Power System Faults _fault in 3phase System_project-1

8/3/2019 Power System Faults _fault in 3phase System_project-1

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Presented by: INDRAJEET PRASAD

SHIVANANDA PUKHREM

JOAN JIMIENEZ ANGELES

2011-12

WROCLAW UNIVERSITY OF TECHNOLOGYWROCLAW UNIVERSITY OF TECHNOLOGYWROCLAW UNIVERSITY OF TECHNOLOGYWROCLAW UNIVERSITY OF TECHNOLOGYFACULTY OF ELECTRICAL ENGINEERING

[ POWER SYSTEM FAULTPOWER SYSTEM FAULTPOWER SYSTEM FAULTPOWER SYSTEM FAULT

PROJECT NOPROJECT NOPROJECT NOPROJECT NO----1111 ]

Prof. Dr. Hab. In Jan Iykowski


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2 Presented by: INDRAJEET PRASAD, SHIVANANDA PUKHREM, JOAN JIMIENEZ ANGELE

PROJECT NO-1POWER SYSTEM FAULT

INDEX:

2. Introduction 3

3. Variables used in the line code program. 4

4. Program code 5

5. Graphics results 10

5.1. Three phase voltage.. 105.2. Phase current and their magnitude. 11

5.3. Phase voltage and their magnitude 13

6. Consequences of the fault 14

7. Conclusion 15


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2. INTRODUCTION:

With this report we will try to familiarize with some code lines of Matlab. Thus in

the next pages will see how to get from a simulation of and electrical system

composed by one transmission line with 2 transformers for measuring (CT and VT)

We will see also how to work with some commands from Matlab that will be

useful to obtain some graphics which will help to get some information about

where and when has been the fault in the system.

There are two buses called (S)ending and (R)eciving. That has to be considered to

name the different variables.


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3. VARIABLES USED IN LINE CODE PROGRAM:

3.1 Information about the nomenclature of the simulation code.

Time interval: from tSTART=0 to tEND=12 ms

Fundamental frequency: f1=50 Hz

Sampling frequency: fs=1000 Hz.

n: 20. Number of number of samples in a single fundamental frequency period.

theta_i: 1500; CT ratio

theta_v: 3636.36; VT ratio

Current and voltages parameters:

iS_af: Side S phase 'a' current after filtration.

iS_bf: Side S phase 'b' current after filtration.

iS_cf: Side S phase 'c' current after filtration.

vS_af: Side S - phase 'a' voltage after filtration.

vS_bf: Side S - phase 'b' voltage after filtration.

vS_cf: Side S - phase 'c' voltage after filtration.

Notation used in the above specification of current and voltage signals: i-current;

v-voltage; S-sending end;


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4. PROGRAM CODE:

% cd d:\Student\PSFs_Pr1

% Pr1

clearall;

theta_i=1500; % CT ratio

theta_v=3636.36; % VT ratio

n=20; % number of samples in a single fundamental frequency period

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Standard full-cycle FOURIER FILTRATION:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

dT=2*pi/n;

fork=1:n,

alfa=dT/2+(k-1)*dT;

FF(k)=cos(alfa)+sqrt(-1)*sin(alfa);end;

FF=-2*FF/n;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

READING AND TRANSPOSING *.PL4 FILES.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

x=readpl452;

size(x),

y=x';

size(y),

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

CURRENT Signals after filtration (full-cycle FOURIER FILTRATION):

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


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iS_af(1,:)=theta_i*filter(FF,1,y(2

iS_bf(1,:)=theta_i*filter(FF,1,y(3,:));

iS_cf(1,:)=theta_i*filter(FF,1,y(4,:));

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

VOLTGAE Signals after filtration (full-cycle FOURIER FILTRATION):

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

vS_af(1,:)=theta_i*filter(FF,1,y(5,:));

vS_bf(1,:)=theta_i*filter(FF,1,y(6,:));

vS_cf(1,:)=theta_i*filter(FF,1,y(7,:));

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

PLOT FOR A SINGLE PHASES MAGNITUDE CURRENT:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure(2);

plot(y(1,:), theta_i*y(2,:), 'r-');

holdon;

gridon;

plot(y(1,:), abs(iS_af(1,:)), 'r-', y(1,:), abs(iS_af(1,:)), 'ro');

title('Phase current and its magnitude');

xlabel('Time [s]'); ylabel('Current and Magnitude [A B C]');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

PLOT FOR B SINGLE PHASES MAGNITUDE CURRENT:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure(2);

plot(y(1,:), theta_i*y(3,:), 'g-');

holdon;

gridon;

plot(y(1,:), abs(iS_bf(1,:)), 'g-', y(1,:), abs(iS_bf(1,:)), 'gx');


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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

PLOT FOR C SINGLE PHASES MAGNITUDE CURRENT:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure(2);

plot(y(1,:), theta_i*y(4,:), 'b-');

holdon;gridon;

plot(y(1,:), abs(iS_cf(1,:)), 'b-', y(1,:), abs(iS_cf(1,:)), 'bx');



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%PLOT FOR ALL THE VOLTAGES PHASES:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

v_a=theta_v*y(5,:); % Phase 'a' voltage.

v_b=theta_v*y(6,:); % Phase 'b' voltage.

v_c=theta_v*y(7,:); % Phase 'c' voltage.

figure(1);

plot(y(1,:), v_a, 'r-', y(1,:), theta_v*y(6,:), 'g-', y(1,:), theta_v*y(7,:), 'b-');

plot(y(1,:), v_a, 'r-', y(1,:), v_b, 'g-', y(1,:), v_c, 'b-');


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grid;

title('Three-phase voltages');xlabel('Time [s]'); ylabel('Voltage [V]'); Legend('v_a','v_b','v_c');

% axis([0, 0.02, -500, 500]);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

PLOT THE A SINGLE PHASE MAGNITUDE VOLTAGE:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure(3);

plot(y(1,:), theta_i*y(5,:), 'r-');

holdon;

gridon;

plot(y(1,:), abs(vS_af(1,:)), 'rx', y(1,:), abs(vS_af(1,:)), 'rx');

title('Phases Voltage and Magnitude ');

xlabel('Time [s]'); ylabel('Voltage and Magnitude [A B C]');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

PLOT THE B SINGLE PHASE MAGNITUDE VOLTAGE:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure(3);

plot(y(1,:), theta_i*y(6,:), 'g-');

holdon;

gridon;

plot(y(1,:), abs(vS_bf(1,:)), 'go', y(1,:), abs(vS_bf(1,:)), 'go');


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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

PLOT THE C SINGLE PHASE MAGNITUDE VOLTAGE:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure(3);

plot(y(1,:), theta_i*y(7,:), 'b-');

holdon;gridon;

plot(y(1,:), abs(vS_cf(1,:)), 'bo', y(1,:), abs(vS_cf(1,:)), 'bo');



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

END%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


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5. GRAPHICS RESULTS:

According to the kind of the time interval we can distinguished two main parts in

the graphics:

PRE-FAULT INTERVAL: From t-0 to t-6ms. There isn't any disturbance in the

amplitude of the voltages of the phases.

FAULT INTERVAL: From t-6ms to t-12ms. Here disturbance is occurred due tothe fault in the system.

The different graphics obtained from the program are showed down:

Fig 1: three phase voltage.

Fig 2: phase current and magnitude.Fig 3: phase voltage and magnitude.

Now we can star talk about the different results that are showed in the different

graphics.

5.1 Three phase voltage.

In this figure; we can see the three phase voltage. And as because of the fault theamplitude of the phase A and B decreases and phase C increases its original

amplitude.

Since due to fault in the system one of the phase is carrying more load so that the

reason its increasing its amplitude and the other two phases decreases its original

amplitude after fault.


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FIG:1 THREE PHASE VOLTAGE

5.2 Phase currents and their magnitude.

In this figure it represents the phase current and its magnitude of the system.

We know that,

P=V*I

As we saw before in figure 1, due to the fault in the system the voltage increased,

so if the power has to be maintain constant, the only parameter that has to

change is the current, because of that the current has suffered and increases of its

value and magnitude.


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FIG.2 : PHASE CURRENT AND ITS MAGNITUDE

5.3 Phases Voltage and their magnitude:

In figure 3, it depicts the magnitude of the phases A,B and C. As we can see in

figure due to the fault in the system, phases A and B magnitude reduces while themagnitude of phase C increases


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FIG.3 : THREE PHASE VOLATAGE AND MAGNITUDE


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6.CONSEQUENCES OF FAULTS:

Fire is a serious result of major un-cleared faults, may destroy the equipment of its

origin, but also may spread in the system causing total failure.

The short circuit (the most common type of fault) may have any of the following

consequences:

A great reduction of the line voltage over a major part of the power system,leading to the breakdown of the electrical supply to the consumer and may

produce wastage in production.

An electrical arc often accompanying a short circuit may damage the other

apparatus in the system.

Damage to the other apparatus in the system due to overheating and

mechanical forces.

Disturbances to the stability of the electrical system and this may even lead to a

complete blackout of a given power system.

Considerable reduction of voltage on healthy feeders connected to the system

having fault, which can cause abnormal currents drawn by motors or the motors

will be stopped (causing loss of industrial production) and then will have to be

restarted.


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7.CONCLUSION:

A fault in an electric power system is studied in this project through MATLAB

programming.

Any abnormal flow of electric current in an electric power system is considered as

a fault.In this particular project the fault is occurred between two phases A and B i.e, Red

and Green.

The fault can be between phase to phase, phase to ground or phase to phase to

ground. Through this project we have learn that due to any kind of fault in three

phase system there is a transient sudden surge increase of current in the power

system affecting the other healthy lines.

Many faults in overhead power lines are transient in nature.

At the occurrence of a fault power system protection operates to isolate area of

the fault.A transient fault will then clear and the power line can resume to service.

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Power System Faults _fault in 3phase System_project-1

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