1 files changed, 33 insertions, 0 deletions
diff --git a/2372/CH2/EX2.4/ex4.sce b/2372/CH2/EX2.4/ex4.sce
new file mode 100644
index 000000000..a70bff9fb
--- /dev/null
+++ b/2372/CH2/EX2.4/ex4.sce
@@ -0,0 +1,33 @@
+clc;
+clear;
+v=1400;//rms voltage
+f=60;//frequency 
+kva1=125; pf1=0.28; //inductive load and lagging power factor
+kw2=10; kvar2=-40; //active and reactive power of a capacitive load
+kw3=15;//resistive load
+theta1=acos(pf1);
+s1=complex(125*cos(theta1),125*sin(theta1));
+s2=complex(kw2,kvar2);
+s3=complex(kw3,0);
+s=s1+s2+s3;//total apparent power
+mprintf("total apparent power,s=%d kW+%d kvar=%d angle%4.2f kVA \n",real(s),imag(s),abs(s),atan(imag(s),real(s))*180/%pi);
+i=s'*1000/v';//total current
+mprintf("total current,i=%4.2f angle %4.2f A\n",abs(i),atan(imag(i),real(i))*180/%pi);
+thetai=atan(imag(i),real(i));
+pf=cos(thetai);//lagging power factor
+mprintf("power factor,PF= %2.1f lagging\n",pf);
+p=real(s);//total active power
+q=imag(s);//total reactive power
+pfnew=0.8;//required power factor
+mprintf("required pf,pfnew=%2.1f lagging\n",pfnew);
+thetanew=acos(pfnew);
+qnew=p*tan(thetanew);
+qc=q-qnew;//capacitor kVar required
+mprintf("required capacitor kvar,qc=%d kvar\n",qc)
+xc=v*v/%i/qc/1000;
+c=10^6/(2*%pi*f*abs(xc));
+mprintf("capacitance,c=%4.2f uF\n",c);
+snew=complex(p,qnew);
+inew=snew'*1000/v';
+mprintf("new current, inew=%4.2f angle %4.2f A\n",abs(inew),atan(imag(inew),real(inew))*180/%pi);
+mprintf("note the reduction in supply current from 71.43 A to 53.57 A\n");