From 7f60ea012dd2524dae921a2a35adbf7ef21f2bb6 Mon Sep 17 00:00:00 2001 From: prashantsinalkar Date: Tue, 10 Oct 2017 12:27:19 +0530 Subject: initial commit / add all books --- 3574/CH9/EX9.1/EX9_1.png | Bin 0 -> 162548 bytes 3574/CH9/EX9.1/EX9_1.sce | 81 +++++++++++++++++++++++++++++++++++++++++++++ 3574/CH9/EX9.10/EX9_10.png | Bin 0 -> 151532 bytes 3574/CH9/EX9.10/EX9_10.sce | 68 +++++++++++++++++++++++++++++++++++++ 3574/CH9/EX9.11/EX9_11.png | Bin 0 -> 132137 bytes 3574/CH9/EX9.11/EX9_11.sce | 39 ++++++++++++++++++++++ 3574/CH9/EX9.2/EX9_2.png | Bin 0 -> 111877 bytes 3574/CH9/EX9.2/EX9_2.sce | 23 +++++++++++++ 3574/CH9/EX9.3/EX9_3.png | Bin 0 -> 125293 bytes 3574/CH9/EX9.3/EX9_3.sce | 32 ++++++++++++++++++ 3574/CH9/EX9.4/EX9_4.png | Bin 0 -> 131122 bytes 3574/CH9/EX9.4/EX9_4.sce | 37 +++++++++++++++++++++ 3574/CH9/EX9.5/EX9_5.png | Bin 0 -> 120464 bytes 3574/CH9/EX9.5/EX9_5.sce | 29 ++++++++++++++++ 3574/CH9/EX9.6/EX9_6.png | Bin 0 -> 157498 bytes 3574/CH9/EX9.6/EX9_6.sce | 42 +++++++++++++++++++++++ 3574/CH9/EX9.7/EX9_7.png | Bin 0 -> 136737 bytes 3574/CH9/EX9.7/EX9_7.sce | 34 +++++++++++++++++++ 3574/CH9/EX9.8/EX9_8.png | Bin 0 -> 125220 bytes 3574/CH9/EX9.8/EX9_8.sce | 30 +++++++++++++++++ 3574/CH9/EX9.9/EX9_9.png | Bin 0 -> 153294 bytes 3574/CH9/EX9.9/EX9_9.sce | 68 +++++++++++++++++++++++++++++++++++++ 22 files changed, 483 insertions(+) create mode 100644 3574/CH9/EX9.1/EX9_1.png create mode 100644 3574/CH9/EX9.1/EX9_1.sce create mode 100644 3574/CH9/EX9.10/EX9_10.png create mode 100644 3574/CH9/EX9.10/EX9_10.sce create mode 100644 3574/CH9/EX9.11/EX9_11.png create mode 100644 3574/CH9/EX9.11/EX9_11.sce create mode 100644 3574/CH9/EX9.2/EX9_2.png create mode 100644 3574/CH9/EX9.2/EX9_2.sce create mode 100644 3574/CH9/EX9.3/EX9_3.png create mode 100644 3574/CH9/EX9.3/EX9_3.sce create mode 100644 3574/CH9/EX9.4/EX9_4.png create mode 100644 3574/CH9/EX9.4/EX9_4.sce create mode 100644 3574/CH9/EX9.5/EX9_5.png create mode 100644 3574/CH9/EX9.5/EX9_5.sce create mode 100644 3574/CH9/EX9.6/EX9_6.png create mode 100644 3574/CH9/EX9.6/EX9_6.sce create mode 100644 3574/CH9/EX9.7/EX9_7.png create mode 100644 3574/CH9/EX9.7/EX9_7.sce create mode 100644 3574/CH9/EX9.8/EX9_8.png create mode 100644 3574/CH9/EX9.8/EX9_8.sce create mode 100644 3574/CH9/EX9.9/EX9_9.png create mode 100644 3574/CH9/EX9.9/EX9_9.sce (limited to '3574/CH9') diff --git a/3574/CH9/EX9.1/EX9_1.png b/3574/CH9/EX9.1/EX9_1.png new file mode 100644 index 000000000..b7aa5ceac Binary files /dev/null and b/3574/CH9/EX9.1/EX9_1.png differ diff --git a/3574/CH9/EX9.1/EX9_1.sce b/3574/CH9/EX9.1/EX9_1.sce new file mode 100644 index 000000000..453a97c1f --- /dev/null +++ b/3574/CH9/EX9.1/EX9_1.sce @@ -0,0 +1,81 @@ +// Example 9.1 +// Determine (a) Turbine torque supplied to the alternator (b) Excitation +// voltage (c) Active and reactive components of apparent power (d) Power +// factor (e) Neglecting saturation effects, excitation voltage if the field +// current is reduced to 85% of its voltage in (a) (f) Turbine speed. +// Page No. 342 + +clc; +clear; +close; + +// Given data +hp=112000; // Power input +n=746*3600; // Speed +VT=460; // 3-Phase supply voltage +Pout=112000; // Power +Xs=1.26; // Synchronous reactnace +delta=25; // Power angle +eta=0.85; // Percent reduction factor +P=2; // Number of poles +f=60; // Frequnecy + +// (a) Turbine torque supplied to the alternator +T=(hp*5252)/n; + +// (b) Excitation voltage +Vt=VT/sqrt(3); // Voltage/phase +Ef=(Pout*Xs)/(3*Vt*sind(delta)); + +// (c) Active and reactive components of apparent power +// Vt=Ef-Ia*j*Xs +// Solving for Vt-Ef +Vt_Mag=Vt; +Vt_Ang=0; +Ef_Mag=Ef; +Ef_Ang=delta; +// +N01=Ef_Mag+%i*Ef_Ang; // Ef in polar form +N02=Vt_Mag+%i*Vt_Ang; // Vt in polar for + +N01_R=Ef_Mag*cos(-Ef_Ang*%pi/180); // Real part of complex number Ef +N01_I=Ef_Mag*sin(Ef_Ang*%pi/180); //Imaginary part of complex number Ef + +N02_R=Vt_Mag*cos(-Vt_Ang*%pi/180); // Real part of complex number Vt +N02_I=Vt_Mag*sin(Vt_Ang*%pi/180); //Imaginary part of complex number Vt + +FinalNo_R=N01_R-N02_R; +FinalNo_I=N01_I-N02_I; +FinNum=FinalNo_R+%i*FinalNo_I; + +// Now FinNum/Xs in polar form +FinNum_Mag=sqrt(real(FinNum)^2+imag(FinNum)^2); // Magnitude part +FinNum_Ang = atan(imag(FinNum),real(FinNum))*180/%pi; // Angle part
 +Ia_Mag=FinNum_Mag/Xs; +Ia_Ang=FinNum_Ang-90; + +// Computation of S=3*Vt*Ia* +S_Mag=3*Vt_Mag*Ia_Mag; +S_Ang=Vt_Ang+-Ia_Ang; + +// Polar to complex form +S_R=S_Mag*cos(-S_Ang*%pi/180); // Real part of complex number S +S_I=S_Mag*sin(S_Ang*%pi/180); // Imaginary part of complex number S + +// (d) Power factor +Fp=cosd(Ia_Ang); + +// (e) Excitation voltage +Efnew=eta*Ef_Mag; + +// (f) Turbine speed +ns=120*f/P; + +// Display result on command window +printf("\n Turbine torque supplied to the alternator = %0.1f lb-ft ",T); +printf("\n Excitation voltage = %0.1f V/phase ",Ef); +printf("\n Active components of apparent power= %0.0f kW ",S_R/1000); +printf("\n Reactive components of apparent power= %0.1f kvar lagging ",S_I/1000); +printf("\n Power factor = %0.2f lagging ",Fp); +printf("\n Excitation voltage new = %0.1f V/phase ",Efnew); +printf("\n Turbine speed = %0.0f r/min ",ns); diff --git a/3574/CH9/EX9.10/EX9_10.png b/3574/CH9/EX9.10/EX9_10.png new file mode 100644 index 000000000..8cd2c84bd Binary files /dev/null and b/3574/CH9/EX9.10/EX9_10.png differ diff --git a/3574/CH9/EX9.10/EX9_10.sce b/3574/CH9/EX9.10/EX9_10.sce new file mode 100644 index 000000000..0adf55f18 --- /dev/null +++ b/3574/CH9/EX9.10/EX9_10.sce @@ -0,0 +1,68 @@ +// Example 9.10 +// Repeat the example 9.9 assuming 90 % leading power factor +// Determine (a) Excitation voltage (b) Power angle (c) No load voltage, +// assuming the field current is not changed (d) Voltage regulation (e) No load +// voltage if the field current is reduced to 80% of its value at rated load. +// Page 372 + +clc; +clear; +close; + +// Given data +V=4800; // Voltage of synchronous generator +PF=0.900; // Lagging power factor +S_Mag=1000000/3; +Xa_Mag=13.80; // Synchronous reactance +Xa_Ang=90; +Vt_Ang=0; + +// (a) Excitation voltage +Vt=V/sqrt(3); +Theta=acosd(PF); // Angle +Ia_Magstar=S_Mag/Vt; // Magnitude of curent +Ia_Angstar=Theta-0; // Angle of current +Ia_Mag=Ia_Magstar; +Ia_Ang=Ia_Angstar; + +// Ef=Vt+Ia*j*Xa +// First compute Ia*Xa +IaXa_Mag=Ia_Mag*Xa_Mag; +IaXa_Ang=Ia_Ang+Xa_Ang; +// Polar to Complex form for IaXa +IaXa_R=IaXa_Mag*cos(-IaXa_Ang*%pi/180); // Real part of complex number +IaXa_I=IaXa_Mag*sin(IaXa_Ang*%pi/180); // Imaginary part of complex number +// Vt term in polar form +Vt_Mag=Vt; +Vt_Ang=Vt_Ang; +// Polar to Complex form for Vt +Vt_R=Vt_Mag*cos(-Vt_Ang*%pi/180); // Real part of complex number +Vt_I=Vt_Mag*sin(Vt_Ang*%pi/180); // Imaginary part of complex number +// Ef in complex form +Ef_R=IaXa_R+Vt_R; +Ef_I=IaXa_I+Vt_I; +Ef=Ef_R+%i*Ef_I; +// Complex to Polar form for Ef +Ef_Mag=sqrt(real(Ef)^2+imag(Ef)^2); // Magnitude part +Ef_Ang= atan(imag(Ef),real(Ef))*180/%pi; // Angle part
 + +// (b) Power angle +PA=Ef_Ang; + +// (c) No load voltage, assuming the field current is not changed +// From figure 9.23 (b) +VolAxis=Vt_Mag/30; // The scale at the given voltage axis +Ef_loc=Ef_Mag/VolAxis; // Location of Ef voltage +Vnl=29*VolAxis; // No load voltage + +// (d) Voltage regulation +VR=(Vnl-Vt)/Vt*100; + + +// Display result on command window +printf("\n Excitation voltage = %0.0f V ",Ef_Mag); +printf("\n Power angle = %0.1f deg ",PA); +printf("\n No load voltage = %0.0f V ",Vnl); +printf("\n Voltage regulation = %0.2f Percent ",VR); +disp('The leading power factor resulted in a negativr voltage regulation') + diff --git a/3574/CH9/EX9.11/EX9_11.png b/3574/CH9/EX9.11/EX9_11.png new file mode 100644 index 000000000..0f56c7065 Binary files /dev/null and b/3574/CH9/EX9.11/EX9_11.png differ diff --git a/3574/CH9/EX9.11/EX9_11.sce b/3574/CH9/EX9.11/EX9_11.sce new file mode 100644 index 000000000..df7931fc9 --- /dev/null +++ b/3574/CH9/EX9.11/EX9_11.sce @@ -0,0 +1,39 @@ +// Example 9.11 +// Determine (a) Equivalent armature resistance (b) Synchronous reactance +// (c) Short-circuit ratio +// Page 377 + +clc; +clear; +close; + +// Given data +Vdc=10.35; // DC voltage +Idc=52.80; // DC current +VOCph=240/sqrt(3); // Open-circuit phase voltage +ISCph=115.65; // Short-circuit phase current +P=50000; +V=240; // Supply voltage + +// (a) Equivalent armature resistance +Rdc=Vdc/Idc; // DC resistance +Rgamma=Rdc/2; +Ra=1.2*Rgamma; // Armature resistance + +// (b) Synchronous reactance +Zs= VOCph/ISCph; // Synchronous impedance/phase +Xs=sqrt(Zs^2-Ra^2); + +// (c) Short-circuit ratio +Sbase=P/3; // Power/phase +Vbase=V/sqrt(3); // Voltage/phase +Zbase=Vbase^2/Sbase; +Xpu=Xs/Zbase; // Per unit synchronous reactance +SCR=1/Xpu; // Short-circuit ratio + + +// Display result on command window +printf("\n Equivalent armature resistance = %0.4f Ohm ",Ra); +printf("\n Synchronous reactance = %0.4f Ohm ",Xs); +printf("\n Short-circuit ratio = %0.3f ",SCR); + diff --git a/3574/CH9/EX9.2/EX9_2.png b/3574/CH9/EX9.2/EX9_2.png new file mode 100644 index 000000000..219a86c2d Binary files /dev/null and b/3574/CH9/EX9.2/EX9_2.png differ diff --git a/3574/CH9/EX9.2/EX9_2.sce b/3574/CH9/EX9.2/EX9_2.sce new file mode 100644 index 000000000..02d615f88 --- /dev/null +++ b/3574/CH9/EX9.2/EX9_2.sce @@ -0,0 +1,23 @@ +// Example 9.2 +// Determine (a) Speed regulation (b) Governor drop +// Page 351 + +clc; +clear; +close; + +// Given data +fn1=61.2; // No-load frequency +frated=60; // Rated requency +deltaP=500; // Governor rated power +// (a) Speed regulation +GSR=(fn1-frated)/frated; + +// (b) Governor drop +deltaF=(fn1-frated); // Frequency difference +GD=deltaF/deltaP; + +// Display result on command window +printf("\n Speed regulation = %0.2f ",GSR); +printf("\n Governor drop = %0.5f Hz/kW ",GD); + diff --git a/3574/CH9/EX9.3/EX9_3.png b/3574/CH9/EX9.3/EX9_3.png new file mode 100644 index 000000000..06da73ec1 Binary files /dev/null and b/3574/CH9/EX9.3/EX9_3.png differ diff --git a/3574/CH9/EX9.3/EX9_3.sce b/3574/CH9/EX9.3/EX9_3.sce new file mode 100644 index 000000000..dfccb7b04 --- /dev/null +++ b/3574/CH9/EX9.3/EX9_3.sce @@ -0,0 +1,32 @@ +// Example 9.3 +// Determine (a) Frequency of generator A (b) Frequency of generator B +// (c) Frequency of bus +// Page 358 + +clc; +clear; +close; + +// Given data +GSR=0.020; // Governor speed regulation +Frated=60; // Rated frequency +deltaPa=100; // Change in load (200-100 =100 KW) +Prated=500; // Rated power of both generators + + +// (a) Frequency of generator A +deltaFa=(GSR*Frated*deltaPa)/Prated; // Change in frequency due to change in load +Fa=Frated+deltaFa; // Frequency of generator A + +// (b) Frequency of generator B +deltaFb=0.24; // Since both machines are identical +Fb=Frated-deltaFb; + +// (c) Frequency of bus +Fbus=Fb; // Bus frequency is frequency of generator B + +// Display result on command window +printf("\n Frequency of generator A = %0.2f Hz ",Fa); +printf("\n Frequency of generator B = %0.2f Hz ",Fb); +printf("\n Frequency of bus = %0.2f Hz ",Fbus); + diff --git a/3574/CH9/EX9.4/EX9_4.png b/3574/CH9/EX9.4/EX9_4.png new file mode 100644 index 000000000..1e0487052 Binary files /dev/null and b/3574/CH9/EX9.4/EX9_4.png differ diff --git a/3574/CH9/EX9.4/EX9_4.sce b/3574/CH9/EX9.4/EX9_4.sce new file mode 100644 index 000000000..03cbf6291 --- /dev/null +++ b/3574/CH9/EX9.4/EX9_4.sce @@ -0,0 +1,37 @@ +// Example 9.4 +// Determine (a) Operating frequency (b) Load carried by each machine +// Page 359 + +clc; +clear; +close; + +// Given data +GSR=0.0243; // Governor speed regulation +Frated=60; // Rated frequency +deltaPa=500; // Change in load for alternator A +Prateda=500; // Rated power of alternator A +deltaPb=400; // Change in load for alternator B +Pratedb=300; // Rated power of alternator B +Pch=100; // Change is power (500-400=100 KW)) +Pchmach=200; // Power difference (500-300=200 KW) + +// (a) Operating frequency +// From the curve in figure 9.17 +// GSR*Frated/Prated=deltaP/deltaP + +deltaF=(deltaPa-deltaPb)/548.697; // Change in frequency +Fbus=60.5-deltaF; + + +// (b) Load carried by each machine +deltaPa=(deltaF*Prateda)/(GSR*Frated); // Change in power for machine A +deltaPb=Pch-deltaPa; // Change in power for machine B +Pa=Pchmach+deltaPa; +Pb=Pchmach+deltaPb; + +// Display result on command window +printf("\n Operating frequency = %0.3f Hz ",Fbus); +printf("\n Load carried by machine A = %0.2f kW",Pa); +printf("\n Load carried by machine B = %0.2f kW",Pb); + diff --git a/3574/CH9/EX9.5/EX9_5.png b/3574/CH9/EX9.5/EX9_5.png new file mode 100644 index 000000000..7f57f90bf Binary files /dev/null and b/3574/CH9/EX9.5/EX9_5.png differ diff --git a/3574/CH9/EX9.5/EX9_5.sce b/3574/CH9/EX9.5/EX9_5.sce new file mode 100644 index 000000000..9864d5ff4 --- /dev/null +++ b/3574/CH9/EX9.5/EX9_5.sce @@ -0,0 +1,29 @@ +// Example 9.5 +// Determine (a) Bus frequency (b) Load on each machine +// Page 360 + +clc; +clear; +close; + +// Given data +Padd=720; // Additional load connected +GD=0.0008; // Governor droop +f=60.2; // Frequency of machine +Pbus=900; // Bus load + +// (a) Bus frequency +deltaPa=Padd/2; +deltaPb=deltaPa; // Since both machines have identical governor drops +deltaF=GD*deltaPa; // Change in frequency +Fbus=f-deltaF; + +// (b) Load on each machine +Pa=(2/3)*Pbus+deltaPa; // Load on machine A +Pb=(1/3)*Pbus+deltaPb; // Load on machine B + +// Display result on command window +printf("\n Bus frequency = %0.2f Hz ",Fbus); +printf("\n Load on machine A = %0.0f kW",Pa); +printf("\n Load on machine B = %0.0f kW",Pb); + diff --git a/3574/CH9/EX9.6/EX9_6.png b/3574/CH9/EX9.6/EX9_6.png new file mode 100644 index 000000000..c15480fb7 Binary files /dev/null and b/3574/CH9/EX9.6/EX9_6.png differ diff --git a/3574/CH9/EX9.6/EX9_6.sce b/3574/CH9/EX9.6/EX9_6.sce new file mode 100644 index 000000000..d2a20c23b --- /dev/null +++ b/3574/CH9/EX9.6/EX9_6.sce @@ -0,0 +1,42 @@ +// Example 9.6 +// Determine (a) System kilowatts (b) System frequency (c) kilowatt loads +// carried by each machine +// Page 361 + +clc; +clear; +close; + +// Given data +Pres=440; // Resistive load +PF=0.8; // Power factor +Pind=200; // Induction motor power +Palt=210; // Alternator bus load +deltaPa=70; // Change in load for machine A +f=60; // Frequency +deltaPb=70; // Change in load for machine B +deltaPc=70; // Change in load for machine C + +// (a) System kilowatts +deltaPbus=Pres+PF*Pind; // Increase in bus load +Psys=Palt+deltaPbus; + +// (b) System frequency +GDa=(60.2-f)/deltaPa; // Governor droop for machine A +GDb=(60.4-f)/deltaPb; // Governor droop for machine B +GDc=(60.6-f)/deltaPc; // Governor droop for machine C +// From the figure 9.18(b) +deltaF=600/(350+175+116.6667) ; +f2=f-deltaF; + +// (c) Kilowatt loads carried by each machine +Pa2=deltaPa+350*deltaF; +Pb2=deltaPb+175*deltaF; +Pc2=deltaPc+116.6667*deltaF; + +// Display result on command window +printf("\n System kilowatts = %0.0f kW ",Psys); +printf("\n System frequency = %0.2f Hz",f2); +printf("\n Kilowatt loads carried by machine A = %0.1f kW",Pa2); +printf("\n Kilowatt loads carried by machine B = %0.1f kW",Pb2); +printf("\n Kilowatt loads carried by machine C = %0.1f kW",Pc2); diff --git a/3574/CH9/EX9.7/EX9_7.png b/3574/CH9/EX9.7/EX9_7.png new file mode 100644 index 000000000..e00dd7abe Binary files /dev/null and b/3574/CH9/EX9.7/EX9_7.png differ diff --git a/3574/CH9/EX9.7/EX9_7.sce b/3574/CH9/EX9.7/EX9_7.sce new file mode 100644 index 000000000..3c811616d --- /dev/null +++ b/3574/CH9/EX9.7/EX9_7.sce @@ -0,0 +1,34 @@ +// Example 9.7 +// Determine (a) Active and reactive components of the bus load (b) If the +// power factor of generator A is 0.94 lagging, determine the reactive power +// supplied by each machine. +// Page 366 + +clc; +clear; +close; + +// Given data +Pbuspower=500; // Power supplied +Pind=200; // Induction motor power +PF=0.852; // Percent power factor +NA=2; // Number of alternators +LPF=0.94; // Lagging power factor + +// (a) Active and reactive components of the bus load +Pbus=Pbuspower+Pind*PF; // Active component of the bus load +ThetaMot=acosd(PF); // Power angle of motor +Qbus=Pind*sind(ThetaMot); // Reactive component the bus load + +// (b) Reactive power supplied by each machine +Pa=Pbus/NA; // Alternator A power +ThetaA=acosd(LPF); // Alternator A angle +Qa=tand(ThetaA)*Pa; // Reactive power supplied by machine A +Qb=Qbus-Qa; // Reactive power supplied by machine B + + +// Display result on command window +printf("\n Active component of the bus load = %0.2f kW ",Pbus); +printf("\n Reactive component of the bus load = %0.1f kvar",Qbus); +printf("\n Reactive power supplied by machine A = %0.1f kvar",Qa); +printf("\n Reactive power supplied by machine B = %0.1f kvar",Qb); diff --git a/3574/CH9/EX9.8/EX9_8.png b/3574/CH9/EX9.8/EX9_8.png new file mode 100644 index 000000000..72bdb8964 Binary files /dev/null and b/3574/CH9/EX9.8/EX9_8.png differ diff --git a/3574/CH9/EX9.8/EX9_8.sce b/3574/CH9/EX9.8/EX9_8.sce new file mode 100644 index 000000000..5906bbf8d --- /dev/null +++ b/3574/CH9/EX9.8/EX9_8.sce @@ -0,0 +1,30 @@ +// Example 9.8 +// Computation of per-unit impedance of a generator +// Page 368 + +clc; +clear; +close; + +// Given data +P=100000; // Power of synchronous generator +V=480; // Voltage of synchronous generator +Ra=0.0800; // Resistive component +Xs=2.3; // Reactive component + +// Computation of per-unit impedance of a generator +Sbase=P/3; // Rated apparent power per phase +Vbase=V/sqrt(3); // Rated voltage per phase +Zbase=Vbase^2/Sbase; // Rated impedance +Rpu=Ra/Zbase; // Per unit resistance +Xpu=Xs/Zbase; // Per unit reactance + +Zpu=Rpu+%i*Xpu; // Per unit impedance + +// Complex to Polar form... +Zpu_Mag=sqrt(real(Zpu)^2+imag(Zpu)^2); // Magnitude part +Zpu_Ang = atan(imag(Zpu),real(Zpu))*180/%pi; // Angle part
 + +// Display result on command window +printf("\n Per-unit impedance magnitude = %0.4f Ohm ",Zpu_Mag); +printf("\n Per-unit impedance angle = %0.2f deg ",Zpu_Ang); diff --git a/3574/CH9/EX9.9/EX9_9.png b/3574/CH9/EX9.9/EX9_9.png new file mode 100644 index 000000000..a837c7d8d Binary files /dev/null and b/3574/CH9/EX9.9/EX9_9.png differ diff --git a/3574/CH9/EX9.9/EX9_9.sce b/3574/CH9/EX9.9/EX9_9.sce new file mode 100644 index 000000000..de0d1fd19 --- /dev/null +++ b/3574/CH9/EX9.9/EX9_9.sce @@ -0,0 +1,68 @@ +// Example 9.9 +// Determine (a) Excitation voltage (b) Power angle (c) No load voltage, +// assuming the field current is not changed (d) Voltage regulation (e) No load +// voltage if the field current is reduced to 80% of its value at rated load. +// Page 369 + +clc; +clear; +close; + +// Given data +V=4800; // Voltage of synchronous generator +PF=0.900; // Lagging power factor +S_Mag=1000000/3; +Xa_Mag=13.80; // Synchronous reactance +Xa_Ang=90; +Vt_Ang=0; + +// (a) Excitation voltage +Vt=V/sqrt(3); +Theta=acosd(PF); // Angle +Ia_Magstar=S_Mag/Vt; // Magnitude of curent +Ia_Angstar=Theta-0; // Angle of current +Ia_Mag=Ia_Magstar; +Ia_Ang=-Ia_Angstar; + +// Ef=Vt+Ia*j*Xa +// First compute Ia*Xa +IaXa_Mag=Ia_Mag*Xa_Mag; +IaXa_Ang=Ia_Ang+Xa_Ang; +// Polar to Complex form for IaXa +IaXa_R=IaXa_Mag*cos(-IaXa_Ang*%pi/180); // Real part of complex number +IaXa_I=IaXa_Mag*sin(IaXa_Ang*%pi/180); // Imaginary part of complex number +// Vt term in polar form +Vt_Mag=Vt; +Vt_Ang=Vt_Ang; +// Polar to Complex form for Vt +Vt_R=Vt_Mag*cos(-Vt_Ang*%pi/180); // Real part of complex number +Vt_I=Vt_Mag*sin(Vt_Ang*%pi/180); // Imaginary part of complex number +// Ef in complex form +Ef_R=IaXa_R+Vt_R; +Ef_I=IaXa_I+Vt_I; +Ef=Ef_R+%i*Ef_I; +// Complex to Polar form for Ef +Ef_Mag=sqrt(real(Ef)^2+imag(Ef)^2); // Magnitude part +Ef_Ang= atan(imag(Ef),real(Ef))*180/%pi; // Angle part
 + +// (b) Power angle +PA=Ef_Ang; + +// (c) No load voltage, assuming the field current is not changed +// From figure 9.23 (b) +VolAxis=Vt_Mag/30; // The scale at the given voltage axis +Ef_loc=Ef_Mag/VolAxis; // Location of Ef voltage +Vnl=33.4*VolAxis; // No load voltage + +// (d) Voltage regulation +VR=(Vnl-Vt)/Vt*100; + +// (e) No load voltage if the field current is reduced to 80% +Vnlnew=31*VolAxis; + +// Display result on command window +printf("\n Excitation voltage = %0.0f V ",Ef_Mag); +printf("\n Power angle = %0.1f deg ",PA); +printf("\n No load voltage = %0.0f V ",Vnl); +printf("\n Voltage regulation = %0.0f Percent ",VR); +printf("\n No load voltage when field current is reduced to 80 percent = %0.0f V ",Vnlnew); -- cgit