Compliers: C, C++, VB, VC++ 25 users

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