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Diffstat (limited to 'Working_Examples/2777/CH6/EX6.9')
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diff --git a/Working_Examples/2777/CH6/EX6.9/Ex6_9.sce b/Working_Examples/2777/CH6/EX6.9/Ex6_9.sce new file mode 100755 index 0000000..a20cbc0 --- /dev/null +++ b/Working_Examples/2777/CH6/EX6.9/Ex6_9.sce @@ -0,0 +1,71 @@ +
+// ELECTRICAL MACHINES
+// R.K.Srivastava
+// First Impression 2011
+// CENGAGE LEARNING INDIA PVT. LTD
+
+// CHAPTER : 6 : SYNCHRONOUS MACHINES
+
+// EXAMPLE : 6.9
+
+clear ; clc ; close ; // Clear the work space and console
+
+
+// GIVEN DATA
+
+printf("\n EXAMPLE : 6.9 : \n\n Given Data \n");
+printf("\n Voc(kV) 10 10.80 11.50 12.10 12.60 13 14 14.50 14.80 \n");
+printf("\n If(A) 175 200 225 250 275 300 400 450 500 \n\n");
+p = 6; // Total number of Poles of Alternator
+V = 11*10^3; // Operating voltage of the Alternator in Volts
+N = 1500; // speed of the Alternator in RPM
+Ia_scc = 2099; // SCC test Armature current in Amphere at If = 200 A
+If_scc = 200; // SCC test field Rated current in Amphere
+Ia_pt = 2099; // Pottier test Armature current in Amphere at If = 450 A
+If_pt = 450; // Pottier test field Rated current in Amphere
+VA = 40*10^6; // VA rating of the Alternator in Volts-Amphere
+f = 50; // Operating Frequency of the Alternator in Hertz
+pf = 0.8; // Power factor (lagging)
+
+// CALCULATIONS
+// Some of the data obtained from OCC and SCC test Graph or Pottier triangle in Figure6.24 & Page no:-407
+
+v = V/sqrt(3); // Rated phase Voltage in Volts
+I = VA/(sqrt(3)*V); // Full-load phase current in Amphere
+Xl = 0.4481; // Leakage reactance in Ohms From OCC and SCC test Graph or Pottier triangle in Figure6.24 & Page no:-407
+
+
+// For Case(a) General Method
+
+pfa_a = acosd(pf); // Power factor angle in degree
+Er_a = (V/sqrt(3))+(Ia_scc*(cosd(pfa_a)-%i*sind(pfa_a))*Xl); // Induced Voltage in Volts
+R_a = 208.4; A_a = 200; //From OCC the field current required for Er_a (Should be in Line-line Voltage) Er_a = 11043.66 V will get R_a & A_a value Respectively from SCC (Figure6.24 & Page no:-407)
+angle_a = 131.93; // Angle between R_a & A_a (Figure6.25(a) & Page no:-408) = 90'+5.06'+36.87' = 131.93'
+F_a = sqrt((R_a^2)+(A_a^2)-(2*R_a*A_a*cosd(angle_a))); // From phasor diagram in figure 6.25(a) & Page no:-408 the neccessary field excitation in Amphere
+Eo_a = 13720; // Corresponding to field current, F_a = 373 A the open circuit EMF from OCC is 560 V (Figure6.15 & Page no:-386)
+r_a = 100*((Eo_a-V)/V); // Percentage regulation
+
+
+// For Case (b) ASA Method
+
+pfa_b = acosd(pf); // Power factor angle in degree
+Er_b = (V/sqrt(3))+Ia_scc*(cosd(pfa_b)-%i*sind(pfa_b))*Xl; // Induced Voltage in Volts
+R_b = 160; A_b = 200; //From OCC the field current required for Er_b (Should be in Line-line Voltage) Er_b = 11043.66 V will get R_b & A_b value Respectively from SCC (Figure6.24 & Page no:-407)
+angle_b = 126.87; // Angle between R_b2 & A_b2 (Figure6.22b & Page no:-403) = 90'+36.87' = 126.87'
+F_b = sqrt((R_b^2)+(A_b^2)-(2*R_b*A_b*cosd(angle_b))); // From phasor diagram in figure 6.25(b) & Page no:-408 the neccessary field excitation in Amphere
+Eo_b = 13660; // Corresponding to field current ( OF'=OF+FF') F_b = 337.88+15.38=337.88 A the open circuit EMF from OCC is 13660 V (Figure6.15 & Page no:-386)
+r_b = 100*((Eo_b-V)/V); // Percentage regulation
+
+
+// DISPLAY RESULTS
+
+disp(" SOLUTION :-");
+printf("\n For Case (a) General(ZPF) Method \n Induced EMF, EMF = %.f < %.2f V \n",abs(Er_a),atand(imag(Er_a),real(Er_a)))
+printf("\n Percenatge Regulation, R = %.2f Percenatge \n",r_a)
+printf("\n For Case (b) ASA Method \n Induced EMF, EMF = %.f < %.2f V \n",abs(Er_b),atand(imag(Er_b),real(Er_b)))
+printf("\n Percenatge Regulation, R = %.2f Percenatge \n",r_b)
+printf("\n\n [ TEXT BOOK SOLUTION IS PRINTED WRONGLY ( I verified by manual calculation )]\n" );
+printf("\n WRONGLY PRINTED ANSWERS ARE :- For Case (a) General(ZPF) Method (a) Induced EMF = 6376<-5.07 degree instead of %.f < %.2f \n ",abs(Er_a),atand(imag(Er_a),real(Er_a)))
+printf("\n For Case (b) ASA Method (a) Induced EMF = 6376<-5.07 degree instead of %.f < %.2f \n\n ",abs(Er_b),atand(imag(Er_b),real(Er_b)))
+printf(" CALCULATION OF THE POWER ANGLE IS NOT CALCULATED IN THE TEXT BOOK FOR THIS PROBLEM\n ")
+printf("\n INDUCED EMF AND PERCENTAGE REGULATION IS APPROXIMATED VALUE BECACUSE IN THE TEXT BOOK, CALCULATED INDUCED EMF IS WRONGLY PRINTED")
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