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-rw-r--r--3472/CH34/EX34.1/Example34_1.sce30
-rw-r--r--3472/CH34/EX34.2/Example34_2.sce40
-rw-r--r--3472/CH34/EX34.3/Example34_3.sce28
-rw-r--r--3472/CH34/EX34.4/Example34_4.sce31
-rw-r--r--3472/CH34/EX34.5/Example34_5.sce26
-rw-r--r--3472/CH34/EX34.6/Example34_6.sce28
-rw-r--r--3472/CH34/EX34.7/Example34_7.sce28
-rw-r--r--3472/CH34/EX34.8/Example34_8.sce30
8 files changed, 241 insertions, 0 deletions
diff --git a/3472/CH34/EX34.1/Example34_1.sce b/3472/CH34/EX34.1/Example34_1.sce
new file mode 100644
index 000000000..ea02469d3
--- /dev/null
+++ b/3472/CH34/EX34.1/Example34_1.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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.1 :
+// Page number 624
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+V = 6600.0 // Alternator Voltage(V)
+P = 2000.0*10**3 // Rating of alternator(W)
+PF = 0.8 // Power factor of alternator
+X = 12.5 // Alternator reactance(%)
+I = 200.0 // Current protection(A)
+per = 10.0 // Percentage of winding unprotected(%)
+
+// Calculations
+I_fl = P/(3**0.5*V*PF) // Full load current of alternator(A)
+x = X*V/(3**0.5*100*I_fl) // Reactance per phase of alternator(ohm)
+x_per = per/100*x // Reactance of 10% of the winding(ohm)
+NA = V/(3**0.5*per) // Voltage induced in winding(V)
+r = ((NA/I)**2-x_per**2)**0.5 // Neutral earthing reactance(ohm)
+
+// Results
+disp("PART III - EXAMPLE : 8.1 : SOLUTION :-")
+printf("\nNeutral earthing reactance, r = %.2f ohm", r)
diff --git a/3472/CH34/EX34.2/Example34_2.sce b/3472/CH34/EX34.2/Example34_2.sce
new file mode 100644
index 000000000..8d6402589
--- /dev/null
+++ b/3472/CH34/EX34.2/Example34_2.sce
@@ -0,0 +1,40 @@
+// 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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.2 :
+// Page number 624-625
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+MVA = 20.0 // Generator rating(MVA)
+V = 11.0*10**3 // Generator voltage(V)
+ratio_CT = 1200.0/5 // Ratio of current transformer
+I_min_op = 0.75 // Minimum operating current of relay(A)
+R = 6.0 // Neutral point earthing resistance(ohm)
+
+// Calculations
+I_max_fault = ratio_CT*I_min_op // Maximum fault current to operate relay(A)
+x = I_max_fault*3**0.5*100*R/V // Unprotected portion for R = 6 ohm(%)
+R_1 = 3.0 // Neutral point earthing resistance(ohm)
+x_1 = I_max_fault*3**0.5*100*R_1/V // Unprotected portion for R = 3 ohm(%)
+R_3 = 12.0 // Neutral point earthing resistance(ohm)
+x_3 = I_max_fault*3**0.5*100*R_3/V // Unprotected portion for R = 12 ohm(%)
+
+// Results
+disp("PART III - EXAMPLE : 8.2 : SOLUTION :-")
+printf("\nUnprotected portion of each phase of the stator winding against earth fault, x = %.f percent", x)
+printf("\nEffect of varying neutral earthing resistance keeping relay operating current the same :")
+printf("\n (i) R = 3 ohms")
+printf("\n Unprotected portion = %.1f percent", x_1)
+printf("\n Protected portion = %.1f percent", (100-x_1))
+printf("\n (ii) R = 6 ohms")
+printf("\n Unprotected portion = %.f percent", x)
+printf("\n Protected portion = %.f percent", (100-x))
+printf("\n (iii) R = 12 ohms")
+printf("\n Unprotected portion = %.f percent", x_3)
+printf("\n Protected portion = %.f percent", (100-x_3))
diff --git a/3472/CH34/EX34.3/Example34_3.sce b/3472/CH34/EX34.3/Example34_3.sce
new file mode 100644
index 000000000..32e9d468f
--- /dev/null
+++ b/3472/CH34/EX34.3/Example34_3.sce
@@ -0,0 +1,28 @@
+// 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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.3 :
+// Page number 625
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+kVA = 5000.0 // Alternator rating(kVA)
+V = 6600.0 // Alternator voltage(V)
+X = 2.0 // Synchronous reactance per phase(ohm)
+R = 0.5 // Resistance(ohm)
+ofb = 30.0 // Out-of-balance current(%)
+R_n = 6.5 // Resistance of resistor earthed to star point(ohm)
+
+// Calculations
+I_fl = kVA*1000/(3**0.5*V) // Full load current(A)
+I_ofb = ofb/100*I_fl // Out-of-balance current(A)
+x = R_n/((V/(3**0.5*100*I_ofb))-(R/100)) // Portion of winding unprotected(%)
+
+// Results
+disp("PART III - EXAMPLE : 8.3 : SOLUTION :-")
+printf("\nPortion of alternator winding unprotected, x = %.1f percent", x)
diff --git a/3472/CH34/EX34.4/Example34_4.sce b/3472/CH34/EX34.4/Example34_4.sce
new file mode 100644
index 000000000..2f2b9706c
--- /dev/null
+++ b/3472/CH34/EX34.4/Example34_4.sce
@@ -0,0 +1,31 @@
+// 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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.4 :
+// Page number 625
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+I_min = 0.15 // Minimum pick up current of relay(A)
+slope = 12.0 // Slope(%)
+CT_ratio = 400.0/5 // CT ratio
+I_1 = 360.0 // Current(A)
+I_2 = 300.0 // Current(A)
+
+// Calculations
+i_1 = I_1/CT_ratio // Current(A)
+i_2 = I_2/CT_ratio // Current(A)
+percentage = (i_1-i_2)/((i_1+i_2)/2)*100 // Percentage(%)
+
+// Results
+disp("PART III - EXAMPLE : 8.4 : SOLUTION :-")
+if(percentage>slope) then
+ printf("\nRelay would trip the circuit breaker, since the point lie on +ve torque regime")
+else then
+ printf("\nRelay would not trip the circuit breaker, since the point do not lie on +ve torque regime")
+end
diff --git a/3472/CH34/EX34.5/Example34_5.sce b/3472/CH34/EX34.5/Example34_5.sce
new file mode 100644
index 000000000..a360a492f
--- /dev/null
+++ b/3472/CH34/EX34.5/Example34_5.sce
@@ -0,0 +1,26 @@
+// 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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.5 :
+// Page number 625-626
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+MVA = 50.0 // Alternator rating(MVA)
+V = 33.0*10**3 // Alternator voltage(V)
+CT_ratio = 2000.0/5 // CT ratio
+R = 7.5 // Resistor earthed generator neutral(ohm)
+I = 0.5 // Current above which pick up current(A)
+
+// Calculations
+I_min = CT_ratio*I // Minimum current required to operate relay(A)
+x = I_min*R/(V/3**0.5)*100 // Winding unprotected during normal operation(%)
+
+// Results
+disp("PART III - EXAMPLE : 8.5 : SOLUTION :-")
+printf("\nWinding of each phase unprotected against earth when machine operates at nominal voltage, x = %.2f percent", x)
diff --git a/3472/CH34/EX34.6/Example34_6.sce b/3472/CH34/EX34.6/Example34_6.sce
new file mode 100644
index 000000000..8512df487
--- /dev/null
+++ b/3472/CH34/EX34.6/Example34_6.sce
@@ -0,0 +1,28 @@
+// 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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.6 :
+// Page number 626
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+MVA = 50.0 // Alternator rating(MVA)
+kV = 11.0 // Alternator voltage(kV)
+X = 2.0 // Synchronous reactance per phase(ohm)
+R = 0.7 // Resistance per phase(ohm)
+R_n = 5.0 // Resistance through which alternator is earthed(ohm)
+ofb = 25.0 // Out-of-balance current(%)
+
+// Calculations
+I_fl = MVA*1000/(3**0.5*kV) // Full load current(A)
+I_ofb = ofb/100*I_fl // Out-of-balance current(A)
+x = R_n/((kV*1000/(3**0.5*100*I_ofb))-(R/100)) // Portion of winding unprotected(%)
+
+// Results
+disp("PART III - EXAMPLE : 8.6 : SOLUTION :-")
+printf("\nPortion of winding unprotected, x = %.f percent", x)
diff --git a/3472/CH34/EX34.7/Example34_7.sce b/3472/CH34/EX34.7/Example34_7.sce
new file mode 100644
index 000000000..859e083f7
--- /dev/null
+++ b/3472/CH34/EX34.7/Example34_7.sce
@@ -0,0 +1,28 @@
+// 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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.7 :
+// Page number 626-627
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+kV = 11.0 // Alternator voltage(kV)
+MVA = 5.0 // Alternator rating(MVA)
+X = 2.0 // Reactance per phase(ohm)
+ofb = 35.0 // Out-of-balance current(%)
+R_n = 5.0 // Resistance through which star point is earthed(ohm)
+
+// Calculations
+I_fl = MVA*1000/(3**0.5*kV) // Full load current(A)
+I_ofb = ofb/100*I_fl // Out-of-balance current(A)
+x = I_ofb*R_n*100/(kV*1000/3**0.5) // Portion of winding unprotected(%)
+protected = 100.0-x // Winding that is protected against earth faults(%)
+
+// Results
+disp("PART III - EXAMPLE : 8.7 : SOLUTION :-")
+printf("\nPercentage of winding that is protected against earth faults = %.2f percent", protected)
diff --git a/3472/CH34/EX34.8/Example34_8.sce b/3472/CH34/EX34.8/Example34_8.sce
new file mode 100644
index 000000000..561a59f5d
--- /dev/null
+++ b/3472/CH34/EX34.8/Example34_8.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 8: PROTECTION OF ALTERNATORS AND AC MOTORS
+
+// EXAMPLE : 8.8 :
+// Page number 627
+clear ; clc ; close ; // Clear the work space and console
+
+// Given data
+kV = 11.0 // Alternator voltage(kV)
+P = 100.0 // Alternator maximum rating(MW)
+PF = 0.8 // Power factor
+X = 0.1 // Reactance of alternator(pu)
+i = 500.0 // Current(A)
+per = 10.0 // Windings unprotected(%)
+
+// Calculations
+I = P*1000/(3**0.5*kV*PF) // Rated current of alternator(A)
+a = i/I // Relay setting
+I_n = a*I*100/per // Current through neutral(A)
+R = kV*1000/(3**0.5*I_n) // Magnitude of neutral earthing resistance(ohm)
+
+// Results
+disp("PART III - EXAMPLE : 8.8 : SOLUTION :-")
+printf("\nMagnitude of neutral earthing resistance, R = %.2f ohm\n", R)
+printf("\nNOTE: ERROR: Unit of resistance is not mentioned in textbook solution")
generated by cgit (git 2.34.1) at 2024-12-19 14:07:36 +0000