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{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 02 : Capacitance Of Transmission Lines"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.1, Page No 75"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#initialisation of variables\n",
"D = 20.0 #in ft\n",
"f = 60.0 #in Hz\n",
"\n",
"#From Table A.1 and A.3\n",
"d = 0.642 \t\t\t#in inches\n",
"X_a = 0.1074e6 \t\t#in ohm-mi\n",
"X_d = 0.0889e6 \t\t#in ohm-mi\n",
"\n",
"#finding radius\n",
"r = d/(2*12) \t\t#divided by 12 convert in to ft\n",
"\n",
"#Calculations\n",
"print('Calculations using conductor spacing and radius')\n",
"X_c = 1.779 * math.log(D/r)/f\n",
"B_c = 1 / X_c\n",
"print(\" Capactive reatance = %.4fe6 ohm mi to neutral \" %X_c)\n",
"print(\" Capactive susceptance = %.4fe-6 mho/mi to neutral \" %B_c)\n",
"\n",
"#calculations using capacitive reactance at 1-ft spacing and spacing factor\n",
"print('Calculations using capacitive reactance at 1-ft spacing and spacing factor')\n",
"X_c1 = X_a + X_d\n",
"print(\" Capactive reatance = %.4fe6 ohm mi per conductor \" %(X_c1/10**6))\n",
"X_c11 = 2 * X_c1\n",
"B_c1 = 1 / X_c11\n",
"\n",
"#Results\n",
"print(\" Line-to-line capactive reatance = %.4fe6 ohm mi \" %(X_c11/10**6))\n",
"print(\" Line-to-line capactive susceptance = %.4fe-6 mho mi \" %(B_c1*10**6))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Calculations using conductor spacing and radius\n",
" Capactive reatance = 0.1962e6 ohm mi to neutral \n",
" Capactive susceptance = 5.0970e-6 mho/mi to neutral \n",
"Calculations using capacitive reactance at 1-ft spacing and spacing factor\n",
" Capactive reatance = 0.1963e6 ohm mi per conductor \n",
" Line-to-line capactive reatance = 0.3926e6 ohm mi \n",
" Line-to-line capactive susceptance = 2.5471e-6 mho mi \n"
]
}
],
"prompt_number": 14
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.2, Page No 80"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#initialisation of variables\n",
"D_12 = 20.0\t\t\t#in ft\n",
"D_23 = D_12\n",
"D_31 = 38.0\t\t\t#in ft\n",
"f = 60.0\t\t\t#in Hz\n",
"V = 220e3\t\t\t#in volts\n",
"l = 175\t\t\t\t#in mi\n",
"k = 8.85e-12\t\t#permittivity in F/m\n",
"#From tables A.1 and A.3\n",
"d = 1.108#in inches\n",
"X_a1 = 0.0912e6#in ohm mi\n",
"X_d1 = 0.0952e6#in ohm mi\n",
"\n",
"#Calculations\n",
"r = d / ( 2 * 12)#division by 12 to convert in to ft\n",
"D_eq = (D_12*D_23*D_31)**(1.0/3)\n",
"C_n = (2*math.pi*k)/math.log(D_eq/r)\n",
"X_c = 1.0/(2*math.pi*f*C_n*1609)\t\t#division by 1609 to convert to ohm mi\n",
"\n",
"print(\" Capacitance = %.4fe-12 F/m \" %(C_n*1e12))\n",
"print(\" Capacitive reactance = %.4fe6 ohm mi \" %(X_c/1e6))\n",
"\n",
"#Calculations From tables\n",
"X_c1 = X_a1 + X_d1\n",
"print('Using capacitive reactance at 1-ft spacing and spacing factor')\n",
"print(\" Capacitive reactance = %.4fe6 ohm mi \" %(X_c1/1e6))\n",
"X_c_l = X_c1/l\t\t\t#Capacitive reactance for 175mi\n",
"I_chg = 2*math.pi*f*V*C_n*1609/math.sqrt(3.0)\n",
"I_chg_l = I_chg * l\n",
"Q =math.sqrt(3)*V*I_chg_l\n",
"\n",
"\n",
"#Results\n",
"print('For a lenght of 175mi')\n",
"print(\" Capacitive reactance = %.4f ohm to neutral \" %X_c_l)\n",
"print(\" Charging current per mile = %.3f A/mi \" %I_chg)\n",
"print('For a lenght of 175mi')\n",
"print(\" Charging current = %.0f A \" %I_chg_l)\n",
"print(\" Total charging megavolt-amperes = %.1f Mvar \" %(Q/1e6))\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Capacitance = 8.8472e-12 F/m \n",
" Capacitive reactance = 0.1863e6 ohm mi \n",
"Using capacitive reactance at 1-ft spacing and spacing factor\n",
" Capacitive reactance = 0.1864e6 ohm mi \n",
"For a lenght of 175mi\n",
" Capacitive reactance = 1065.1429 ohm to neutral \n",
" Charging current per mile = 0.682 A/mi \n",
"For a lenght of 175mi\n",
" Charging current = 119 A \n",
" Total charging megavolt-amperes = 45.5 Mvar \n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.3, Page No 85"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#initialisation of variables\n",
"d = 0.45 #in m\n",
"k = 8.85e-12 #in F/m\n",
"D_ab = 8 #in m\n",
"D_bc = D_ab\n",
"D_ca = 16 #in m\n",
"f = 60 #in Hz\n",
"\n",
"#From tables\n",
"D = 1.382 #in inches\n",
"\n",
"#Calculations\n",
"r = D*0.3048/(2.0*12) #divison by 12 to convert in to ft\n",
" #multiplication by 0.3048 to convert ft to m\n",
"D_b_sC = math.sqrt( r * d)\n",
"D_eq = (D_ab * D_bc * D_ca)**(1/3)\n",
"C_m = 2* math.pi*k/math.log(D_eq / D_b_sC)\n",
"X_c = 1e-3/(2*math.pi*f*C_m) #1e-3 #to convert m to km\n",
"\n",
"#Results\n",
"print(\" Capacitance = %.3fe-12 F/m \" %(C_m * 1e12))\n",
"print(\" Capacitive reactance = %.4fe6 ohm km per phase to neutral\" %(X_c/1e6))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Capacitance = 22.972e-12 F/m \n",
" Capacitive reactance = 0.1155e6 ohm km per phase to neutral\n"
]
}
],
"prompt_number": 16
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.4 Page No 85"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#initialisation of variables\n",
"f = 60.0\t\t#in Hz\n",
"k = 8.85e-12\t#in F/m\n",
"D_eq = 16.1\t\t#in ft\n",
"D_a_a1 = 26.9\n",
"D_b_b1 = 21.0\n",
"D_c_c1 = D_a_a1 #in ft\n",
"\n",
"#From Table A.1\n",
"d = 0.680#in inches\n",
"\n",
"#calculations\n",
"r = d /(2*12)\n",
"D_p_sC = (math.sqrt(D_a_a1 * r) * math.sqrt(D_b_b1 * r) * math.sqrt(D_c_c1 * r))**(1.0/3)\n",
"C_n = 2 * math.pi * k / math.log(D_eq / D_p_sC)\n",
"B_c = 2 * math.pi * f * C_n * 1609.0\t#1609 to convert from m to mi\n",
"\n",
"#Results\n",
"print(\"printprint Capacitance = %.3fe-12 F/m printprint\" %(C_n*1e12))\n",
"print(\"printprint Capacitive susceptance = %.2fe-6 mho per mi per phase to neutral\" %(B_c*1e6))"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"printprint Capacitance = 18.812e-12 F/m printprint\n",
"printprint Capacitive susceptance = 11.41e-6 mho per mi per phase to neutral\n"
]
}
],
"prompt_number": 17
}
],
"metadata": {}
}
]
}
|
