Elect Notes

EMP Group of Companies Companies (PVT) LTD

Industrial Training Report

ACKNOWLEDGEMENT

Firstly, I am grateful to Dr. Nayana Alagiyawanna, Dean, Faculty of Engineering and Dr. Priyankara, Director, Engineering Educational Center, Faculty of Engineering, University of u!una. Also I take t!is o""ortunity to e#tend my gratitude to National A""r A""ren enti tice ce and and Indu Indust stri rial al $rai $raini ning ng Aut! Aut!or orit ityy %NAI %NAI$A $A&& for for maki making ng neces necessa sary ry arrangements to "rovide me a valua'le training "eriod. Also I am so Inde'ted to (r. C!andranandana Diyunuge, C!airman of E(P )rou" of Com"anies %P*$& +$D  (r. $. -ures! umara, (anaging Director of E(P )rou" of Com"anies %P*$& +$D for "roviding us all t!e facilities in order to !ave a valua'le training. Ne#t, my sincere gratitude is e#tended to (r. avi u"asing!e, )eneral (anager of E(P )rou" of Com"anies %P*$& +$D for e#tending us !is kind co/ o"eration. I take t!is o""ortunity to e#tend my "rofound "rofound t!anks to t!e Director 0oard of E(P )rou" of Com"anies %P*$& +$D. And Also I am so inde'ted to (r. $!usit!a )unasekara, 1ead of Electrical  Assem'ly -ection, for dedicating !is valua'le time on 'e!alf of our own goodness  for "roviding us a faculty of knowledge. Ne#t I am t!ankful to all t!e em"loyees of electrical  assem'ly section for giving us t!eir kind co/o"eration. I take t!is o""ortunity to e#"ress my "rofuse t!anks to (r. Indika De -ilva, Director of EP+, for giving us a !uge knowledge on "ro2ect !andling. And also I3m so t!ankful to all t!e staff of EP+ for e#tending t!eir friendly !ands towards us. And finally I e#tend my regards to all t!e em"loyees of E(P grou" for all t!e su""orts given to !ave a valua'le training. $!ank you4 5i2eweera D.A.P. U6E678896:;< Faculty of Engineering, University of u!una. Facult of Engineering! "ni#ersit of Ru$una%

:



PREFACE

$!is re"ort on industrial training "re"ared 'y myself was done so not only as an e#ercise e#ercise to fulfill fulfill a "art of t!e training training re=uirements re=uirements set out 'y NAI$A, 'ut also as a testimony testimony on t!e actual industri industrial al training training I !ad. 1ere'y, 1ere'y, a detailed account account of my training "rogrammed at E(P )rou" of Com"anies %P*$& +$D is included. $!e idea 'e!ind t!is com"ilation is t!at anyone going t!roug! t!is re"ort s!ould get a com"re!ensive understanding of all tec!nical as"ects of my training. In making t!is a reality, I tried my 'est to kee" to t!e guidelines sti"ulated 'y NAI$A. $!is is succeeded 'y my own training e#"erience, w!ic! is detailed to t!e most "ossi'le e#tent. $!is re"ort contains t!e entire e#"erience and knowledge I3ve ac!ieved from E(P )rou". $!e first c!a"ter introduces t!e com"any overview w!ere as t!e second and t!ird c!a"ters focus on switc! gears  "rotective devices. Ne#t two c!a"ters are used to descri'e t!e knowledge of ca'les  "anel 'oards. I finally !o"e t!at t!is !um'le and !onest effort of mine will meet t!e e#"ectations of t!e University training engineer.

Facult of Engineering! "ni#ersit of Ru$una%

7



PREFACE

$!is re"ort on industrial training "re"ared 'y myself was done so not only as an e#ercise e#ercise to fulfill fulfill a "art of t!e training training re=uirements re=uirements set out 'y NAI$A, 'ut also as a testimony testimony on t!e actual industri industrial al training training I !ad. 1ere'y, 1ere'y, a detailed account account of my training "rogrammed at E(P )rou" of Com"anies %P*$& +$D is included. $!e idea 'e!ind t!is com"ilation is t!at anyone going t!roug! t!is re"ort s!ould get a com"re!ensive understanding of all tec!nical as"ects of my training. In making t!is a reality, I tried my 'est to kee" to t!e guidelines sti"ulated 'y NAI$A. $!is is succeeded 'y my own training e#"erience, w!ic! is detailed to t!e most "ossi'le e#tent. $!is re"ort contains t!e entire e#"erience and knowledge I3ve ac!ieved from E(P )rou". $!e first c!a"ter introduces t!e com"any overview w!ere as t!e second and t!ird c!a"ters focus on switc! gears  "rotective devices. Ne#t two c!a"ters are used to descri'e t!e knowledge of ca'les  "anel 'oards. I finally !o"e t!at t!is !um'le and !onest effort of mine will meet t!e e#"ectations of t!e University training engineer.


7



CONTENTS

Contents

ACN>5+ED)E(EN$ ACN>5+ED )E(EN$........ ................ ................ ................ ................ .............. .......... ........ ........ ........ ........ ........ ....... ... : C>N$EN$-.................... ........................................... .............................................. .............................................. ............................................... .......................... ? Contents....................... .............................................. .............................................. .............................................. .............................................. .............................. ....... ? +I-$ >F FI)UE-.................... ........................................... .............................................. .............................................. ...................................... ............... @ @ +I-$ >F $A0+E-..................... ............................................ .............................................. .......................................................... ...................................... ...   C1AP$E :....................................... .............................................................. ................................................. .......................... ; ; IN$>DUC$I>N..................... ............................................ .............................................. ................................................. .......................... ; ; 1.1 EMP EM P Group Grou p of Compani Companies es........... ....................... ....................... ...................... ................ .......... .......... .......... ....... .. 9 Figure 1.1 – EMP Group Logo....................... Logo................................... ........................ ......................... ...................10 ......10 1.1.1 Range of Service Se rvice of EMP, EM P, EPL & EMP Enginee Engineering ring ...... ........... .......... .......... .......10 1.1. Range of Services Se rvices of !"#er !" #er Mem$ers Me m$ers ........... ....................... ................. .......... .......... ........ ... 10 1. %#e ision  ision & Mission M ission ........... ....................... ....................... ................ .......... .......... .......... .......... .......... .......... ..... 11 1. !rgani'a"ion !rgani'a "ion S"ruc"ure S"ruc"u re ............................ ................ ........................ .................... ............. .......... .......... ....... ..11 1..1 !rgani' !rgani'a"ion a"ion S"ruc"u S"ruc"ure re of o f EMP EM P Group Gro up........... ....................... ...................... ............... ........ ... 11 Figure 1.( !rgani'a"ion S"ruc"ure................................ S"ruc"ure.........................................................11 .........................11 1.. S"ruc"ure of "#e Engineering & )ssem$*+ Sec"ion ...................... 1 1

C1AP$E 7.................................................. .......................................................................... ............................................... ....................................... ................ :? -witc! )ears  Protec Protective tive Functio Functionn ........ ................. ................. ................ ................ ............... ........... ........ ......... ..... :? .1 n"ro-uc"ion n"ro-uc"io n – Si"c# Gears .......... ...................... ........................ ....................... ...................... ............... .... 1/ .1 Circui C ircui"" reaers re aers ............ ....................... ....................... ........................ ....................... ....................... .................. .......... .... 12 ..1 MC........... ....................... ....................... ....................... ........................ ....................... ....................... ................. .......... .......13 ... %ripp %ripping ing Curves C urves ........... ....................... ....................... ....................... ...................... .............. ......... .......... ........ ... 13 ./.1. MCC ........... ...................... ....................... ........................ ....................... ....................... ........................ ................... .........14 ./.. %ec#ni %ec#nica* ca* -a"a of a MCC M CC.......... ...................... ........................ ....................... ..................... ............. ... 14 ././. %rippin %r ipping g )ccessories )ccessor ies ........... ....................... ...................... ............... .......... .......... ......... ......... .......... ........ ... 15 .2.1. ELC & RCC .......... ...................... ........................ ....................... ....................... ........................ .................. ...... 16


?



.3.1. )C )C ............ ........................ ....................... ....................... ........................ .................. ........... .......... .......... .......... .......... .......0

C1AP$E ?.................................................. .......................................................................... ............................................... ....................................... ................ 77 Protective elays  Protective Devices ....................... .............................................. ...................................... ............... 77 77 /.1 n"ro-u n"ro-uc"ion c"ion ........... ...................... ....................... ........................ ....................... ....................... .................... ............. ......... ....  /.. ELR E LR............ ........................ ....................... ....................... ........................ ....................... ..................... ............... .......... .......... ........ ...  /./. EFR........... ...................... ....................... ........................ ........................ ....................... ....................... ................. .......... ......... ....... ... / /.2. PFR P FR........... ....................... ........................ ....................... ....................... ........................ ...................... ............... .......... .......... ........ ... 2 /.3. Surge Surges s anan - Surge Su rge )rres"e )rres"ers rs.......... ...................... ........................ ....................... ....................... ................ .... 4 /.3.1 n"ro-u n"ro-uc"ion c"ion ........... ...................... ....................... ........................ ....................... ....................... .................. ........... ..... 4 /.3. !pera"ing !pe ra"ing %ermino %e rmino*og+ *og+........... ....................... ................... ............ .......... .......... .......... .......... .......... ....... .. 4 /.4 Lig#"ning Lig# "ning ro-s ro -s........... ....................... ....................... ....................... .................... ............. .......... .......... .......... .......... ........ ... 9 /.4.1 n"ro-u n"ro-uc"ion c"ion ........... ....................... ........................ ....................... ....................... ........................ .................. ........... ....... .. 9 /.4. ns"a** ns"a**a"ion a"ion of a Lig#"ni Lig#"ning ng RoRo -............ ........................ ....................... ..................... ............... ....... ..9 /.4./. Groun-in Gr oun-ing g........... ....................... ........................ ....................... ................... ............. .......... .......... .......... .......... ....... .. /0 /.4.2 !"#er accessor accessories ies........... ...................... ....................... ........................ ....................... .................... .............. ..... /0

C1AP$E <.................................................. .......................................................................... ............................................... ....................................... ................ ?: Ca'les,, 5iring  Circui Ca'les Circuits ts ........ ................ ................ ................ ................ ................ ................ ................. ............... .......... ........ ....... ...?: 2.1. Ca$*e Ca $*e Specifica" Spe cifica"ions ions ........... ....................... ........................ ....................... ................. ........... .......... .......... .......... ..... /1 2..1. Ca$*e )na"om+ ............ ....................... ....................... ........................ ....................... ................... ............. ........ ... / 2... Se*ec Se*ec"ion "ion of Ca$*es C a$*es ........... ....................... ........................ ....................... ....................... ................ ......... .......// 2../ S"eps of Ca*cu*a"ing Ca*cu *a"ing "#e Ca$*e Ca$* e for a given *oa-............ .................... ............. ....... /2 2./ Ca$*e L+ing.......... ...................... ........................ ....................... ....................... ........................ ....................... .................. ....... /3 2.2 Ring R ing Circui Circui"s "s & !"#er Specia* Circu Circui"s i"s............ ........................ ....................... ...................... ............./4 2.2.1 Ring Circui Circui""............ ........................ ....................... ....................... ........................ ....................... .................... ........... .. /4 2.2. Conver"ing Conver"ing 2 Po*e MCC for a Sing* Sing*e e P#ase Supp Supp*+ *+ or 7C Supp*+ ...................... .......... ........................ ....................... ....................... ........................ ....................... ....................... .................. ........... .......... ..... /5 2.3 ime"a* *ugs ........... ....................... ........................ ....................... .................... .............. .......... .......... .......... .......... ......... .... /6

Figure <.B  0imetal +ugs...................... ............................................. .............................................. ............................................... ........................ ?; ?; C1AP$E B.................................................. .......................................................................... ............................................... ....................................... ................ <8 Panel 0oards  Distri Distri'ution 'ution 0oards ........ ................ ................ ................ ................ ................. ............... .......... ........ ....... ...<8 3.1 n"ro-uc" n "ro-uc"ion ion ( Pane* Pa ne* oar- .......... ...................... ........................ ....................... ..................... ............... ......... .... 20 3. P Pro"ec"ion 8ngress Pro"ec"ion of a Pane* ........... ....... ........ ........ ........ ........ ........ ....... ...... ... 21 3./ Mo"or Con"ro Con"ro** Circui Circui"s "s........... ....................... ....................... ....................... ........................ ....................... ............. .. 2/ 3.2 Capaci"or Capa ci"or ans  ans........... ....................... ....................... ....................... ................... ............ .......... .......... .......... .......... .......29 3.2.1 7esign ........... ...................... ....................... ........................ ....................... ....................... ................. .......... .......... ......... .... 29 3.2. :ses of ;RC Fuses ........... ....................... ........................ ....................... ....................... ...................... ............ ..31


<



3.2./ :ses of Capaci" Capaci"or or Con"ac"or C on"ac"ors s............ ....................... .................... .............. .......... .......... .......... .......31 3.3 )%S ) %S 8)u"oma"i 8) u"oma"ic c %ransfe %r ansferr Si"c# Si "c#........... ....................... ....................... ...................... ................ ......... .... 3

C1AP$E @.................................................. .......................................................................... ............................................... ....................................... ................ BB C>NC+U-I>N C>NC+U-I >N....... ................ ................. ................ ................ ................ ................ ................ ................ ................ ................. ............. ........ ........ ......... .........BB EFEENCE-...................... ............................................. .............................................. .............................................. ......................................... .................. B@ A00E*IA$I>N-.................... ........................................... .............................................. .............................................. .................................... ............. B9 B9


B

EMP Group of Companies (PVT) LTD


LIST OF FIGURES

Figure :.:  E(P )rou" +ogo:8 Figure :.7/ >rganiation -tructure ..:: Figure :.?  -tructure of Electrical  Assem'ly -ection ...:7 Figure 7.:  $ri""ing Curve 03 of a (C0  its >"erating egions :B Figure 7.7 5iring Diagram of a CC0 ..:; Figure ?.:  Control Diagram of an E+ 7? Figure ?.7  Connection Diagram of an EF.. 7< Figure ?.?  PF wit! a U*$ coil ..7B Figure ?.<  PF wit! a s!unt coil ..7@ Figure ?.B / Construction Conce"t of a -urge Arrester ...79 Figure ?.@ / Anatomy of a -urge .7 Figure ?.9  od $y"e +ig!tning Arrester ..7; Figure ?.  Eart!ing C!am'er ...?8 Figure <.:.a,',c,d,e,f  Ca'le $y"es ?7 Figure <.7  Ca'le adii *ariation wit! Ca'le Diameter ...?B Figure <.?  ing Circuit .?9 Figure <.<  5iring Diagram of DC or -ingle P!ase AC -u""ly to a ? P!ase (CC0 .? Figure <.B  0imetal +ugs ?; Figure B.:  Distri'ution -ystem of a Four -tory 0uilding <8 Figure B.7  Inside view of a "anel wit! cover "lates .+ -tarter.. << Figure B.B  Power Diagram of -tar Delta -tarter...

@



Figure B.@  Control Diagram of a -tar Delta -tarter <@ Figure

B.9



Control

Diagram

of

an

Auto

$ransformer

-tarter

Diagram

of

an

Auto

$ransformer

-tarter

...<9 Figure

B.



Power

.< Figure B.;  P!ase Diagram ....<; Figure B.:8 5iring Diagram of a Ca"acitor 0ank B8 Figure B.::  Ca"acitor Contactors B: Figure B.:7  $y"ical Control Diagram of A$- B? Figure B.:?  Com"lete A$- Control Diagram B<


9



LIST OF TABLES

$a'le <.:  A""ro#imated Current atings According to t!e 5ire -ie ?< $a'le <.7  -electing a""ro"riate ca'le according to t!e "!ase wire .?B $a'le <.?  A""ro#imated Current atings According to t!e 5ire -ie ?B $a'le B.:  IP Protection against -olid 0odies ...<: $a'le B.7  IP Protection against +i=uid .<7






CHAPTER 1 INTRODUCTION

As my first com"ulsory session of industrial training of t!e Engineering degree "rogram, I was a""ointed at E(P )rou" of Com"anies %P*$& +$D, Panagoda. $!is training was arranged for :7 weeks from 89/89/788; to 7@/8;/788;. During t!is "eriod I was assigned in E(P main factory  E(P Pro2ects +anka %P*$& +$D w!ic! is a grou" mem'er of E(P )rou". $!is re"ort consists of t!e e#"erience  knowledge t!at I got during t!e training "eriod. 1.1 EMP Group of Compan!"

E(P )rou" of Com"anies was found in $em"le'urge industrial Estate in :;;7 and it was first known as Electro (etal Pressings %P*$& +$D. In year 7887 it was taken over 'y "resent management and on 7 t! Guly 788@ it was incor"orated as E(P )rou" of Com"anies. $oday E(P is a grou" wit! @ mem'ers w!ic! are s"reading t!eir !ands all over t!e 'usiness and manufacturing world. $!e grou"s of mem'ers are as follows. :. Electro (etal Pressings %P*$& +$D %E(P& 7. E(P Pro2ects +anka %P*$& +$D %EP+& ?. E(P Engineering %P*$& +$D <. A+AN %P*$& +$D B. E(P P*C %P*$& +$D @. >(A$A 5ater (anagement %P*$& +$D 9. -ENA- "lywood %P*$& +$D $!e mot!er com"any E(P, EP+  E(P engineering toget!er addresses t!e market related to t!e electrical field. $!ey !ave "rofessional e#"erience in manufacturing electrical switc! 'oards  relevant ca'le lig!t systems  accessories.


;



Figure :.:  E(P )rou" +ogo 1.1.1 Ran#! of S!r$%! of EMP& EPL ' EMP En#n!!rn#

As mentioned a'ove t!ese ? com"anies are s"ecialied in electrical field  generally t!e designing "art is done 'y E(P Engineering  EP+. $!en t!e w!ole manufacturing "art including t!e fa'rication is done 'y E(P  again t!e installation "art is done 'y EP+. 0rief summary of E(P services are as follows. :. $urnkey electrical "ro2ects for !ig! rise 'uildings, garment industries  a"artment 'uildings 7. Designing  installation of turnkey electrical "ro2ects ?. -u""ly  installation of low voltage main switc! 'oard u" to @888A <. -u""ly  installation of motor control centers B. -u""ly  installation of "ower factor correction ca"acitor 'anks @. -u""ly  installation of ca'le management systems %ca'le ladders, ca'le trunkings  floor 'o#es& 9. -u""ly of :;H e=ui"ment rack systems . $ea  ru''er factory electrification ;. (ini !ydro "ro2ects :8. )enerator installation  commissioning 1.1.( Ran#! of S!r$%!" of O)*!r M!m+!r"

Among ot!er com"anies, A+AN is t!e sole agent for +- Industrial -ystems w!ic! manufactures  distri'utes all ty"e of circuit 'reakers, P+C control units, and electronic e=ui"ments all over t!e world. E(P P*C manufactures =uality conduits  UP*C "i"es in mass scale. >(A$A designs t!e water management systems 


:8



"rovides ideal solutions for t!e market. -ENA- "lywood manufactures "lywood 'oards to t!e -ri +ankan market. 1.( T*! ,"on ' M""on

,"on To &e t$e pro#ider of total electrical engineering solutions ' &e sitc$ &oard manufacturer in compliance it$ e#ol#ing standards to suppl glo&all

M""on In eeping it$ t$e commitment to continuous impro#ement of our engineering products! to deli#er $ig$ *ualit e+pected & t$e customer

1.( Or#an-a)on S)ru%)ur! 1.(.1 Or#an-a)on S)ru%)ur! of EMP Group

E(P )>UP

(anaging C!airman

Director

)eneral (anager

E(P

EP+

E(P Engineering

A+AN

>(A$A

E(P P*C

-ENA-

Figure :.7/ >rganiation -tructure


::



$!e academically =ualified, committed and trained "rofessionally/oriented Electrical Engineers and -killed Electricians along wit! t!e trained sales team dedicated to maintain a satisfied customer 'ase always strive to find t!e rig!t electrical solutions t!at are economical and "ractical. $!ey are dedicating to assure o"timum safety standards in kee"ing wit! international standards.

$!e c!airman, (r.

C!andranandana Diyunuge %0.-c. Eng. %1ons&, A(IE %-+& A(IEE %U&&  t!e managing Director, (r. $. -ures! umara %0.-c. Eng. %1ons&, A(IE %-+&A(IEE %U&& initiated and sustained t!e E(P grou". $!e )eneral (anager (r. 1. P. avi u"asing!e %(0A, -c. Eng. %1ons& C(E(A %-+&, A(IE %-+&, A(IEE %U&, ((0AAA& is dedicating to take t!e grou" toward a =uality "roduction. 1.(.( S)ru%)ur! of )*! En#n!!rn# ' A""!m+/ S!%)on

1ead of Electrical  Assem'ly -ection Electrical  Assem'ly $eam +eader Electrical  Assem'ly $eam

uality $eam +eader uality $eam

Figure :.?  -tructure of Electrical  Assem'ly -ection


:7



CHAPTER ( S0)%* G!ar" ' Pro)!%)$! Fun%)on

(.1 In)rou%)on 2 S0)%* G!ar"

A -witc! gear is defined as a switc!ing6 interru"ting device used in connection wit! generation, transmission, distri'ution and conversion of electric "ower for controlling, metering "rotecting and regulating devices. -witc! gears can 'e categoried to main two areas, "rotective devices and Non/"rotective devices. $!e reaction time is ty"ically 'etween ?8 ms and :B8 ms de"ending u"on t!e age and construction of t!e device. According to t!e re=uirements  ot!er e#ternal factors, some switc! gear may not ideal for t!e re=uirement. Alt!oug! sometimes t!e switc! gear is selected as a'ove, t!ere may 'e some mismatc!ing 'ecause of t!e varia'le factors of t!e switc! gears suc! as 'reaking ca"acity, im"ulse voltage, etc. -everal different classifications of switc!gear can 'e made according to t!e 'elow factors. •

0y t!e current rating.

•

0y 'reaking ca"acity %ma#imum s!ort circuit current t!at t!e device can safely interru"t&

•

•

•

0y voltage classJ o

+ow voltage %less t!an :888 volts AC&

o

(edium voltage %:888/?B,888 volts AC&

o

1ig! voltage %more t!an ?B,888 volts AC&

0y insulating mediumJ o

Air

o

>il

o

*acuum

0y construction ty"eJ o

Indoor %furt!er classified 'y IP %Ingress Protection& class or NE(A enclosure ty"e&


:?


•

•

•

o

>utdoor

o

Industrial

o

etc


0y o"erating met!odJ o

(anually/o"erated

o

(otor/o"erated

o

-olenoid6stored energy o"erated

0y ty"e of currentJ o

Alternating current

o

Direct current

0y a""licationJ o

$ransmission system

o

Distri'ution.

(.1 Cr%u) Br!a3!r"

A circuit 'reaker is an automatically/o"erated electrical switc! designed to "rotect an electrical circuit from damage caused 'y overload or s!ort circuit. Its 'asic function is to detect a fault condition and, 'y interru"ting continuity, to immediately discontinue electrical flow. Unlike a fuse, w!ic! o"erates once and t!en !as to 'e re"laced, a circuit 'reaker can 'e reset %eit!er manually or automatically& to resume normal o"eration. Circuit 'reakers are usually a'le to terminate all current flow very =uicklyJ Circuit 'reakers can 'e categoried to several ty"es. :. (C0 7. (CC0 ?. E+C0  CC0 <. AC0 B. >C0 @. *C0 Among a'ove all ty"es :/< ty"es are commonly used.


:<



(.(.1 MCB

(C0 %(iniature Circuit 0reaker& is a circuit 'reaker wit! o"timum "rotection facilities of over current and s!ort circuit only. $!ese are manufactured for fault level of u" to :8A only wit! o"erating current range of @ to :7B Am"s %t!e ranges are fi#ed&. It is availa'le as single "ole, dou'le "ole, t!ree "ole, and four "ole (C03s. $!ese are used for smaller loads /electronic circuits, !ouse wiring etc. As (C0 reacts for 'ot! over current  s!ort circuit, it avoids over !eating in case of e#cess current  "rovides fire "rotection.

>ver current region

-!ort circuit region

Figure 7.:  $ri""ing Curve 03 of a (C0  its >"erating egions (.(.(. Trppn# Cur$!"

Every (C0 !ave a s"ecified tri""ing curve, 0,C,D or sometimes very s"ecialied curve t!at varies from (C0 'rand to 'rand %e.g. /J   K curves of A00 'reaker&. 0, C  D curves are defined in IEE regulations. $!e relations!i" 'etween current and tri""ing time is usually s!own as a curve, known as t!e (C0Ls tri" c!aracteristic. $!e most im"ortant curves are 0, C and D. $y"e 0 (C0s react =uickly to overloads, and are set to tri" w!en t!e current "assing t!roug! t!em is 'etween ? and B times t!e normal full load current. $!ey are suita'le for "rotecting incandescent lig!ting and socket/outlet circuits in domestic and commercial environments %resistive loads&, w!ere t!ere is little risk of surges t!at could cause t!e (C0 to tri". $y"e C (C0s react more slowly, and are recommended for a""lications involving inductive loads wit! !ig! inrus! currents, suc! as fluorescent lig!ting installations. Facult of Engineering! "ni#ersit of Ru$una%

:B



$y"e C (C0s are set to tri" at 'etween B and :8 times t!e normal full load current. $!is ty"e is generally used. $y"e D (C0s are slower still, and are set to tri" at 'etween :8 and 78 times t!e normal full load current. $!ey are recommended only for circuits wit! very !ig! inrus! currents, suc! as t!ose feeding transformers and welding mac!ines.  curves can also 'e used for motors and transformers 'ut !ave im"roved t!ermal c!aracteristics at :.8B to :.7 times t!e rated current. $!e K curves "rovide "rotection to semiconductors, wit! instantaneous tri" values at two to t!ree times t!e rated current.

(.4.1. MCCB

(CC03s %(oulded Case Circuit 0reakers& are designed for "rotection of low voltage distri'ution systems. $!ey are suita'le for a""lication as main 'reakers  for "rotection of 'ranc!  feeder circuit  connected e=ui"ment. (CC03s "rovide "rotection of s!ort circuit  overload "rotection. For all circuit elements including ca'les, motors etc. $!ey are designed for used in control centers, "anel 'oards  switc! 'oards. $!ey suit t!e re=uirement of lig!ting distri'ution  ot!er "ower circuits. (ain two ty"es of (CC0s are (.4.(. T!%*n%a a)a of a MCCB

It is vitally im"ortant to know t!e "arameters of a (CC0 t!at are essential w!en we selecting a "ro"er (CC0. All t!e tec!nical data of a (CC0 is "rinted in t!e face "late and it is vitally im"ortant to know t!e meanings of t!em. 1. Ra)! Curr!n) 5In6 /J

$!e current w!ic! t!e circuit 'reaker will carry

continuously under s"ecified conditions and on w!ic! t!e time6current c!aracteristics are 'ased. Unless ot!erwise stated In is 'ased on a reference am'ient tem"erature of ?8 degrees centigrade. (. Ra)! Op!ra)ona ,o)a#! 5U!6 /J

$!e nominal line to line voltage of t!e

system s!ould not e#ceed Ue 4. Ra)! n"ua)on ,o)a#! 5U6

/J .$!e !ig!est o"erating voltage t!at will not

cause a dielectric strengt! failure. $!e rated insulation voltage is used as a


:@



"arameter for dielectric strengt! tests. $!e rated insulation voltage must always 'e !ig!er t!an t!e rated o"erating voltage %Ue&. 7. Ra)! Impu"! W)*")an ,o)a#! 5Ump6 89

$!e voltage on w!ic!

clearance distances are 'ased. $!e value of transient "eak voltage t!e circuit 'reaker can wit!stand from switc!ing surges or lig!ting strikes im"osed on t!e su""ly .e.g. Uim" M k*, $ested at k* "eak wit! :.76B8s im"ulse wave. :. U)ma)! Br!a3n# Capa%)/ 5I%u6

/J $!e ma#imum fault current w!ic! can

flow t!roug! wit!out damaging t!e e=ui"ment. $!e calculated "ros"ective fault current at t!e incoming terminals of t!e circuit 'reaker s!ould not e#ceed Icu. ;. S!r$%! Br!a3n# Capa%)/ 5I%"6 /J

$!e ma#imum level of fault current

o"eration after w!ic! furt!er service is assured wit!out loss of "erformance. <. L!) T*rou#* En!r#/ 5I ()6

/J A measure of energy re=uired to 'low t!e fuse

element and so a measure of t!e damaging effect of over current on "rotected devicesO sometimes known as t!e let/t!roug! energy. Uni=ue I 7t "arameters are "rovided 'y c!arts in manufacturer data s!eets for eac! fuse family. $!e energy is mainly de"endent on current and time for fuses. 5!en a fault is occurred, fault energy will flow t!roug! t!e "rotective device. $!at energy is known as t!e let t!roug! energy. -o a good =uality "rotective device must !ave a lesser value of let t!roug! energy =. U)-a)on Ca)!#or/ of a MCCB /J

Every (CC0 !as a utiliation category, Cat. AH or Cat. 0H. Ca). A /J

Category A designates circuit 'reakers not s"ecifically intended for

selectivity wit! devices on t!e load side. In ot!er words circuit 'reakers will discriminate only u" to certain fault levels, a'ove w!ic! discrimination wit! devices on t!e load side cannot 'e guaranteed. Ca). B /J

Category 0 designates circuit 'reakers s"ecifically intended for

selectivity wit! devices on t!e load side. -uc! circuit 'reakers will incor"orate some form of time delay.

(.4.4. Trppn# A%%!""or!"

Unlike CDs %esidual Current Devices& (CC0 !as a tri""ing met!od, w!ic! can o"erates fully mec!anically. Even t!oug! "ower is not su""lied to t!e 'reaker, if it is


:9



in on "osition it can 'e tri""ed using t!e tri" 'utton. 0ut CD cannot 'e tri""ed w!en t!e "ower isn3t su""lied as its tri""ing met!od works from residual current %t!roug! an electrical signal mec!anical system is energied&. $!ere is also a met!od to do t!e tri""ing function of a (CC0 'y using electrical signals %current&. For t!is we !ave to use t!e tri""ing accessories, s!unt coil  U*$ coil w!ic! is normally mounted in t!e rig!t !and seat of t!e case of t!e (CC0. Protection relays are connected to t!ese coils. S*un) Co /J

5!en a current "asses t!roug! t!e s!unt coil it "asses tri""ing signal

to t!e (CC0. In t!e normal o"eration no current must 'e gone t!roug! s!unt coil. If "ower flow continuously t!roug! a s!unt coil, it will 'urn. -o current to t!e s!unt coil is su""lies from out going of t!e 'reaker. U,T %o /J

5!en current doesn3t "ass t!roug! t!e U*$ coil it "asses tri""ing signal

to t!e (CC0. -o to switc! on a 'reaker wit! U*$ coil, t!e coil must 'e "rovided a voltage. -o it must 'e connected to t!e incoming of t!e 'reaker. (.7.1. ELCB ' RCCB

$!ere are two ty"es of E+C0, t!e voltage o"erated device and t!e differential current o"erated device. For t!e convenience of furt!er e#"laining voltage o"erated E+C0 will 'e referred as vE+C0 and differential current o"erating E+C0 will 'e referred as iE+C0. $!e "rinci"le of o"eration of t!e vE+C0 is as follows. Under normal conditions t!e closed contacts of t!e vE+C0 feed t!e su""ly current to t!e load. $!e load is "rotected 'y a metal frame. $!e vE+C0 also !as a relay coil, one end of w!ic! is connected to t!e metal frame and one end connected directly to ground. A s!ock risk will arise if a 'reakdown in t!e insulation occurs in t!e load w!ic! causes t!e metal frame to rise to a voltage a'ove eart!. A resultant current will flow from t!e metalwork t!roug! t!e relay coil to eart! and w!en t!e frame voltage reac!es a dangerous level, e.g. B8 volts, t!e current flowing t!roug! t!e relay coil will 'e sufficient to activate t!e relay t!ere'y causing o"ening of t!e su""ly contacts and removal of t!e s!ock risk. As can 'e seen from t!e a'ove descri"tion, t!is ty"e of E+C0 is essentially a voltage sensing device intended to detect dangerous touc! voltages. $!e level of s!ock


:



"rotection "rovided 'y t!e vE+C0 was somew!at limited as t!ese devices would not "rovide s!ock "rotection in t!e event of direct contact wit! a live "art. An additional "ro'lem wit! t!e vE+C0 was its tendency to 'e tri""ed 'y eart! currents originating in ot!er installations. $!e "rinci"le of o"eration of t!e vE+C0 is as follows. Under normal conditions t!e closed contacts of t!e iE+C0 feed t!e su""ly current to t!e load. $!e load conductors are "assed t!roug! a current transformer %C$&. $!e load conductors act as "rimary windings of t!e transformer. $!e C$ is fitted wit! a secondary winding. Under normal conditions, t!e total current flowing from t!e su""ly to t!e load will 'e t!e same as t!e total current flowing 'ack to t!e su""ly from t!e load. As t!e currents in 'ot! directions are e=ual 'ut o""osite, it !as no effect on t!e C$. 1owever, if some current flows to eart! after t!e iE+C0, "ossi'ly due to an eart! fault, t!e current flowing to t!e load and from t!e load will 'e different. $!is differential current will cause a resultant out"ut from t!e C$. $!is out"ut is detected and if a'ove a "redetermined safe level, it will cause t!e iE+C0 to tri" and disconnect t!e su""ly from t!e load. Now differential current o"erating E+C0 is referred as CC0 and "rovides ? ty"es of "rotection. :. 0asic Protection/ Protective measure against direct contact 7. Fault Protection / Protective measure against indirect contact ?. Additional Protection  (a#imum current allowa'le for a fault


:;



Figure 7.7 5iring Diagram of a CC0 (.:.1. ACB

AC0%air circuit 'reaker& is an electric "rotecting a""aratus w!ic! is installed 'etween an electric source and load units in order to "rotect a load unit and a load line from an a'normal current generated on an electric circuit and to "erform distri'ution function for c!anging t!e electric "ower line to anot!er line. $!e electrical systems in residential, commercial and industrial a""lications usually include a "anel 'oard for receiving electrical "ower from a utility source. $!e "ower is t!en routed t!roug! over current "rotection devices to designated 'ranc! circuits su""lying one or more loads. Electrical "ower distri'ution systems and t!eir com"onents need "rotection from numerous ty"es of malfunctions, including over current conditions, overvoltage conditions, under voltage conditions, reverse current flow, and un'alanced "!ase voltages. If a (CC0 is used instead of an AC0 it is essential to connect "rotection relays to "rotect load from a'ove malfunctions. )enerally AC0 is availa'le from :788A to @<88A for low voltage a""lications. Air circuit 'reakers include o"erating mec!anisms t!at are mainly e#"osed to t!e environment. -ince t!e air circuit 'reakers are rated to carry several t!ousand am"eres of current continuously, t!e e#"osure to convection cooling air assists in kee"ing t!e o"erating com"onents wit!in reasona'le tem"erature limits. A ty"ical air circuit 'reaker com"rises a com"onent for connecting an electrical "ower source to electrical "ower consumer or load. $!e com"onent is referred to as a main contact assem'ly. A main contact is ty"ically eit!er o"ened, interru"ting a "at! for "ower to travel from t!e source to t!e load, or closed, "roviding a "at! for "ower to travel from t!e source to t!e load. In many air circuit 'reakers, t!e force necessary to o"en or close t!e main contact assem'ly is "rovided 'y an arrangement of com"ression s"rings. In many air circuit 'reakers, t!e mec!anism for controlling t!e com"ression s"rings com"rises a configuration of mec!anical linkages 'etween a latc!ing s!aft and an actuation device. $!e actuation device may 'e manually or electrically o"erated. In a common construction of a low voltage air circuit 'reaker, t!e mova'le contact is mounted on a contact arm t!at is "ivoted to o"en t!e contacts 'y a s"ring "owered o"erating mec!anism triggered 'y a tri" unit res"onsive to an over current condition


78



in t!e "rotected circuit. *arious accessory devices are used wit! suc! air circuit 'reakers to "rovide au#iliary function along wit! over current "rotection. >ne suc! accessory is t!e 'ell alarm accessory t!at "rovides local and remote indication as to t!e occurrence of circuit interru"tion.


7:



CHAPTER 4 Pro)!%)$! R!a/" ' Pro)!%)$! D!$%!"

4.1 In)rou%)on

5!en manufacturing a "anel 'oard it is essential to !ave some "rotective met!ods ot!er t!an 'reakers w!ic! "rovide additional "rotection to t!e "anel 'oard, e=ui"ments t!at are connected to t!e "anel 'oard and t!e user. For t!is case "rotective relays and ot!er "rotective devices suc! as surge arresters and fuses can 'e used. 5!en considering a'out "rotective relays, it doesn3t act a "rotective function alone. It needs some tri""ing accessories mounted in a (CC0 suc! as descri'ed in c!a"ter 7.?.?, to "rovide t!e "rotective function. As "anel 'oard is t!e !eart of t!e distri'ution system of 'uilding it is vitally im"ortant to !ave "rotective met!ods. 4.(. ELR

E+ %Eart! +eakage elay& ensures t!e "rotection of electrical installations and "erson against direct and indirect contacts. E+ is designed on an electronic 'asis, w!ic! ensures t!e monitoring of eart! fault currents. 5!en t!e fault current rises a'ove t!e selected level, t!e out"uts of t!e "roduct o"erate de"ending on t!e relay selected, it can !ave eit!er fi#ed or ad2usta'le settings for selectivity "ur"oses. 0ot! minimum leakage current and also t!e tri""ing current can 'e ad2usted in an E+. $!is is an advantage of an E+ t!an a CC0. $o o"erate an E+ it must 'e connected to a C0C$ %Core 0alance Current $ransformer&.$!e function of an E+ is as 'elow %Figure ?.7.:&. It is known t!at at any instant t!e alge'raic sum of currents in ? "!ase 'alanced su""ly is e=ual to ero. -o at normal condition, total alge'raic sum of currents in four wires %? "!ases and neutral& must 'e ero. -o at normal conditions no current s!ould 'e generating in t!e C0C$. 5!en a leakage !a""ens t!en t!ere will 'e a leakage current and ultimately alge'raic sum of current t!roug! C0C$ will not 'e e=ual to Kero and as a result of t!at t!e current will 'e induced in t!e C0C$. $!is current "rovides a signal to E+ and it 'egins to o"erate and closes its normally o"en contact. $!en t!ere will 'e a Facult of Engineering! "ni#ersit of Ru$una%

77



current t!roug! t!e s!unt coil and t!en s!unt coil "asses a tri""ing signal to t!e (CC0. %It is known t!at if t!ere is a current t!roug! a s!unt coil it will "rovide a tri""ing signal to a (CC0&. E+ is used wit! (CC0s wit! current rating less t!an 7B8A. L1

(CC0

C0C$

L2

L3

N

Fuse 7 Au#iliary -u""ly Fuse :

N>

-:

E+

-7

-!unt Coil

Figure ?.:  Control Diagram of an E+

4.4. EFR

EF %Eart! Fault elay& is used for "rotecting from eart! faults and use wit! (CC0s wit! current rating greater t!an 7B8A. $!e function of EF is as same as E+, 'ut more sensitive t!an E+. Instead of a C0C$, four se"arate C$3s are used to connect an EF. It is an Electronic $ri" Unit, designed to "rotect t!e Electrical installation in case of faults or leakage currents 'eyond a "reset level. $!e tri" delay is ad2usta'le.


7?

EMP Group of Companies (PVT) LTD +:

+7

+?


N Fuse 7

Au#iliary -u""ly

(CC0

Fuse : N>

EF

-!unt Coil

C$s

Figure ?.7  Connection Diagram of an EF 4.7. PFR

PF %P!ase Failure elay or P!ase *oltage 0alance elay& is a t!ree/"!ase voltage sensing device t!at tri"s on "!ase loss, "!ase reversal, over voltage, or under voltage. *oltage un'alance tri"s t!e device w!en any voltage dro"s certain "ercentage %around :8Q& 'elow t!e average. Under voltage is e#ternally ad2usta'le from 9B:88Q of t!e rated voltage %De"ends u"on t!e 'rand and ty"e&. $!e +ED on t!e front of t!e device lig!ts w!en t!e device is energied. For t!e "rotection of ? "!ase loads ti! can 'e installed. )enerally a PF is used along wit! an U*$ coil. 0ut a disadvantage of t!is is w!en incoming su""ly cuts off, PF considers it as a fault and tri"s t!e circuit. $!en some'ody !as to switc! on t!e 'reaker after "ower comes. $o avoid t!is distur'ance


7<



sometimes s!unt coil is used instead of a U*$. 0ut it !as some disadvantages also. 5!en a failure of a "!ase w!ic! "rovides voltage to t!e s!unt coil, occurs t!en PF cannot send t!e tri""ing signal. >f course t!is matter can 'e avoided 'ut it is a little 'it e#"ensive.

+:

+7

+?

N

F u s e:

N > F u s e7 F u s e? F u s e<

P F  U * $ C o il

(CC0

Figure ?.?  PF wit! a U*$ coil


7B

EMP Group of Companies (PVT) LTD +:

+7

+?


N

F u s e: F u s e7 F u s e? F u s e<

P F (CC0

F u s eB $imer N >

N C -!unt Coil

$imer Coil

Figure ?.<  PF wit! a s!unt coil 4.:. Sur#!" an Sur#! Arr!")!r" 4.:.1 In)rou%)on

$!e lig!tning arresters and ground wires can well "rotect t!e electrical system against direct lig!tning strokes 'ut t!ey fail to "rovide "rotection against travelling waves, w!ic! may reac! t!e terminal a""aratus. $!e surge arresters or surge diverters "rovide "rotection against suc! surges. A lig!tning arrester or a surge diverter is a "rotective device, w!ic! conducts t!e !ig! voltage surges on t!e "ower system to t!e ground. 4.:.( Op!ra)n# T!rmnoo#/

)enerally -urge arrester is assem'led at t!e incoming side of an every main distri'ution 'oard. $!e construction conce"t of a surge arrester is as s!own 'elow.


7@



Figure ?.B / Construction Conce"t of a -urge Arrester Fig ?.B.%i& s!ows t!e 'asic form of a surge arrester. It consists of a s"ark ga" in series wit! a non/linear resistor. >ne end of t!e arrester is connected to t!e terminal of t!e e=ui"ment to 'e "rotected %generally a distri'ution 'oard& and t!e ot!er end is effectively grounded. $!e lengt! of t!e ga" is so set t!at normal voltage is not enoug! to cause an arc 'ut a dangerously !ig! voltage will 'reak down t!e air insulation and form an arc. $!e "ro"erty of t!e non/linear resistance is t!at its resistance increases as t!e voltage %or current& increases and vice/versa. $!is is clear from t!e voltage current c!aracteristic of t!e resistor s!own in Fig ?.B.%ii&. Under normal o"eration, t!e lig!tning arrester is off i.e. it conducts no current to eart! or t!e ga" is non/conducting. >n t!e occurrence of over voltage, t!e air insulation across t!e ga" 'reaks down and an arc is formed "roviding a low resistance "at! for t!e surge to t!e ground. In t!is way, t!e e#cess c!arge on t!e line due to t!e surge is !armlessly conducted t!roug! t!e arrester to t!e ground instead of 'eing sent 'ack over t!e line. It is wort!w!ile to mention t!e function of non/linear resistor in t!e o"eration of arrester. As t!e ga" s"arks over due to over voltage, t!e arc would 'e s!ort/circuited on t!e "ower system and may ground t!e surge. -ince t!e


79



c!aracteristic of t!e resistor is to offer low resistance to !ig! voltage %or current&, it gives t!e effect of s!ort/circuit. After t!e surge is over, t!e resistor offers !ig! resistance to make t!e ga" non/conducting. 0ut t!oug! a lig!tning !as t!e strengt! a'out 788kA, generally a surge arrester of :8kA is assem'led in a main "anel  BkA for a 'ranc! "anel for t!e "rotection %or ot!erwise only one 78kA surge arrester for t!e main "anel  no surge arresters for 'ranc! "anel&. $!is is a contradiction. +et3s clear t!is, consider 'elow figure.

Figure ?.@ / Anatomy of a -urge -u""ose a surge of 7:8kA occurs on a ? "!ase transmission line. $!en for a single "!ase t!e surge will 'e98kA. In t!e transmission line it can flow t!roug! 'ot! directions. -o t!e surge for one side will 'e ?BkA. $!e arrester of distri'ution transformer t!en diverts a'out 78kA to t!e ground. 5!en t!e rest of t!e surge, :BkA meets t!e main "anel surge arrester, it will 'e diverted to t!e eart! %if "ossi'le ca"acity of a surge arrester& or t!e rest "art of t!e surge will 'e grounded 'y 'ranc! "anel surge arresters.


7



4.; L#*)nn# ro" 4.;.1 In)rou%)on

+ig!tning is an un"redicta'le event t!at can affect our electrical system any time w!ic! !as t!e !ig! current ca"acity  !ig! voltage ca"acity. Direct effects are from resistive %o!mic& !eating, arcing and 'urning. Indirect effects are more "ro'a'le. >n a 'uilding wit!out lig!tning "rotection, t!ose same millions of volts of electricity still !ave to get to t!e ground. +ig!tning will use t!e electrical wiring, tele"!one or ca'le wiring, structural elements of t!e 'uilding, or anyt!ing else it can find as a "at! to ground. None of t!ese 'uilding elements is designed to safely carry t!is amount of electricity. $!e result is a 'uild/u" of resistance, w!ic! leads to fire and e#"losive damage to t!e 'uilding. -till it is im"ossi'le to guarantee :88Q a'out a lig!tning "rotection. 0ut some "ercentage of "rotection can 'e taken from installing lig!tning arresters. $!ere are various ty"es of lig!tning arresters. Among t!at finial rod ty"e lig!tning arrester is t!e most common ty"e. $!is is made out of "ure co""er. +ig!tning rod is t!e e=ui"ment t!at directly acts wit! a lig!tning.

Figure ?.9  od $y"e +ig!tning Arrester

4.;.( In")aa)on of a L#*)nn# Ro

$!e lig!tning rod must 'e installed in an a""ro"riate angle to "rotect t!e 'uilding. $!is "rotection angle varies according to t!e ca"acity of t!e lig!tning. )enerally, lig!tning arrester is fi#ed in a !eig!t t!at includes t!e 'uilding in

7;



According to to" area of t!e 'uilding multi"le arresters may 'e used. +ig!tning rods must 'e "laced at regular intervals, "refera'ly 78 feet a"art, at most. $!e end rods s!ould 'e installed wit!in at least one foot of t!e end of t!e roof, t!oug! two feet, at most, is acce"ta'le. $!e most suita'le, 'ut most cost way of fi#ing over !ead s!ield is t!e Faraday cage, co""er "late net wit! 7#7 s=uare feet s=uares. 0ut as t!is is very !ig! in cost, a co""er ta"e is run around t!e to" of t!e 'uilding  'ottom of t!e 'uilding. $!en t!ese two rounds are connected wit! co""er ta"e %'y all four sides or at least two sides&. 4.;.4. Grounn#

After "ro"er grounding is connected, t!e eart! resistance must 'e smaller t!an :8 o!ms. De"ending on t!e eart! resistance num'ers of grounding rods are varied. At least 7 rods are grounded at a distance same as t!e de"t! of t!e rod for grounding. De"ending on t!e sie of your !ouse, at least 7 groundings will 'e needed. If t!e 'uilding is larger in "erimeter t!an 7B8 feet 'ut less t!an ?B8, t!e 'uilding needs t!ree groundings. If t!e "erimeter is 'etween ?B8 and
A yellow 'ow must 'e ke"t to disconnect t!e grounding rod wit! t!e lig!tning rod to measure t!e ground resistance time to time. And also eart!ing c!am'er must also 'e ke"t

Figure ?.  Eart!ing C!am'er


?8



CHAPTER 7 Ca+!"& Wrn# ' Cr%u)"

In electrical systems, ca'les are used for carrying electrical currents. (ost times core of t!ese ca'les are made of co""er or Aluminum to conduct current wit! minimum voltage dro". (ost ca'les !ave a "rotective insulation to "rotect t!e ca'le  also to "rotect living 'eings from dangerous voltages. $y"es of ca'les are differ according to t!e, :. Current go t!roug! %ca'le sie& 7. Pur"ose t!ey are used ?. Place %indoor or outdoor& <. Protection level re=uired B. Etc. (ainly t!e ca'le ty"es can 'e categoried to 'elow grou"s. :.

)eneral Ca'les %ca'les w!ic! are used for general "ur"oses&

7.

Fle#i'le Ca'les

?.

Aluminum Ca'les %0are conductors&

<.

Armored Ca'les

B.

Unarmored Ca'les

@.

Auto Ca'les

9.

Coa#ial Ca'les

.

$elecommunication Ca'les

7.1. Ca+! Sp!%f%a)on"

As "reviously said ty"es of ca'les t!at are used is differs from various reasons. )enerally 'are conductors are used for t!e transmission  distri'ution of low, medium  !ig! voltage. Armored  unarmored ca'les are used for t!e distri'ution of electricity wit! in cities, factories  'uildings. $!ey are directly laid in ground w!ere e#cessive mec!anical stresses likely to occur. $!oug! t!e armored ca'les don3t need any e#cess "rotection, unarmored ca'les must 'e "rovided some additional "rotection. >t!er ma2or ty"e of ca'le used in low voltage distri'ution in rural  semi ur'an areas is A0C %Arial 0undled Conductors& Ca'les. $!ese are only few t!ings a'out ca'les Facult of Engineering! "ni#ersit of Ru$una%

?:



7.(.1. Ca+! Ana)om/

0elow are some ty"es of ca'les t!at !ave e#"lained a'ove.

<.:.a

<.:.'

<.:.c

<.:.d

<.:.e

<.:.f

Figure <.:.a,',c,d,e,f  Ca'le $y"es


?7



From a'ove figures it can 'e seen t!at some ca'les are consists of several strands. It can 'e o'served t!at t!oug! t!e ca'les !ave same cross sectional area if t!e num'er of strands of ca'le is !ig!er t!an t!e ot!er it can carries a larger current t!an ot!er one. $!is incident !a""ens 'ecause of electrons. Normally c!arges %!ere electrons& stays in t!e surface of any conductive element. $!e num'ers of strands are increased means t!at t!e surface area of t!e ca'le is increased. $!at means it can take more electrons %current&. -o, t!an ot!er ca'les of same sie fle#i'le ca'les can take larger currents. 7.(.(. S!!%)on of Ca+!" ,o)a#! Drop

*oltage dro" is t!e reduction in voltage in an electrical circuit 'etween t!e source and load. 5!en a ca'le is 'eing selected for taking current for a s"ecified mac!ine, as "er IEEE regulations it is re=uired to !ave t!e voltage dro" of t!e ca'le less t!an
All t!e ca'les in t!e market are marked for a current t!at it can carry under standard conditions. 0ut always t!ese standard conditions cannot 'e ke"t "ractically, in a construction. -o if a ca'le is selected according to t!e re=uirements %current& according to our assem'le met!od t!ere can 'e variations of current. $!e factors t!at are affecting for a'ove variations are called as derating factors. $!ey are, :. Am'ient tem"erature 7. )round tem"erature ?. De"t! of lying <. -oil $!ermal resistivity


??



-o if a ca'le is 'eing selected, we must consider derating factors w!ic! are mentioned in ca'le catalogues. 7.(.4 S)!p" of Ca%ua)n# )*! Ca+! for a #$!n oa

+et, we are given to calculate suita'le ca'le sie for a mac!ine w!ic! !ave known "ower consum"tion, nown in"ut voltage. And also t!e distance from "ower su""ly to load %+& is "rovided. $!en, •

Using t!e given data, calculate t!e load current I.

•

-elect a wire t!at is a little 'igger to carry I %Iwire T I&

•

$!en multi"ly t!e rated current of selected wire wit! all t!e derating factors.

•

Find w!et!er, Iwire # derating factors  I

•

If so select ne#t 'igger wire sie. If not select t!at wire

•

$!en calculate t!e voltage dro" of wire  nominal voltage dro"  see w!et!er it is ok.

7.(.7 Norma Curr!n) Ra)n#" for Wr!"

Current ratings for wires differ from manufacturer to manufacturer, t!oug! t!ey are almost similar. 0elow s!ows t!e a""ro#imated current ratings for given wire sies under standard conditions. 5ire sie

Current ating

%s=. mm& %A& : :7 :.B :@ 7.B :; < 7< @ ?7 :8 <8 :@ @8 7B :88 ?B :7B B8 :@8 98 788 98 77B ;B 7B8 :78 ?88 :B8 ?B8 :B <88 $a'le <.:  A""ro#imated Current atings According to t!e 5ire -ie Facult of Engineering! "ni#ersit of Ru$una%

?<



According to t!ese current ratings a""ro"riate eart! ca'les !ave to 'e selected. According to IEC regulations, selection of "rotective eart! ca'le is as follows. Cro""8"!%)ona ar!a of p*a"! %onu%)or" S

mm7 -V :@  - V ?B  - V <88  - V 88  -

Mnmum %ro""8"!%)ona ar!a of )*! %orr!"ponn# pro)!%)$! %onu%)or 5PE& PEN6 Sp

mm7 :@ -67 788 -6<

:@ ?B <88 88

$a'le <.7  -electing a""ro"riate ca'le according to t!e "!ase wire Note t!at t!e values in ta'le are valid only if t!e "rotective conductor is made of t!e same metal as t!e "!ase conductors. 7.4 Ca+! L/n#

5!en a ca'le is 'eing laid it is im"ortant, 'ut generally forgotten factor is ca'le 'ends. As "er IEEE regulations according to ca'le diameter, t!e internal radii of ca'le vary as follows. r

D

Figure <.7  Ca'le adii *ariation wit! Ca'le Diameter Ca+! Dam!)!r Ran#! 5mm6

Mnmum n)!rna ra 5mm6 8 r

D  :8 :8  D  7B 7B  D P*C6W+PE insulated armored circular

D#? D#< D#@ D#@

conductors P*C6W+PE insulated armored or

D#

unarmored solid Al or s!a"ed Cu conductors $a'le <.?  A""ro#imated Current atings According to t!e 5ire -ie


?B



7.7 Rn# Cr%u)" ' O)*!r Sp!%a Cr%u)" 7.7.1 Rn# Cr%u)

ing circuit is "rovided two inde"endent conductors for live, neutral and "rotective eart! wit!in a 'uilding for eac! connected load or socket. $!is design ena'les t!e use of smaller/diameter wire t!an would 'e used in a radial circuit of e=uivalent total current. Ideally, t!e ring acts like two radial circuits "roceeding in o""osite directions around t!e ring, t!e dividing "oint 'etween t!em de"endent on t!e distri'ution of load in t!e ring. If t!e load is evenly s"lit across t!e two directions, t!e current in eac! direction is !alf of t!e total, allowing t!e use of wire wit! !alf t!e current/carrying ca"acity. In "ractice, t!e load does not always s"lit evenly, so t!icker wire is used. Anot!er advantage of ring circuits was an economy of ca'le and la'or, as one could connect a ca'le 'etween two e#isting :B A radially wired sockets to make one ?8 A ring, t!en adding as many sockets as were desired. $!is would leave t!e ring su""lied 'y two :B A fuses, w!ic! worked well enoug! in "ractice, even if unconventional. ules for ring circuits say t!at t!e ca'le rating must 'e no less t!an two t!irds of t!e rating of t!e "rotective device. $!is means t!at t!e risk of sustained overloading of t!e ca'le can 'e considered minimal. In "ractice, !owever, it is e#tremely uncommon to encounter a ring wit! a "rotective device ot!er t!an a ?8 A fuse. $!e IEE 5iring egulations %0- 9@9:& "ermit an unlimited num'er of socket outlets to 'e installed on a ring circuit, "rovided t!at t!e floor area served does not e#ceed :88 m7. In "ractice, most small and medium !ouses !ave one ring circuit "er storey, wit! larger "remises !aving more. ing circuits can !ave e#tra sockets added to t!em 'y adding a Ls"urL onto a ring circuit. A s"ur is a 'ranc! off t!e ring circuit, usually from an e#isting circuit, alt!oug! a 2unction 'o# could also 'e used. $!eoretically as many s"urs as sockets could 'e added, 'ut t!e ma#imum load of t!e circuit %?86?7am"& still e#ists&. $o e#tend a s"ur furt!er more a fuse must 'e connected. $!e rating of t!e fuse is decided according to t!e "ower factor  t!e num'er of socket outlets.


?@



Fuse

7.Bmm wires

:.Bmm wires

:.Bmm wires

7.Bmm wires

Fuse 7.Bmm wires

?8A Fuse

Power -u""ly

Figure <.?  ing Circuit 7.7.( Con$!r)n# 7 Po! MCCB for a Sn#! P*a"! Supp/ or DC Supp/

$!e "rotective e=ui"ments w!ic! is !aving over current "rotection, sometimes don3t activate for an over current in one line only. It only activates if over current goes t!roug! all ? "!ases. In t!is case, if we wire an over current relay or a t!ermal magnetic (CC0 'y using only 7 "oles t!e "rotection system may not work "ro"erly. $o avoid t!is case it is wired as 'elow.


?9



L

N

L

N

Figure <.<  5iring Diagram of DC or -ingle P!ase AC -u""ly to a ? P!ase (CC0 $!is connection allows e=ual !eating in all ? "!ases in case of a over current in t!e "rovided "!ase.

7.: Bm!)a u#"

5!enever aluminium ca'le is to 'e terminated on co""er 'us 'ar or co""er contact, if aluminium lug is used t!en contact 'etween terminal lug and co""er 'us 'ar 'eing of dissimilar metals, galvanic action takes "lace. Also if co""er lug is used t!en contact 'etween aluminium ca'le and 'arrel of co""er terminal lug is of dissimilar metal and !ence t!e galvanic action takes "lace. In order to "revent dissimilar contact and to avoid galvanic action it is always advisa'le to use co""er aluminium 0i/(etal lugs. In 0i/(etal lugs 'arrel of t!e lug is of aluminium and t!e !ead or "alm of t!e lug is of co""er. $!is ensures contact 'etween aluminium ca'les to terminal lug is of aluminium and contact 'etween terminal lug to co""er 'us 'ar or contact is of co""er. $!us contact 'etween dissimilar metal is avoided and contact 'etween similar metal is esta'lis!ed. $!us 0i/(etallic or galvanic action is com"letely eliminated and !ence dura'le 2oint is ac!ieved. Electrolytic co""er !ead 6 "alm is friction welded to electrolytic aluminium 'arrel. At t!e interface, co""er molecules and aluminium molecules intermingles wit! eac! ot!er and form dura'le 'ond. -imilarly if aluminium ca'le is to 'e 2oined wit! co""er ca'le t!en 0i/(etal in line connectors are to 'e used. 1ere for aluminium ca'le


?



aluminium 'arrel is "rovided and for co""er ca'le co""er 'arrel is "rovided. Co""er and aluminium 'arrels are friction welded. De"ending u"on a""lication 0i/(etal terminals, in line connectors, "in ty"e connectors etc are manufactured.

F#ur! 7.: 2 Bm!)a Lu#"


?;



CHAPTER : Pan! Boar" ' D")r+u)on Boar"

:.1 In)rou%)on 8 Pan! Boar

A "anel 'oard %or distri'ution 'oard& is a com"onent of an electricity su""ly system w!ic! divides an electrical "ower feed into su'sidiary circuits, w!ile "roviding a "rotective fuse or circuit 'reaker for eac! circuit, in a common enclosure. Normally, a main switc!, and in recent 'oards, one or more esidual/current devices %CD& or esidual Current 0reakers wit! >ver current "rotection %C0>&, will also 'e incor"orated. at!er t!an "roviding se"arate "rotection systems, it is easier to use a "anel 'oard. $!e main advantage of a "anel 'oard is, all t!e outgoing "ower circuits  incoming "ower can 'e controlled at a single location. -ince "anel 'oards are wit! "rotection systems it su""lies overall "rotection to its su'sidiary circuits. 5!en a construction of a !ig! rise 'uilding or a factory, it is easy to use "anel 'oards  su' D03s  also "anel 'oards "rovides !ig! "rotection  neat electric work for t!e 'uilding.

Sub DB Floor 4

Sub DB Floor 3 Main Power Supply

Main Panel Sub DB Floor 2

Sub DB Floor 1

Electrical components Floor 4




Figure B.:  Distri'ution -ystem of a Four -tory 0uilding


<8



:.( IP Pro)!%)on 5In#r!"" Pro)!%)on6 of a Pan!

A two/digit num'er esta'lis!ed 'y t!e International Electro $ec!nical Commission is used to "rovide an Ingress Protection rating to a "iece of electronic e=ui"ment or to an enclosure for electronic e=ui"ment. $!e "rotection class after EN@8B7; is indicated 'y s!ort sym'ols t!at consist of t!e two code letters IP and a code numeral for t!e amount of t!e "rotection. IP >> 5e.g.  IP B< 6 $!e two digits re"resent different forms of environmental influenceJ X $!e first digit re"resents "rotection against ingress of solid o'2ects. X $!e second digit re"resents "rotection against ingress of li=uids. $!e larger value of eac! digit, t!e greater t!e "rotection. As an e#am"le, a "roduct rated IPB< would 'e 'etter "rotected against environmental factors t!an anot!er similar "roduct rated as IP<7. IP rating ta'les are as 'elow. IP First num'er / Protection against solid o'2ects

8

No s"ecial "rotection

:

Protected against solid o'2ects u" to B8 mm, e.g. accidental touc! 'y "ersons !ands.

7

Protected against solid o'2ects u" to :7 mm, e.g. "ersons fingers.

?

Protected against solid o'2ects over 7.B mm %tools and wires&.

<

Protected against solid o'2ects over : mm %tools, wires, and small wires&.

B

Protected against dust limited ingress %no !armful de"osit&.

@

$otally "rotected against dust. $a'le B.:  IP Protection against -olid 0odies


<:



IP -econd Num'er  Protection against li=uid

8 : 7 ? <

No "rotection. Protection against vertically falling dro"s of water e.g. condensation. Protection against direct s"rays of water u" to :Bo from t!e vertical. Protected against direct s"rays of water u" to @8o from t!e vertical. Protection against water s"rayed from all directions / limited ingress

B

"ermitted. Protected against low "ressure 2ets of water from all directions / limited

@

ingress. Protected against tem"orary flooding of water, e.g. for use on s!i"

9 

decks / limited ingress "ermitted. Protected against t!e effect of immersion 'etween :B cm and : m. Protects against long "eriods of immersion under "ressure. $a'le B.7  IP Protection against +i=uid

According to a'ove two c!arts it can 'e seen t!at t!ere must 'e some ways to increase t!e "rotection of a "anel 0oard. $!ey are, •

E=ual t!ickness of "owder coating according to t!e standards  Insulate enclosure to "revent !aards u" to some level in case of a fault condition

•

Doors for "anel 'oards wit! "ro"erly assem'led  eart!ed

•

Cover "lates w!ic! are tailor made for t!e "anel  "rovides additional "rotection after door is o"ened

•

Insulation of t!e 0us 'ars  Pers"e# s!eets  "rovides additional "rotection after cover "lates are removed

•

Panel eart!ing  to ground in case of fault current

•

Using glands in ca'le ca'le entries

-ometimes, al'eit rarely, t!e o"tional c!aracters t!ree and6or four may 'e used as followsJ •

?rd C!aracter  >"tional access to live "arts %A,0,C,D& :. A / 0ack of !and 7. 0 / Finger ?. C / $ool


<7



<. D / 5ire •

"tional -u""lementary Information % 1,(,-,5& :. 1 / 1ig! voltage a""aratus 7. ( / (otion during water test ?. - / -tationary during water test <. 5 /5eat!er conditions

Figure B.7  Inside view of a "anel wit! cover "lates

:.4 Mo)or Con)ro Cr%u)"

(ainly, ? ty"es of motor control circuits were learnt in detail during t!e training "eriod. $!ey are, :. Direct >n +ine -tarter %D>+ starter& U1 1 !1 U1

1

!1

7. -tar Delta -tarter ?. Auto $ransformer -tarter !2

DOL S)ar)!r 

U2

2

!2

U2

2

'ars $!is starter ty"e is used for small motors,Cunormally motors w!ic!

$erminal connection of (otor

-tar connection of (otor

!ave "ower less t!an :8k5. If t!e motor ty"e wanted is -tar or Delta %5e can configure it&, it must me manually connected. $!at means during t!e o"eration we 1 !1 ? co""er 'ars w!ic! are "rovided wit! t!e cannot c!ange t!e motor U1 ty"e. $!ere are

motor,  using t!ose, t!e motor can 'e configured as 'elow. Cu 'ar !2

U2

2

Delta connection of (otor




Figure B.?  $erminal Connections of (otors After motor is configured to star or delta, t!e su""ly s!ould connect to t!e terminals U:, *:, 5: according to t!e 'elow diagram. U

*

5 1C Fuse

+ Emergency -to"

.: Contactor

Pus! >N

Pus! >FF

.:

>ver Current elay .:

M

N

Figure B.<  Power  Control Circuit Diagram of a D>+ -tarter S)ar D!)a S)ar)!r


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$o decrease t!e starting current cage motors of medium and larger sies are started at a reduced su""ly voltage. $!e reduced su""ly voltage starting is a""lied in t!e -tar Delta met!ods. $!is is a""lica'le to motors designed for delta connection in normal running conditions. 0ot! ends of eac! "!ase of t!e stator winding are 'roug!t out as si# terminals. For starting, t!e stator windings are connected in star and w!en t!e mac!ine is running t!e switc! is t!rown =uickly to t!e running "osition 'y automatically %It can 'e done manually also&, t!us connecting t!e motor in delta for normal o"eration. $!e "ower diagram of -tar Delta starter is s!own 'elow. U

*

5

1C Fuse

 D Delta Contactor

 + +ine Contactor

 -tar Contactor

>verload elay

M

U

*

5

Figure B.B  Power Diagram of -tar Delta -tarter




5!en t!e motor is started in t!e star connection, t!e "!ase voltage of t!e motor is reduced 'y a factor of YZ?. $!e starting line current of t!e motor will 'e reduced to a :6? value of D>+ Delta starting. And ultimately "ower of t!e motor will 'e reduced to a factor of :6?. A disadvantage of t!is met!od is t!at t!e starting tor=ue %w!ic! is "ro"ortional to t!e s=uare of t!e a""lied voltage& is also reduced to :6? of its delta value. Note t!at all si# terminals of t!e motor are connected to wires. No co""er 'ars are used to configure t!e Delta connectionO it is automatically done 'y t!e contactors according to t!e control circuit. At t!e starting moment, line contactor  star contactor are energied. After a time delay w!ile star contactor is 'eing de/energied, t!e Delta contactor will 'e energied  work as a D>+ Delta motor. $!e control circuit of star delta starter is as 'elow. +

Emergency -to" Pus! >N

. +

Pus! >FF

$:

$:

. D $imer $:

. +

. -

. -

. D

N

Figure B.@  Control Diagram of a -tar Delta -tarter

Au)o Tran"form!r S)ar)!r


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$!is met!od also reduces t!e initial voltage a""lied to t!e motor and t!erefore t!e starting current and tor=ue. $!e motor, w!ic! can 'e connected "ermanently in delta or in star, is switc!ed first on reduced voltage from a ?/"!ase ta""ed auto /transformer and w!en it !as accelerated sufficiently, it is switc!ed to t!e running %full voltage& "osition. $!e "rinci"le is similar to star/delta starting and !as similar limitations. $!e advantage of t!e met!od is t!at t!e current and tor=ue can 'e ad2usted to t!e re=uired value, 'y taking t!e correct ta""ing on t!e autotransformer. $!is met!od is more e#"ensive 'ecause of t!e additional autotransformer and uses t!is starter for motors a'ove 8k5. Consider figures B.9  B.. In t!is control system, firstly star contactor will 'e energied. -oon after t!e transformer contactor will 'e energied. $!en after a time delay w!ile main contactor is energied t!e star contactor will 'e energied. At t!is moment, motor !ave got t!e full load. $!en after a time delay, transformer contactor also will 'e de energied. Fuse +

Emergency -to" Pus! >ff

Pus! >N

:

$7

$:

:

. $

. -

: Contactor elay

$: $imer

"S

.s

"#

$:

"M

$7 $imer

N

Figure B.9  Control Diagram of an Auto $ransformer -tarter


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U

*


5

Fuses

. ( (ain Contactor

. $ $ransformer Contactor

Auto $ransformer >ver Current elay

M

. -tar Contactor

Figure B.  Power Diagram of an Auto $ransformer -tarter


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:.7 Capa%)or Ban3" :.7.1 D!"#n

Ca"acitor 'anks are mainly installed to "rovide ca"acitive reactive com"ensation6 "ower factor correction. $!e use of ca"acitor 'anks !as increased 'ecause t!ey are relatively ine#"ensive, easy and =uick to install and can 'e de"loyed virtually anyw!ere in t!e network. Its installation !as ot!er 'eneficial effects on t!e system suc! as, im"rovement of t!e voltage at t!e load, 'etter voltage regulation. Normally in factories or ot!er !ig! "ower consuming "laces, most "ro'a'ly t!ere will 'e a consum"tion of inductive load. Inductive voltage means t!at t!ere must 'e a lagging "ower factor. In order to reduce t!e tariff  utiliation of "ower t!e "ower factor must 'e taken near to :. $!at means "ower factor angle must 'e taken to ero. $o do t!is we su""ly a ca"acitive load to com"ensate t!e inductive load. $!is is t!e system of a ca"acitor 'ank.

FigureB.;  P!ase Diagram $!e "ower factor regulator com'ines com"re!ensive o"eration wit! user/friendly control setting. It uses numerical tec!ni=ues in com"uting t!e "!ase difference 'etween t!e fundamentals of current and voltage, t!us "recise "ower factor measurement is ac!ieved even in "resence of !armonics. $!e "ower factor regulator is designed to o"timie t!e control of reactive "ower com"ensation. eactive "ower com"ensation is ac!ieved 'y measuring continuously t!e reactive "ower of t!e system


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and t!en com"ensated 'y t!e switc!ing of ca"acitor 'anks. $!e sensitivity setting o"timies t!e switc!ing s"eed. 5it! t!e in'uilt intelligent automatic switc!ing "rogram, t!e "ower factor regulator furt!er im"roves t!e switc!ing efficiency 'y reducing t!e num'er of switc!ing o"erations re=uired to ac!ieve t!e desired "ower factor. )enerator

CE0

Power Factor egulator

A :: A :7 A :? A :<

: 7 ? <

$o Contactors >f Ca"acitor 0ank

Au#iliary -u""ly

>n +oad C!angeover -witc!

$o +oad

1C Fuses

A::

A:7

A :?

A:<

A 7:

A 77

A7?

A 7<

Ca"acitor Contactors

Figure B.:8 5iring Diagram of a Ca"acitor 0ank


B8



:.7.( U"!" of HRC Fu"!"

In electrical system fuse acts as "rotection device and de"ending on a""lication different ty"e of fuse is to select. >ut of t!ese different ty"e of fuses 1C is also one of t!e ty"e and it stands for 1ig! u"ture Ca"acity[. $!is ty"e of fuses normally used w!ere some delay is acce"ta'le for "rotecting t!e system. it !as a advantage of current limiting feature. -o it is used for "rotection of contactors w!ic! may melt for !ig!er value of current. 1..C fuses acts as secondary "rotecting devices R'ack u" "rotectionS. $!is ty"e of fuses normally used w!ere some delay is acce"ta'le for "rotecting t!e system. $!at means t!is fuse will not 'urn out for a current "ulse  as a result of t!is it identifies a fault current  an inrus! current se"arately. -o t!ese fuses are used in series wit! motors  surge arresters.

:.7.4 U"!" of Capa%)or Con)a%)or"

(any customers use "ower/factor correction ca"acitors to increase t!e efficiencies of t!eir overall "ower systems. 5!en switc!ing ca"acitors in and out of t!e "ower system, t!e switc!ing device %contactor& can e#"erience initial in/rus! currents near :8# t!e nominal current. $!is !ig! current can reduce t!e life of t!e contactor. $!e Ca"acitor Contactors include early/make au#iliary contacts t!at 'ring "re/c!arge resistors into t!e circuit to !andle t!e !ig! in/rus! currents.

Figure B.::  Ca"acitor Contactors


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:.: ATS 5Au)oma)% Tran"f!r S0)%*6

$ransfer switc!es are critical com"onents of any emergency or stand'y "ower system. 5!en t!e normal %"referred& source of "ower is lost, a transfer switc! =uickly and safely s!ifts t!e load circuit from t!e normal source of "ower to t!e emergency %alternate& source of "ower. $!is "ermits critical loads to continue running wit! minimal or no outage. After t!e normal source of "ower !as 'een restored, t!e re/ transfer "rocess returns t!e load circuit to t!e normal "ower source. $ransfer switc!es are availa'le wit! different o"erational modes includingJ \ (anual \ Automatic (ost of t!e times 'ot! of a'ove are availa'le as one unit according to t!e customer re=uirements. A$- is mostly a relay logic control unit, 'ut sometimes availa'le as "rogramma'le logic control unit. $!e ty"ical control diagram of an A$- is as 'elow. $!e main items t!at are used in A$- are contactors wit! electrical  mec!anical interlocks. $wo cou"led contactors wit! mec!anical interlocks doesn3t energie at t!e same time. If one contactor is energied t!en automatically ot!er contactor will 'e de/ energied. $!at means at any moment "at! is "rovided for only one source, not t!e 'ot! of t!em. Consider figure B.::. $!e task of t!e timer $: is, to wait a given time to o'serve w!et!er t!ere is any failure again in t!e main su""ly % $o avoid continuous switc!ing in case of a 'ack to 'ack failures w!en generator runs& $7 timer is used to "rovide a delay to energie CE0 side. And $? timer is used to "rovide a delay to energie generator contactor %$!is is in case of a little time failure. $o avoid t!e starting of a generator for a little time failure&


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t r a t - l r a o n t g a i r e n e ) : 

7 .

F F > N >

7 .

: . 7  F P

: 

7 .

? $ ? $

7 e s u F

N E )

7 .

F F >

N >

: .

7 .

: .

:  7 $

7 $

:  : $ : $ : e s u F

:  F P

0 E C

Figure B.:7  $y"ical Control Diagram of A$-


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t r a t - l r a o n t g a i r e n e ) : 

7 .

F F >

7 0 P E

N >

7 .

7 . l ! c a t u i n w a ( r o o t t c e u l A e -

7  F P

? 0 P : .

< 0 P

: 

? $

7 .

? $

7 e s u F

N E )

7 .

F F > N >

: .

: 0 P E

: . l ! c a i t u n w a ( r o o t t c e u l A e -

: 

: 0 P 7 0 P

7 .

7 $

: .

t i u c r i C l o r t n o C l a u n a m ! t i w m a r g a i D l o r t n o C $ A  e r u g i F

7 $

:  : $ : $ : e s u F

:  F P

0 E C

Figure B.:?  Com"lete A$- Control Diagram


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CHAPTER ; CONCLUSION

I3ve got a good o""ortunity to !ave my first com"ulsory session of industrial training in E(P )rou" of Com"anies, Panagoda -ri +anka. E(P )rou" of Com"anies is t!e -ri +anka3s leading solution "rovider of electrical solutions wit! glo'al "resence. E(P !onored a lot of awards for its outstanding "erformance and ro'ust growt! in t!is sector. During t!is valua'le "eriod I was a'le to take so muc! of !and on e#"eriences installation and trou'les!ooting of mo'ile telecommunication e=ui"ment. And also I was a'le to !ave knowledge a'out "ro2ect !andling, electrical designing, I-> standards, IEEE regulations  store kee"ing 1ere I s!ould mention t!at I was a'le to get a s"ecial o""ortunity to work toget!er tec!nicians as well as engineers and s!are t!eir knowledge and e#"eriences. $!ose t!ings gave me a really good training as an engineering undergraduate. -ince E(P involving im"lementation of various electrical "ro2ects in -ri +anka, I3ve got muc! e#"erience in tec!ni=ues on im"lementation of a electrical "ro2ect, as I involved t!ere. $!is made me to interact wit! various industry "eo"le, not only from E(P, 'ut from some ot!er com"anies suc! as 1olcim %Pvt.& +$D, $e#tile A""arel %P*$& +$D etc. -ince t!e im"lementation of "ro2ect is going on in w!ole -ri +anka, I3ve got a c!ance to visit lot of sites in various "laces. 0y t!is I3ve got a vast knowledge not only in tec!nical and electrical sector 'ut also in management field. As well as $!e E(P staffs are very friendly and guided me a lot in t!e training. -o, it !el"s me to gain a 'etter e#"erience and work made my training valua'le and successful.


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REFERENCES

:. IEEE 5iring egulations 7. !tt"J66www.em".lk6 ?. !tt"J66www.lsis.'i6 <. !tt"J66wiki"edia.org6 B. !tt"J66www.sierraca'les.com6Product]ange/7/:.!tml @. !tt"J66www.electronics/manufacturers.com6info6electrical/com"onents6air/ circuit/'reaker.!tml


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Elect Notes

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