POWER SYSTEM FAULTS Fault Direction Discrimination PROJECT-2

Presented by: INDRAJEET PRASAD

SHIVANANDA PUKHREM JOAN JIMIENEZ ANGELES

2011-‘12 WROCLAW UNIVERSITY OF TECHNOLOGY

FACULTY OF ELECTRICAL ENGINEERING

[POWER SYSTEM FAULT

PROJECT NO-2 (FAULT DIRECTION DISCRIMINATION).] Prof. Dr. Hab. Inż Jan Iżykowski

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

PROJECT NO-2 POWER SYSTEM FAULT

INDEX: 1. Introduction…………………………………………………………………………………………….. 3 2. Variables used in the line code program………………………………………………….. 4 3. Program code…………………………………………………………………………………………. 5 4. Graphics results……………………………………………………………………………………….. 7

Fig 1: Task IIIA. Incremental positive resistance..................................... 7 Fig 2: Task IIIA. Incremental positive reactance and resistance.............. 8 Fig 3: Task IIIB. Incremental positive resistance...................................... 9 Fig 4: Task IIIB. Incremental positive reactance and resistance.............. 10 Fig 5: Task IIIB. Zoomed Incremental positive reactance &resistance.... 11

5. Conclusion………………………………………………………………………………………………… 12



1. INTRODUCTION: With this report we will try to familiarize with some code lines of Matlab Program. Since we detected the fault in the system in the 1st project. so in this Project our task is to find the direction of the fault by understanding the position of the impedance from incremental positive reactance and resistance graphs with respect to time axis. Here, In order to obtain the exact direction of the fault we define an A operator which is a complex no. with unit magnitude and 120 phase angle that is the operator which operates by 120 deg. anti clock wise direction. During fault, With the help of this A operator the unsymmetrical current and voltage components can be made symmetrical components . Therefore, We define positive sequence component of sending end current and voltage through A operator.



2. VARIABLES USED IN LINE CODE PROGRAM: 3.1 Information about the nomenclature of the simulation code. Time interval: from tSTART=0 to tEND=119 ms

Fundamental frequency: f1=50 Hz Sampling frequency: fs=1000 Hz. (Ts=0.001 s) n: 20. Number of number of samples in a single fundamental frequency period. theta_i: 1500; CT ratio theta_v: 3636.36; VT ratio Simulation Time: 0-119 ms (120 samples ) Fault time: 60 ms Pre fault: 60 ms



3. PROGRAM CODE:

clear all; theta_i=1; % CT ratio theta_v=1; % VT ratio n=20; % number of samples in a single fundamental frequency period %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dT=2*pi/n; for k=1:n, alfa=dT/2+(k-1)*dT; FF(k)=cos(alfa)+sqrt(-1)*sin(alfa); end; FF=-2*FF/n; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% x=readpl452; size(x), y=x'; size(y), iS_af(1,:)=theta_i*filter(FF,1,y(2,:)); % Side S - phase 'a' current after filtration iS_bf(1,:)=theta_i*filter(FF,1,y(3,:)); % Side S - phase 'b' current after filtration iS_cf(1,:)=theta_i*filter(FF,1,y(4,:)); % Side S - phase 'c' current after filtration %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% vS_af(1,:)=theta_i*filter(FF,1,y(5,:)); % Side S - phase 'a' voltage after filtration vS_bf(1,:)=theta_i*filter(FF,1,y(6,:)); % Side S - phase 'b' voltage after filtration vS_cf(1,:)=theta_i*filter(FF,1,y(7,:)); % Side S - phase 'c' voltage after filtration



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% a = -0.5 + 0.5*sqrt(3)*i; IS1 = (iS_af + a*iS_bf + a*a*iS_cf)/3; VS1 = (vS_af + a*vS_bf + a*a*vS_cf)/3; INC_VS1=VS1(61:120)-VS1(1:60); INC_IS1=IS1(61:120)-IS1(1:60); DEL_Z1 = (VS1(61:120)-VS1(1:60))./(IS1(61:120)-IS1(1:60)); figure(1) plot (real(DEL_Z1),imag(DEL_Z1),'ro'); grid on; Hold on; plot (real(DEL_Z1),imag(DEL_Z1),'r-'); plot (real(DEL_Z1(1)),imag(DEL_Z1(1)),'bx'); title('Incremental positive Resistance and Reactance'); xlabel('Time [ms]'); ylabel('Ohm'); figure(2) plot (real(DEL_Z1(1:60)),'r-'); grid on; Hold on; plot (imag(DEL_Z1(1:60)),'go'); plot (real(DEL_Z1(1:60)),'ro'); plot (imag(DEL_Z1(1:60)),'g-'); title('Incremental positive Resistance and Reactance'); xlabel('Time [ms]'); ylabel('Ohm'); end. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



4. GRAPHICS RESULTS: The different graphics obtained from the program are showed down: Fig 1: Task IIIA. Incremental positive resistance. Fig 2: Task IIIA. Incremental positive reactance and resistance. Fig 3: Task IIIB. Incremental positive resistance. Fig 4: Task IIIB. Incremental positive reactance and resistance. Fig 5: Task IIIB. Zoomed Incremental positive reactance and resistance. Fig 1: Task IIIA. Incremental positive resistance. Figure 1 Depicts the resistance or the real part of the impedance during fault in Incremental positive reactance and resistance graph with respect to time.



Fig 2: Task IIIA. Incremental positive reactance and resistance. Figure 2 Depicts both the real and imaginary part of the impedance during fault in Incremental positive reactance and resistance graph with respect to time. Here we can see at 20 ms both the reactance and the resistance tends to negative.



Fig 3: Task IIIB. Incremental positive resistance. Figure 3 Depicts the resistance or the real part of the impedance during fault in Incremental positive reactance and resistance graph .



Fig 4: Task IIIB. Incremental positive reactance and resistance. Figure 4 Depicts both the real and imaginary part of the impedance during fault in Incremental positive reactance and resistance graph with respect to time. Here we can see that the reactance oscillate for certain period of time during fault and it tends to negative along with the resistance.



Fig 5: Task IIIB. Zoomed Incremental positive reactance and resistance.



6.CONCLUSION: From the above figures, after certain period of fault time the impedance which consists of real (resistance) and imaginary (reactance) tends to fall to negative on ohm vs. time plane. It means that the fault is a forward fault. Because for negative impedance (that is both reactance and resistance are negative), It shows that the Impedance lies on third quadrant of real and imaginary axis of impedance. Hence we can conclude with the given task (IIIA, IIIB) that the given fault is a FORWARD FAULT with respect to the fault point.

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POWER SYSTEM FAULTS Fault Direction Discrimination PROJECT-2