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 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Ch-12, Parallel Operation of alternators"
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "example 12.1 Page 243"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "p=4000  #given kva of alternator\n",
      "fnl1=50  #frequency on no load\n",
      "fl1=47.5 #frequency on load\n",
      "fnl2=50 #frequency on no load on second alternator\n",
      "fl2=48  #frequency on load on second alternator\n",
      "l=6000 #load given two to alternator\n",
      "df1=fnl1-fl1  #change in 1 alternator frequency\n",
      "df2=fnl2-fl2  #change in 2 alternator frequency\n",
      "l1=df2*(l)/(df2+df1)  #load on 1 alternator\n",
      "print 'a'\n",
      "l2=l-l1\n",
      "print \" load on 1 alternator %.2fkW \\n load on 2 alternator %.2fkW\"%(l1,l2)\n",
      "ml1=df2*p/df1   #load on 1 machine when machine 2 on full load\n",
      "ll=ml1+p  \n",
      "print 'b'\n",
      "print \" load supplied by machine 1 with full load on machine2 %dkW \\n total load is %dkW\"%(ml1,l1) "
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "a\n",
        " load on 1 alternator 2666.67kW \n",
        " load on 2 alternator 3333.33kW\n",
        "b\n",
        " load supplied by machine 1 with full load on machine2 3200kW \n",
        " total load is 2666kW\n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "example 12.2 page 243"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from math import sqrt, atan, acos, pi, sin\n",
      "l1=3000 #load on 1 machine\n",
      "pf1=0.8  #pf on 1 machine\n",
      "i2=150  #current on  2 machine\n",
      "z1=0.4+12*1J  #synchronour impedence\n",
      "z2=0.5+10*1J\n",
      "vt=6.6  #terminal voltage\n",
      "al=l1/2  #active load on each machine\n",
      "cosdb=al/(vt*i2*sqrt(3)) #cos db\n",
      "db=acos(cosdb)*180/pi  #angle in digree\n",
      "ib=i2*complex(cosdb,-sin(db*pi/180))  #current in complex number\n",
      "it=l1/(vt*pf1*sqrt(3))  #total current\n",
      "itc=complex(it*pf1,-it*sin(acos(pf1)))  #total current in complex\n",
      "ia=itc-ib  \n",
      "pfa=atan(ia.imag/ia.real)  #pf of current a\n",
      "ea=(vt/sqrt(3))+ia*(z1)/1000  #voltage a\n",
      "pha=atan(ea.imag/ea.real)*180/pi  #phase angle of unit a\n",
      "print \"induced emf of a machine a %.2f+%.2fi =%fkV per phase\"%(ea.real,ea.imag,abs(ea))\n",
      "eb=(vt/sqrt(3))+ib*(z2)/1000  #voltage b\n",
      "phb=atan(eb.imag/eb.real)*180/pi  #phase angle of unit b\n",
      "print \"\\ninduced emf of a machine b %.2f+%.2fi =%fkV per phase\"%(eb.real,eb.imag,abs(eb))"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "induced emf of a machine a 5.35+1.52i =5.565708kV per phase\n",
        "\n",
        "induced emf of a machine b 4.60+1.28i =4.776461kV per phase\n"
       ]
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "example 12.3 Page 244"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from math import cos\n",
      "e1=3000 ;ph1=20 ;e2=2900; ph2=0 #given induced emf of two machines\n",
      "z1=2+20*1J ;z2=2.5+30*1J #impedence of two synchronous machine\n",
      "zl=10+4*1J #load impedence\n",
      "e11=e1*(cos(ph1*pi/180)+sin(ph1*pi/180)*1J)\n",
      "e22=e2*(cos(ph2*pi/180)+sin(ph2*pi/180)*1J)\n",
      "Is=(e11-e22)*zl/(z1*z2+(z1+z2)*zl)\n",
      "print \"current is %.2f%.2fiA =%.2fA\"%((Is).real,(Is).imag,abs(Is))"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "current is 10.37-4.56iA =11.33A\n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "example 12.4 Page 244"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "z=10+5*1J  #load\n",
      "e1=250 ;e2=250 #emf of generator\n",
      "z1=2*1J; z2=2*1J #synchronous impedence\n",
      "v=(e1*z2+z1*e2)/((z1*z2/z)+z1+z2) \n",
      "vph=atan(v.imag/v.real)*180/pi #substitution the value in equation 12.10\n",
      "i1=(z2*e1+(e1-e2)*z)/(z1*z2+(z1+z2)*z); iph=atan((i1).imag/(i1).real)*180/pi #substitution the value in equation 12.7\n",
      "pf1=cos(pi/180*(vph-iph))\n",
      "pd=v*i1*pf1\n",
      "z=10+5*1J  #load\n",
      "e1=250 ;e2=250 #emf of generator\n",
      "z1=2*1J; z2=2*1J #synchronous impedence\n",
      "v=(e1*z2+z1*e2)/((z1*z2/z)+z1+z2) \n",
      "vph=atan(v.imag/v.real)*180/pi #substitution the value in equation 12.10\n",
      "i1=(z2*e1+(e1-e2)*z)/(z1*z2+(z1+z2)*z) \n",
      "iph=atan(i1.imag/i1.real)*180/pi #substitution the value in equation 12.7\n",
      "pf1=cos(pi/180*(vph-iph))\n",
      "pd=v*i1*pf1\n",
      "print \"terminal voltage %.2fV \\ncurrent supplied by each %.2fA \\npower factor of each %.3f lagging \\npower delivered by each %.4fKW\"%(abs(v),abs(i1),abs(pf1),abs(pd))"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "terminal voltage 239.68V \n",
        "current supplied by each 10.72A \n",
        "power factor of each 0.894 lagging \n",
        "power delivered by each 2297.7941KW\n"
       ]
      }
     ],
     "prompt_number": 9
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "example 12.5 Page 247"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "po=5 #mva rating\n",
      "v=10 #voltage in kv\n",
      "n=1500 ;ns=n/60 #speed\n",
      "f=50 #freaquency\n",
      "pfb=0.8#power factor in b\n",
      "x=0.2*1J #reactance of machine\n",
      "md=0.5 #machanical displacement\n",
      "#no load\n",
      "v=1 ;e=1 \n",
      "p=4\n",
      "spu=v*e/abs(x); sp=spu*po*1000 ;mt=(pi*p)/(180*2)\n",
      "spm=sp*mt #synchronous power in per mech.deree\n",
      "st=spm*md*1000/(2*ns*pi)\n",
      "print '(a)'\n",
      "print \" synchronous power %dkW \\n synchronous torque for %.1f displacement %dN-M\"%(spm,md,st)\n",
      "print '(b) full load'\n",
      "ee=e+x*(pfb-sin(acos(pfb))*1J)\n",
      "spb=v*abs(ee)*cos(atan(ee.imag/ee.real))/abs(x)  #synchronous power \n",
      "sppm=spb*po*1000*mt #synchronous power per mech.degree\n",
      "stp=sppm*md*1000/(2*pi*ns)#synchrounous torque under load\n",
      "print \" synchronous power %dkW \\n synchronous torque for %.1f displacement %dN-M\"%(sppm,md,stp)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "(a)\n",
        " synchronous power 872kW \n",
        " synchronous torque for 0.5 displacement 2777N-M\n",
        "(b) full load\n",
        " synchronous power 977kW \n",
        " synchronous torque for 0.5 displacement 3111N-M\n"
       ]
      }
     ],
     "prompt_number": 10
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "example 12.6 page 248"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "po=2*10**6 ;p=8 ;n=750; v=6000 ;x=6*1J ;pf=0.8 #given \n",
      "i=po/(v*sqrt(3))\n",
      "e=(v/sqrt(3))+i*x*(pf-sin(acos(pf))*1J)\n",
      "mt=p*pi/(2*180)\n",
      "cs=cos(atan(e.imag/e.real))\n",
      "ps=abs(e)*v*sqrt(3)*cs*mt/(1000*abs(x))\n",
      "ns=n/60\n",
      "ts=ps*1000/(2*pi*ns)\n",
      "print \" synchronous power %.1fkW per mech.degree \\n synchrounous torque %dN-m\"%(ps,ts)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " synchronous power 502.7kW per mech.degree \n",
        " synchrounous torque 6666N-m\n"
       ]
      }
     ],
     "prompt_number": 11
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "example 12.7 page 248"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "i=100 ;pf=-0.8 ;v=11*1000 ;x=4*1J ;ds=10; pfc=-0.8 #given,currents,power factor,voltage,reactance,delta w.r.t steem supply,pf of alternator\n",
      "e=(v/sqrt(3))+(i*x*(pf-sin(acos(pf))*1J))\n",
      "print 'a'\n",
      "ph=atan(e.imag/e.real)*180/pi\n",
      "print \" open circuit emf %dvolts per phase and %.2f degree\"%(abs(e),ph)\n",
      "d=ds-ph\n",
      "eee=round(abs(e)/100)*100\n",
      "ic=round(abs(eee)*sin(d*pi/180)/abs(x))\n",
      "iis=(eee**2-(abs(x)*ic)**2)**(0.5)\n",
      "Is=(iis-v/sqrt(3))/abs(x)\n",
      "tad=Is/ic\n",
      "d=atan(tad)*180/pi\n",
      "ii=ic/cos(d*pi/180)\n",
      "pff=cos(d*pi/180)\n",
      "print 'b.'\n",
      "print \" current %.1fA \\n power factor %.3f\"%(ii,pff)\n",
      "print 'c.'\n",
      "ia=ii*pff/abs(pfc)\n",
      "print \"current %.2fA\"%(ia)\n",
      "\n",
      "ia=ii*pff/abs(pfc)\n",
      "print \"current %.2fA\"%(ia)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "a\n",
        " open circuit emf 6598volts per phase and -2.78 degree\n",
        "b.\n",
        " current 365.6A \n",
        " power factor 0.998\n",
        "c.\n",
        "current 456.25A\n",
        "current 456.25A\n"
       ]
      }
     ],
     "prompt_number": 12
    }
   ],
   "metadata": {}
  }
 ]
}