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diff --git a/Electrical_Power_Systems_by_C_L_Wadhwa/14-PROTECTIVE_RELAYS.ipynb b/Electrical_Power_Systems_by_C_L_Wadhwa/14-PROTECTIVE_RELAYS.ipynb new file mode 100644 index 0000000..e4bb89c --- /dev/null +++ b/Electrical_Power_Systems_by_C_L_Wadhwa/14-PROTECTIVE_RELAYS.ipynb @@ -0,0 +1,342 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 14: PROTECTIVE RELAYS" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.10: To_determine_the_kneepoint_voltage_and_cross_section_of_core.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine the kneepoint voltage and cross section of core\n", +"clear \n", +"clc;\n", +"Ic=5*.25;// operating current(amp)\n", +"Vsec=5/1.25;// secondary voltage(V)\n", +"Bm=1.4;\n", +"f=50;\n", +"N=50;\n", +"V=15*Vsec;\n", +"A=60/(4.44*Bm*f*N);\n", +"mprintf(' the knee point must be slightly higher than =%.3f V\n',V);\n", +"mprintf('area of cross section=%.6f m_2\n',A);" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.11: To_determine_the_VA_output_of_CT.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine the VA output of CT .\n", +"clear \n", +"clc;\n", +"o.p=5*5*(.1+.1) +5;\n", +"mprintf(' VA output of CT =%.0f VA\n ',o.p);" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.1: To_determine_the_time_of_operation_of_relay.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine the time of operation of relay .\n", +"clear\n", +"clc;\n", +"If=4000;// fault current \n", +"I=5*1.25;// operating current of relay \n", +"CT=400/5;// CT ratio\n", +"PSM=If/(I*CT);// plug setting multiplier\n", +"mprintf('PSM=%.3f\n',PSM);\n", +"mprintf('operating time for PSM=8 is 3.2sec.\n');\n", +"mprintf('actual operating time = 1.92 sec.');" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.2: To_determine_the_phase_shifting_network_to_be_used.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine the phase shifting network to be used.\n", +"clear\n", +"clc;\n", +"Z=1000*(cosd(60) + %i*sind(60));//impedence\n", +"X=tand(50)*1000*cosd(60);\n", +"Xl=1000*sind(60);\n", +"Xc=Xl-X;\n", +"C=1000000/(314*Xc);\n", +"//Answers don't match due to difference in rounding off of digits\n", +"disp(X,'X=');\n", +"disp(Xc,'Xc=');\n", +"disp(C,'C(micro farads)=');" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.3: To_provide_time_current_grading.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//To provide time current grading .\n", +"clear \n", +"clc;\n", +"Isec1=4000/40;// secondary current(amps)\n", +"PSM=100/5;// PSM if 100% setting is used\n", +"Isec2=4000/40;\n", +"PSM2=100/6.25;//PSM if setting used is 125%\n", +"TMSb=.72/2.5;\n", +"PSM1=5000/(6.25*40);\n", +"to=2.2;\n", +"tb=to*TMSb;\n", +"PSMa=5000/(6.25*80);\n", +"TMS=1.138/3;\n", +"PSMa1=6000/(6.25*80);\n", +"ta=(2.6*.379);\n", +"mprintf('Actual operating time of realy at b=%.3f sec. \n',tb);\n", +"mprintf('Actual operating time of realy at a=%.3f sec. \n',ta);" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.4: EX14_4.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine the proportion of the winding which remains unprotected against earth fault.\n", +"clear\n", +"clc;\n", +"Vph=6600/(sqrt(3));\n", +"Ifull=5000/(sqrt(3)*6.6);\n", +"Ib=Ifull*.25;\n", +"x=Ib*800/Vph;\n", +"mprintf('percent of the winding remains unprotected=%.2f \n',x);" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.5: EX14_5.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine (i) % winding which remains unprotected (ii)min. value of earthing resistance required to protect 80% of winding \n", +"clear \n", +"clc;\n", +"Iph=10000/sqrt(3);// phase voltage of alternator(V)\n", +"x=1.8*100*10*1000/(5*Iph);\n", +"mprintf('(i) percent winding which remains unprotected=%.2f \n',x);\n", +"Ip=Iph*.2;\n", +"R=1.8*1000/(5*Ip);\n", +"mprintf('(ii)minimum value of earthing resistance required to protect 80 percent of winding =%.4f ohms \n',R)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.6: To_determine_whether_relay_will_operate_or_not.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//To determine whether relay will operate or not.\n", +"clear \n", +"clc;\n", +"Ic=360-320;// the difference current (amp)\n", +"Io=40*5/400;\n", +"Avg=(360+320)/2;// average sum of two currents\n", +"Iavg=340*5/400;\n", +"Ioc=.1*Iavg + .2;\n", +"mprintf('operating current=%.3f amp. \n',Ioc);\n", +"mprintf('since current through operating coil is %.3f amp. \n ',Io);\n", +"mprintf('therefore Relay will not operate ');" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.7: To_determine_the_ratio_of_CT_on_HV_side.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine the ratio of CT on HV side\n", +"clear\n", +"clc;\n", +"Il=400*6.6/33;// line current on star side of PT(amps)\n", +"Ic=5/sqrt(3);// current in CT secondary \n", +"mprintf(' the CT ratio on HT will be %d : %.3f',Il,Ic);" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.8: To_determine_the_number_of_turns_each_current_transformer_should_have.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// To determine the number of turns each current transformer should have .\n", +"clear \n", +"clc;\n", +"Il=10000/((sqrt(3))*132);\n", +"ILV=10000/((sqrt(3))*6.6);\n", +"a=5/sqrt(3);\n", +"mprintf('ratio of CT on LV side is %.3f : %.3f\n',ILV,a);\n", +"mprintf('ratio of CT on HT side is %.3f : %d',Il,5);" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 14.9: To_determine_the_R1_R2_and_C_also_The_potential_across_relays.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"//To determine the R1, R2 and C. also The potential across relays\n", +"clear \n", +"clc;\n", +"Vs=110;\n", +"I=1;\n", +"R2=Vs/((3-%i*sqrt(3))*I);\n", +"c=abs(R2);\n", +"mprintf('R2=%.2f ohms\n',c);\n", +"R1=2*c;\n", +"d=abs(R1);\n", +"C=(10^6)/(.866*d*314);\n", +"mprintf('R1=%.2f ohms\n',R1);\n", +"mprintf('C=%.1f micro farads\n',C);\n", +"Vt=d*(-.5 - %i*.866) + (c - %i*55 );\n", +"disp(Vt,' Voltage across the terminals of the relay will be (V)=');" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} |