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diff --git a/3472/CH27/EX27.1/Example27_1.sce b/3472/CH27/EX27.1/Example27_1.sce
new file mode 100644
index 000000000..330f770b0
--- /dev/null
+++ b/3472/CH27/EX27.1/Example27_1.sce
@@ -0,0 +1,41 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.1 :

+// Page number 466-467

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+V = 500.0                   // Generator voltage(V)

+rating = 10.0               // Rating of the generator(kVA)

+n_up = 1.0/2                // Turns ratio of step-up transformer

+Z_line = complex(1.0,2.0)   // Transmission line impedance(ohm)

+n_down = 10.0/1             // Turns ratio of step-down transformer

+load = complex(2.0,4.0)     // Load(ohm)

+

+// Calculations

+V_base_gen = V                                 // Base voltage(V)

+kVA_base_gen = rating                          // Base rating(kVA)

+I_base_gen = kVA_base_gen*1000/V_base_gen      // Base current(A)

+Z_base_gen = V_base_gen/I_base_gen             // Base impedance(ohm)

+V_base_line = V_base_gen/n_up                  // Voltage base of the transmission line(V)

+kVA_base_line = rating                         // Base rating of transmission line(kVA)

+I_base_line = kVA_base_line*1000/V_base_line   // Base current of transmission line(A)

+Z_base_line = V_base_line/I_base_line          // Base impedance of transmission line(ohm)

+Z_line_1 = Z_line/Z_base_line                  // Impedance of transmission line(p.u)

+V_base_load = V_base_line/n_down               // Base voltage at the load(V)

+kVA_base_load = rating                         // Base rating of load(kVA)

+I_base_load = kVA_base_load*1000/V_base_load   // Base current of load(A)

+Z_base_load = V_base_load/I_base_load          // Base impedance of load(ohm)

+Z_load = load/Z_base_load                      // Load impedance(p.u)

+Z_total = Z_line_1+Z_load                      // Total impedance(p.u)

+I = 1.0/Z_total                                // Current(p.u)

+

+// Results

+disp("PART III - EXAMPLE : 1.1 : SOLUTION :-")

+printf("\nCurrent, I = %.3f∠%.2f° p.u", abs(I),phasemag(I))

diff --git a/3472/CH27/EX27.10/Example27_10.sce b/3472/CH27/EX27.10/Example27_10.sce
new file mode 100644
index 000000000..ee218b356
--- /dev/null
+++ b/3472/CH27/EX27.10/Example27_10.sce
@@ -0,0 +1,30 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.10 :

+// Page number 472

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+kVA_alt = 625.0       // Alternator rating(kVA)

+V_alt = 480.0         // Voltage rating of alternator(V)

+load = 500.0          // Load(kW)

+V_load = 480.0        // Load voltage(V)

+X_st = 8.0/100        // Sub-transient reactance

+

+// Calculations

+kVA_base = 625.0            // Base kVA

+V_base = 480.0              // Base voltage(V)

+I_load = load/kVA_base      // Load cuurent(A)

+V = 1.0                     // Terminal voltage(p.u)

+E_st = V+%i*I_load*X_st     // Sub-transient voltage(p.u)

+I_st = E_st/(%i*X_st)       // Sub-transient current(p.u)

+

+// Results

+disp("PART III - EXAMPLE : 1.10 : SOLUTION :-")

+printf("\nInitial symmetrical rms current at the generator terminal = (%.1f%.1fj) p.u", real(I_st),imag(I_st))

diff --git a/3472/CH27/EX27.11/Example27_11.sce b/3472/CH27/EX27.11/Example27_11.sce
new file mode 100644
index 000000000..e74e57098
--- /dev/null
+++ b/3472/CH27/EX27.11/Example27_11.sce
@@ -0,0 +1,33 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.11 :

+// Page number 472-473

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+X_d_st_G = 0.15      // Sub-transient reactance of generator(p.u)

+X_d_st_M = 0.45      // Sub-transient reactance of motor(p.u)

+X = 0.10             // Leakage reactance of transformer(p.u)

+V = 0.9              // Terminal voltage of the generator(p.u)

+I_G = 1.0            // Output current of the generator(p.u)

+PF = 0.8             // Power factor of the load

+

+// Calculations

+sin_phi = (1-PF**2)**0.5

+I = I_G*(PF+%i*sin_phi)            // Load current(p.u)

+E_st_G = V+%i*I*X_d_st_G           // Sub-transient voltage of the generator(p.u)

+E_st_M = V-%i*I*X_d_st_M           // Sub-transient voltage of the motor(p.u)

+I_st_g = E_st_G/(%i*(X_d_st_G+X))  // Sub-transient current in the generator at fault(p.u)

+I_st_m = E_st_M/(%i*(X_d_st_M-X))  // Sub-transient current in the motor at fault(p.u)

+

+// Results

+disp("PART III - EXAMPLE : 1.11 : SOLUTION :-")

+printf("\nCase(a): Sub-transient current in the fault in generator = %.3f∠%.3f° p.u", abs(I_st_g),phasemag(I_st_g))

+printf("\nCase(b): Sub-transient current in the fault in motor = %.3f∠%.2f° p.u \n", abs(I_st_m),180+phasemag(I_st_m))

+printf("\nNOTE: ERROR: Sub-transient reactance of motor is 0.45 p.u & not 0.35 p.u as mentioned in textbook statement")

diff --git a/3472/CH27/EX27.12/Example27_12.sce b/3472/CH27/EX27.12/Example27_12.sce
new file mode 100644
index 000000000..6106a0e66
--- /dev/null
+++ b/3472/CH27/EX27.12/Example27_12.sce
@@ -0,0 +1,36 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.12 :

+// Page number 473-474

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+kVA_G = 625.0            // Generator rating(kVA)

+V_G = 2.4                // Voltage rating of generator(kV)

+X_st_G = 8.0/100         // Sub-transient reactance of generator

+rating_M = 250.0         // Motor rating(HP)

+V_M = 2.4                // Voltage rating of motor(kV)

+n = 90.0/100             // Efficiency of motor

+X_st_M = 20.0/100        // Sub-transient reactance of motor

+

+// Calculations

+kVA_base = 625.0                                      // Base kVA

+input_M = rating_M*0.746/n                            // Each motor input(kVA)

+X_st_m_pu = X_st_M*kVA_base/input_M                   // Sub-transient reactance of motor(p.u)

+I_base = kVA_base/(3**0.5*V_M)                        // Base current(A)

+Z_th = %i*X_st_m_pu/3*X_st_G/(X_st_m_pu/3+X_st_G)     // Thevenin impedance(p.u)

+I_st = 1.0/Z_th                                       // Initial symmetrical current at F(p.u)

+I_st_g = I_st*(X_st_m_pu/3/(X_st_m_pu/3+X_st_G))      // Fault current rating of generator breaker(p.u)

+I_st_m = (I_st-I_st_g)/3                              // Fault current rating of each motor breaker(p.u)

+

+// Results

+disp("PART III - EXAMPLE : 1.12 : SOLUTION :-")

+printf("\nSub-transient fault current at F = %.2fj p.u", imag(I_st))

+printf("\nFault current rating of generator breaker = %.1fj p.u", imag(I_st_g))

+printf("\nFault current rating of each motor breaker = %.2fj p.u", imag(I_st_m))

diff --git a/3472/CH27/EX27.2/Example27_2.sce b/3472/CH27/EX27.2/Example27_2.sce
new file mode 100644
index 000000000..9de270bce
--- /dev/null
+++ b/3472/CH27/EX27.2/Example27_2.sce
@@ -0,0 +1,42 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.2 :

+// Page number 467-468

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+kV = 33.0                   // Transmission line operating voltage(kV)

+R = 5.0                     // Transmission line resistance(ohm)

+X = 20.0                    // Transmission line reactance(ohm)

+kVA_tr = 5000.0             // Rating of step-up transformer(kVA)

+X_tr = 6.0                  // Reactance of transformer(%)

+kVA_A = 10000.0             // Rating of alternator A(kVA)

+X_A = 10.0                  // Reactance of alternator A(%)

+kVA_B = 5000.0              // Rating of alternator B(kVA)

+X_B = 7.5                   // Reactance of alternator B(%)

+

+// Calculations

+kVA_base = kVA_A                                      // Base rating(kVA)

+X_gen_A = X_A*kVA_base/kVA_A                          // Reactance of generator A(%)

+X_gen_B = X_B*kVA_base/kVA_B                          // Reactance of generator B(%)

+X_trans = X_tr*kVA_base/kVA_tr                        // Reactance of transformer(%)

+X_per = kVA_base*X/(10*kV**2)                         // X(%)

+R_per = kVA_base*R/(10*kV**2)                         // R(%)

+Z_F1 = (X_gen_A*X_gen_B/(X_gen_A+X_gen_B))+X_trans    // Impedance upto fault(%)

+kVA_F1 = kVA_base*(100/Z_F1)                          // Short-circuit kVA fed into the fault(kVA)

+R_per_F2 = R_per                                      // R(%)

+X_per_F2 = X_per+Z_F1                                 // X(%)

+Z_F2 = (R_per_F2**2+X_per_F2**2)**0.5                 // Total impedance upto F2(%)

+kVA_F2 = kVA_base*(100/Z_F2)                          // Short-circuit kVA fed into the fault at F2(kVA)

+

+// Results

+disp("PART III - EXAMPLE : 1.2 : SOLUTION :-")

+printf("\nCase(a): kVA at a short-circuit fault between phases at the HV terminal of transformers = %.f kVA", kVA_F1)

+printf("\nCase(b): kVA at a short-circuit fault between phases at load end of transmission line = %.f kVA \n", kVA_F2)

+printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here & approximation in textbook")

diff --git a/3472/CH27/EX27.3/Example27_3.sce b/3472/CH27/EX27.3/Example27_3.sce
new file mode 100644
index 000000000..f219efe4a
--- /dev/null
+++ b/3472/CH27/EX27.3/Example27_3.sce
@@ -0,0 +1,82 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.3 :

+// Page number 468-469

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+kVA_a = 40000.0          // Capacity of transmission line(kVA)

+x_a = 10.0               // Reactance of transmission line(%)

+kVA_b = 20000.0          // Capacity of transmission line(kVA)

+x_b = 5.0                // Reactance of transmission line(%)

+kVA_c = 50000.0          // Capacity of transmission line(kVA)

+x_c = 20.0               // Reactance of transmission line(%)

+kVA_d = 30000.0          // Capacity of transmission line(kVA)

+x_d = 15.0               // Reactance of transmission line(%)

+kVA_e = 10000.0          // Capacity of transmission line(kVA)

+x_e = 6.0                // Reactance of transmission line(%)

+kVA_T1 = 150000.0        // Capacity of transformer(kVA)

+x_T1 = 10.0              // Reactance of transformer(%)

+kVA_T2 = 50000.0         // Capacity of transformer(kVA)

+x_T2 = 8.0               // Reactance of transformer(%)

+kVA_T3 = 20000.0         // Capacity of transformer(kVA)

+x_T3 = 5.0               // Reactance of transformer(%)

+kVA_GA = 150000.0        // Capacity of generator(kVA)

+x_sA = 90.0              // Synchronous reactance of generator(%)

+x_tA = 30.0              // Transient reactance of generator(%)

+kVA_GB = 50000.0         // Capacity of generator(kVA)

+x_sB = 50.0              // Synchronous reactance of generator(%)

+x_tB = 17.5              // Transient reactance of generator(%)

+V = 33.0                 // Feeder voltage(kV)

+

+// Calculations

+kVA_base = 200000.0                                  // Base rating(kVA)

+X_a = kVA_base/kVA_a*x_a                             // Reactance(%)

+X_b = kVA_base/kVA_b*x_b                             // Reactance(%)

+X_c = kVA_base/kVA_c*x_c                             // Reactance(%)

+X_d = kVA_base/kVA_d*x_d                             // Reactance(%)

+X_e = kVA_base/kVA_e*x_e                             // Reactance(%)

+X_T1 = kVA_base/kVA_T1*x_T1                          // Reactance(%)

+X_T2 = kVA_base/kVA_T2*x_T2                          // Reactance(%)

+X_T3 = kVA_base/kVA_T3*x_T3                          // Reactance(%)

+X_sA = kVA_base/kVA_GA*x_sA                          // Synchronous reactance(%)

+X_tA = kVA_base/kVA_GA*x_tA                          // Transient reactance(%)

+X_sB = kVA_base/kVA_GB*x_sB                          // Synchronous reactance(%)

+X_tB = kVA_base/kVA_GB*x_tB                          // Transient reactance(%)

+X_eq_ab = X_a+X_b                                    // Equivalent reactance of transmission lines a & b(%)

+X_eq_abc = X_eq_ab*X_c/(X_eq_ab+X_c)                 // Equivalent reactance of transmission line c with series combination of a & b(%)

+X_CF = (X_eq_abc+X_sA)*X_d/(X_eq_abc+X_sA+X_d)       // Total reactance b/w sub-station C & F(%)

+// Case(i)

+X_tr_genA = kVA_base/kVA_GA*x_tA                     // Reactance in transient state of generator A(%)

+X_T1_tr = kVA_base/kVA_T1*x_T1                       // Reactance in transient state of transformer T1(%)

+X_CF_tr = X_CF                                       // Total reactance in transient state b/w sub-station C & F(%)

+X_eq_tAF = X_tr_genA+X_T1_tr+X_CF_tr                 // Equivalent transient reactance from generator A to substation F(%)

+X_tr_genB = kVA_base/kVA_GB*x_tB                     // Reactance in transient state of generator B(%)

+X_T2_tr = kVA_base/kVA_T2*x_T2                       // Reactance in transient state of transformer T2(%)

+X_eq_tBF = X_tr_genB+X_T2_tr                         // Equivalent transient reactance from generator B to substation F(%)

+X_eq_tF = X_eq_tAF*X_eq_tBF/(X_eq_tAF+X_eq_tBF)      // Equivalent transient reactance upto substation F(%)

+X_eq_tfault = X_eq_tF+X_T3                           // Equivalent transient reactance upto fault point(%)

+kVA_t_sc = kVA_base/X_eq_tfault*100                  // Transient short circuit kVA(kVA)

+I_t_sc = kVA_t_sc/(3**0.5*V)                         // Transient short circuit rms current(A)

+I_t_sc_peak = 2**0.5*I_t_sc                          // Peak value of transient short circuit current(A)

+// Case(ii)

+X_S_genA = kVA_base/kVA_GA*x_sA                      // Reactance in steady state of generator A(%)

+X_eq_SAF = X_S_genA+X_T1+X_CF                        // Equivalent steady state reactance from generator A to substation F(%)

+X_eq_SBF = X_sB+X_T2                                 // Equivalent steady state reactance from generator B to substation F(%)

+X_eq_SF = X_eq_SAF*X_eq_SBF/(X_eq_SAF+X_eq_SBF)      // Equivalent steady state reactance upto substation F(%)

+X_eq_Sfault = X_eq_SF+X_T3                           // Equivalent steady state reactance upto fault point(%)

+kVA_S_sc = kVA_base/X_eq_Sfault*100                  // Steady state short circuit kVA(kVA)

+I_S_sc = kVA_S_sc/(3**0.5*V)                         // Sustained short circuit rms current(A)

+I_S_sc_peak = 2**0.5*I_S_sc                          // Peak value of sustained short circuit current(A)

+

+// Results

+disp("PART III - EXAMPLE : 1.3 : SOLUTION :-")

+printf("\nCase(i) : Transient short circuit current at X = %.f A (peak value)", I_t_sc_peak)

+printf("\nCase(ii): Sustained short circuit current at X = %.f A (peak value) \n", I_S_sc_peak)

+printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here")

diff --git a/3472/CH27/EX27.4/Example27_4.sce b/3472/CH27/EX27.4/Example27_4.sce
new file mode 100644
index 000000000..03026583b
--- /dev/null
+++ b/3472/CH27/EX27.4/Example27_4.sce
@@ -0,0 +1,42 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.4 :

+// Page number 469-470

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+kVA_gen = 21000.0       // Generator rating(kVA)

+kV_gen = 13.8           // Voltage rating of generator(kV)

+X_tr_gen = 30.0         // Transient reactance of generator(%)

+kVA_trans = 7000.0      // Transformer rating(kVA)

+kV_trans_lv = 13.8      // LV voltage rating of transformer(kV)

+kV_trans_hv = 66.0      // HV voltage rating of transformer(kV)

+X_trans = 8.4           // Reactance of transformer(%)

+l = 50.0                // Tie line length(miles)

+x = 0.848               // Reactance of tie line(ohm/mile)

+l_fault = 20.0          // Location of fault from station A(miles)

+

+// Calculations

+kVA_base = kVA_gen                             // Base rating(kVA)

+X_A = X_tr_gen                                 // Reactance of generator A(%)

+X_B = X_tr_gen                                 // Reactance of generator B(%)

+X_T1 = 3.0*X_trans                             // Reactance of transformer T1(%)

+X_T2 = 3.0*X_trans                             // Reactance of transformer T2(%)

+X_1 = kVA_base/(10*kV_trans_hv**2)*x*l_fault   // Reactance(%)

+X_2 = X_1*(l-l_fault)/l_fault                  // Reactance(%)

+X_AF = X_A+X_T1+X_1                            // Resultant reactance A to F(%)

+X_BF = X_B+X_T2+X_2                            // Resultant reactance B to F(%)

+X_eq_fault = X_AF*X_BF/(X_AF+X_BF)             // Equivalent reactance upto fault(%)

+kVA_SC = kVA_base/X_eq_fault*100               // Short circuit kVA((kVA)

+I_SC = kVA_SC/(3**0.5*kV_trans_hv)             // Short circuit current(A)

+

+// Results

+disp("PART III - EXAMPLE : 1.4 : SOLUTION :-")

+printf("\nShort circuit current = %.f A \n", I_SC)

+printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here")

diff --git a/3472/CH27/EX27.5/Example27_5.sce b/3472/CH27/EX27.5/Example27_5.sce
new file mode 100644
index 000000000..f48af78f8
--- /dev/null
+++ b/3472/CH27/EX27.5/Example27_5.sce
@@ -0,0 +1,81 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.5 :

+// Page number 470-471

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+MVA_G1 = 100.0            // Generator rating(MVA)

+X_G1 = 30.0               // Reactance of generator(%)

+MVA_G2 = 150.0            // Generator rating(MVA)

+X_G2 = 20.0               // Reactance of generator(%)

+MVA_G3 = 200.0            // Generator rating(MVA)

+X_G3 = 15.0               // Reactance of generator(%)

+MVA_T1 = 150.0            // Transformer rating(MVA)

+X_T1 = 10.0               // Reactance of transformer(%)

+MVA_T2 = 175.0            // Transformer rating(MVA)

+X_T2 = 8.0                // Reactance of transformer(%)

+MVA_T3 = 200.0            // Transformer rating(MVA)

+X_T3 = 6.0                // Reactance of transformer(%)

+MVA_T4 = 100.0            // Transformer rating(MVA)

+X_T4 = 5.0                // Reactance of transformer(%)

+MVA_T5 = 150.0            // Transformer rating(MVA)

+X_T5 = 5.0                // Reactance of transformer(%)

+Z_L1 = complex(0.5,1.0)   // Line impedance(ohm/km)

+L1 = 100.0                // Line length(km)

+Z_L2 = complex(0.4,1.2)   // Line impedance(ohm/km)

+L2 = 50.0                 // Line length(km)

+Z_L3 = complex(0.4,1.2)   // Line impedance(ohm/km)

+L3 = 50.0                 // Line length(km)

+Z_L4 = complex(0.3,1.0)   // Line impedance(ohm/km)

+L4 = 60.0                 // Line length(km)

+kV_L1 = 220.0             // Voltage towards line(kV)

+kV_L2 = 220.0             // Voltage towards line(kV)

+kV_L3 = 132.0             // Voltage towards line(kV)

+kV_L4 = 132.0             // Voltage towards line(kV)

+

+// Calculations

+MVA_base = 200.0                         // Base rating(MVA)

+X_d_G1 = (MVA_base/MVA_G1)*(X_G1/100)    // Reactance of generator(p.u)

+X_d_G2 = (MVA_base/MVA_G2)*(X_G2/100)    // Reactance of generator(p.u)

+X_d_G3 = (MVA_base/MVA_G3)*(X_G3/100)    // Reactance of generator(p.u)

+X_T_1 = (MVA_base/MVA_T1)*(X_T1/100)     // Reactance of transformer(p.u)

+X_T_2 = (MVA_base/MVA_T2)*(X_T2/100)     // Reactance of transformer(p.u)

+X_T_3 = (MVA_base/MVA_T3)*(X_T3/100)     // Reactance of transformer(p.u)

+X_T_4 = (MVA_base/MVA_T4)*(X_T4/100)     // Reactance of transformer(p.u)

+X_T_5 = (MVA_base/MVA_T5)*(X_T5/100)     // Reactance of transformer(p.u)

+Z_L1_base = kV_L1**2/MVA_base            // L1 base impedance(ohm)

+Z_L_1 = Z_L1*L1/Z_L1_base                // Line impedance(p.u)

+Z_L2_base = kV_L2**2/MVA_base            // L2 base impedance(ohm)

+Z_L_2 = Z_L2*L2/Z_L2_base                // Line impedance(p.u)

+Z_L3_base = kV_L3**2/MVA_base            // L3 base impedance(ohm)

+Z_L_3 = Z_L3*L3/Z_L3_base                // Line impedance(p.u)

+Z_L4_base = kV_L4**2/MVA_base            // L4 base impedance(ohm)

+Z_L_4 = Z_L4*L4/Z_L4_base                // Line impedance(p.u)

+

+// Results

+disp("PART III - EXAMPLE : 1.5 : SOLUTION :-")

+printf("\np.u values of the single line diagram are as below")

+printf("\nGenerators p.u reactances :")

+printf("\n X_d_G1 = %.1f p.u", X_d_G1)

+printf("\n X_d_G2 = %.3f p.u", X_d_G2)

+printf("\n X_d_G3 = %.2f p.u", X_d_G3)

+printf("\nTransformers p.u reactances :")

+printf("\n X_T1 = %.3f p.u", X_T_1)

+printf("\n X_T2 = %.4f p.u", X_T_2)

+printf("\n X_T3 = %.2f p.u", X_T_3)

+printf("\n X_T4 = %.1f p.u", X_T_4)

+printf("\n X_T5 = %.3f p.u", X_T_5)

+printf("\nLines p.u impedances :")

+printf("\n Z_L1 = (%.3f + %.3fj) p.u", real(Z_L_1),imag(Z_L_1))

+printf("\n Z_L2 = (%.3f + %.3fj) p.u", real(Z_L_2),imag(Z_L_2))

+printf("\n Z_L3 = (%.3f + %.3fj) p.u", real(Z_L_3),imag(Z_L_3))

+printf("\n Z_L4 = (%.3f + %.3fj) p.u \n", real(Z_L_4),imag(Z_L_4))

+printf("\nNOTE: ERROR: (1). Reactance of T2 is 8 percent & not 1 percent as mentioned in the textbook problem statement")

+printf("\n             (2). Several calculation mistakes in the textbook")

diff --git a/3472/CH27/EX27.6/Example27_6.sce b/3472/CH27/EX27.6/Example27_6.sce
new file mode 100644
index 000000000..746c48c42
--- /dev/null
+++ b/3472/CH27/EX27.6/Example27_6.sce
@@ -0,0 +1,43 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.6 :

+// Page number 471

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+kVA_gen = 21000.0       // Generator rating(kVA)

+kV_gen = 13.8           // Voltage rating of generator(kV)

+X_tr_gen = 30.0         // Transient reactance of generator(%)

+kVA_trans = 7000.0      // Transformer rating(kVA)

+kV_trans_lv = 13.8      // LV voltage rating of transformer(kV)

+kV_trans_hv = 66.0      // HV voltage rating of transformer(kV)

+X_trans = 8.4           // Reactance of transformer(%)

+l = 50.0                // Tie line length(miles)

+x = 0.848               // Reactance of tie line(ohm/mile)

+l_fault = 20.0          // Location of fault from station A(miles)

+

+// Calculations

+kVA_base = kVA_gen                                     // Base rating(kVA)

+kV_base_lv = kV_trans_lv                               // Base voltage on L.V side(kV)

+kV_base_hv = kV_trans_hv                               // Base voltage on H.V side(kV)

+Z_gen_pu = %i*X_tr_gen/100                             // Impedance of generator(p.u)

+Z_trans_pu = %i*X_trans*3/100                          // Impedance of transformer(p.u)

+Z_F_left = %i*x*l_fault*kVA_base/(kV_base_hv**2*1000)  // Impedance of line to left of fault F(p.u)

+Z_F_right = Z_F_left*(l-l_fault)/l_fault               // Impedance of line to right of fault(p.u)

+Z_AF = Z_gen_pu+Z_trans_pu+Z_F_left                    // Impedance(p.u)

+Z_BF = Z_gen_pu+Z_trans_pu+Z_F_right                   // Impedance(p.u)

+Z_eq = Z_AF*Z_BF/(Z_AF+Z_BF)                           // Equivalent impedance(p.u)

+I_F = 1.0/abs(Z_eq)                                    // Fault current(p.u)

+I_base = kVA_base/(3**0.5*kV_base_hv)                  // Base current(A)

+I_F_actual = I_F*I_base                                // Actual fault current(A)

+

+// Results

+disp("PART III - EXAMPLE : 1.6 : SOLUTION :-")

+printf("\nActual fault current = %.f A \n", I_F_actual)

+printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here")

diff --git a/3472/CH27/EX27.7/Example27_7.sce b/3472/CH27/EX27.7/Example27_7.sce
new file mode 100644
index 000000000..a61e5ba94
--- /dev/null
+++ b/3472/CH27/EX27.7/Example27_7.sce
@@ -0,0 +1,38 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.7 :

+// Page number 471-472

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+MVA_G1 = 50.0         // Generator rating(MVA)

+kV_G1 = 15.0          // Voltage rating of generator(kV)

+X_G1 = 0.2            // Reactance of generator(p.u)

+MVA_G2 = 25.0         // Generator rating(MVA)

+kV_G2 = 15.0          // Voltage rating of generator(kV)

+X_G2 = 0.2            // Reactance of generator(p.u)

+kV_T = 66.0           // Voltage rating of transformer(kV)

+X_T = 0.1             // Reactance of transformer(p.u)

+kV_fault = 66.0       // Voltage at fault occurence(kV)

+kv_base = 69.0        // Base voltage(kV)

+MVA_base = 100.0      // Base MVA

+

+// Calculations

+X_d_G1 = X_G1*MVA_base/MVA_G1             // Sub-transient reactance referred to 100 MVA(p.u)

+E_G1 = kV_fault/kv_base                   // Voltage(p.u)

+X_d_G2 = X_G2*MVA_base/MVA_G2             // Sub-transient reactance referred to 100 MVA(p.u)

+E_G2 = kV_fault/kv_base                   // Voltage(p.u)

+X_net = X_d_G1*X_d_G2/(X_d_G1+X_d_G2)     // Net sub-transient reactance(p.u)

+E_g = (E_G1+E_G2)/2                       // Net voltage(p.u). NOTE: Not sure how this comes

+I_fault = E_g/(%i*(X_net+X_T))            // Sub-transient fault current(p.u)

+

+// Results

+disp("PART III - EXAMPLE : 1.7 : SOLUTION :-")

+printf("\nSub-transient fault current = %.3fj p.u \n", imag(I_fault))

+printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here")

diff --git a/3472/CH27/EX27.8/Example27_8.sce b/3472/CH27/EX27.8/Example27_8.sce
new file mode 100644
index 000000000..9e5bfe023
--- /dev/null
+++ b/3472/CH27/EX27.8/Example27_8.sce
@@ -0,0 +1,32 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.8 :

+// Page number 472

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+X_d_st = 0.2       // Sub-transient reactance(p.u)

+X_d_t = 0.4        // Transient reactance(p.u)

+X_d = 1.0          // Direct axis reactance(p.u)

+I_pu = 1.0         // Load current(p.u)

+PF = 0.80          // Lagging power factor

+

+// Calculations

+V = 1.0                     // Terminal voltage(p.u)

+sin_phi = (1-PF**2)**0.5

+I = I_pu*(PF-%i*sin_phi)    // Load current(p.u)

+E_st = V+%i*I*X_d_st        // Voltage behind sub-transient reactance(p.u)

+E_t = V+%i*I*X_d_t          // Voltage behind transient reactance(p.u)

+E = V+%i*I*X_d              // Voltage behind direct axis reactance(p.u)

+

+// Results

+disp("PART III - EXAMPLE : 1.8 : SOLUTION :-")

+printf("\nVoltage behind sub-transient reactance = %.2f∠%.2f° p.u", abs(E_st),phasemag(E_st))

+printf("\nVoltage behind transient reactance = %.2f∠%.2f° p.u", abs(E_t),phasemag(E_t))

+printf("\nVoltage behind direct axis reactance, E = %.2f∠%.2f° p.u", abs(E),phasemag(E))

diff --git a/3472/CH27/EX27.9/Example27_9.sce b/3472/CH27/EX27.9/Example27_9.sce
new file mode 100644
index 000000000..06277625e
--- /dev/null
+++ b/3472/CH27/EX27.9/Example27_9.sce
@@ -0,0 +1,35 @@
+// A Texbook on POWER SYSTEM ENGINEERING

+// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar

+// DHANPAT RAI & Co.

+// SECOND EDITION 

+

+// PART III : SWITCHGEAR AND PROTECTION

+// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS

+

+// EXAMPLE : 1.9 :

+// Page number 472

+clear ; clc ; close ; // Clear the work space and console

+

+// Given data

+kVA_G = 7500.0         // Generator rating(kVA)

+kV_G = 6.9             // Voltage rating of generator(kV)

+X_d_st = 9.0/100       // Sub-transient reactance of generator

+X_d_t = 15.0/100       // Transient reactance of generator

+X_d = 100.0            // Synchronous reactance of generator(%)

+kVA_T = 7500.0         // Transformer rating(kVA)

+kV_T_delta = 6.9       // Voltage rating of transformer delta side(kV)

+kV_T_wye = 115.0       // Voltage rating of transformer wye side(kV)

+X = 10.0/100           // Transformer reactance

+

+// Calculations

+I_base_ht = kVA_T/(3**0.5*kV_T_wye)     // Base current at ht side(A)

+I_base_lt = kVA_T/(3**0.5*kV_T_delta)   // Base current at lt side(A)

+I_f_st = 1.0/(%i*(X_d_st+X))            // Sub-transient current after fault(p.u)

+I_f_ht = abs(I_f_st)*I_base_ht          // Initial fault current in h.t side(A)

+I_f_lt = abs(I_f_st)*I_base_lt          // Initial fault current in l.t side(A)

+

+// Results

+disp("PART III - EXAMPLE : 1.9 : SOLUTION :-")

+printf("\nInitial symmetrical rms current in the h.v side = %.f A", I_f_ht)

+printf("\nInitial symmetrical rms current in the l.v side = %.f A \n", I_f_lt)

+printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here")