0% found this document useful (0 votes)
69 views42 pagesBEE Unit 4
The document discusses the essential features and components of electrical installation, focusing on protective devices like fuses, circuit breakers, and relays. It highlights the importance of these devices in isolating faulty sections of power systems, ensuring safety during overloads and short circuits. Additionally, it covers the advantages and disadvantages of fuses and miniature circuit breakers (MCBs), emphasizing their roles in protecting electrical equipment and preventing electrical shocks.
Uploaded by
gagandeep.j2716Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF or read online on Scribd
0% found this document useful (0 votes)
69 views42 pagesBEE Unit 4
The document discusses the essential features and components of electrical installation, focusing on protective devices like fuses, circuit breakers, and relays. It highlights the importance of these devices in isolating faulty sections of power systems, ensuring safety during overloads and short circuits. Additionally, it covers the advantages and disadvantages of fuses and miniature circuit breakers (MCBs), emphasizing their roles in protecting electrical equipment and preventing electrical shocks.
Uploaded by
gagandeep.j2716Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF or read online on Scribd
/ 42
OniT- 5 2.
ELECTRICAL INSTALLATION t-
SS eTCar a lnielecenca poster suitchgeaw elers to the
device ured kor suditching, Controlling and protecting the elechical
Chreuits and components
The Usentiol Ieoturs of protective dertces aves:
1 complete werabititys THs he mott Tmngortant feakune,ashich all
Ale protective deters Should have, in the power System. GE o faulk
Occurs In any part of the power System, then the protective device
Should opevate In Such a way that the faulty section gets fsolated
From the other port of the power System:
fy Absolutay disci minolfon- clear and accurate decrvimination
bekoeen the faulty Section and healthy seclfon 45 vequived +o
Ssolate “he faulty section:
Wh) Buseck operation: the Mme taken bby “the protective dete to
Asolote the faulty Section must be minimum so that other Pow ts
Of the system do nok gek damaged:
iy Provision for manuel Contyoli- Even if the prokectve device
| Can be made automatic, there should be a provision Joy mantis)
fenbre! to cowry out the necessary operations when *he aubomatk
Control teils.
Components of Sultch Geart-
The susiteh geov Comprises of wide vange of Components Whose
Primory Functions are Suiitching and nkerrupting currents
during oth normal ond faulty conditions the basic Components,
of Switch gear; switches, fuses, Chredt breakers, relays ond
othe equl pment . ee
UiSuReht the devtee which fs used + “open Or) Close can electrical
—
Catt in a mosk Conventional way fs called Suattch. Lt con
be operated at any Condition of the dreutl- The mafn disadvan
~koge of the switch is that it Connot tnkerupt the Current
Occuring due to faulty cond! Hon: the switches ove classified ov
aby and ofl swikehes based on the medium wsheve thre Contacts
| ore opened.
tit) Fuser A stmaple protective denice uted to protect A sustkching device, which Can be used +0 make
[ov wreak a cveadt manually, automa cally ov with the help of
under diflerent Condi Hons Fc) novmol ond Foulty
| vemoke control,
| condi Hons, fs enown os a drcuit breaker, In this ehp chapter,
Some of the types of Great breaker one discussed in detafl.
—* fuses A fuse fs a Short plece of wire ev metal oy thin
skvip wich 1s Inserted tn Series KO the Craik. shen hae Raoult
| current Plows through the fuse Jor a Suikclent dime, TE melts
land thus fsolates the civeust: eee
—~ Quivoble Chovacteri ste
[Tre clevivadle chowactenisties of the material used fn the fuse
to have Satis Hed pevteymance ave!
ce elem Fal.
s of fuse clement matertal
) low melting point egy Xin, lead
» Wigh Condurctiuity Cg: stlvey, Copper:
9) least ctleck 40 onicaton eqns, Silver
% atlordable eq
+) lead, Hn, copper
— Tervextent tems
The following ave the terms usbich ave sequived In fase onalys
1) Curvent yaking of fuse clement Bt 15 the omount of Current
wich the fuse clement Can Comry under. Normal operation
without over heativg oy melting: 7% depends on temperature vise
fin fuse holder, fuse-matertal and Surroundings of the fuse
WY) Bachag, ferctory ‘
ND Eusing correnti Tt Ts the minimum Curvenk at ushich the
fuse clement malts ov blows awoy and Isolatys “the heathy
Portion of the power system. Tis higher ‘thon the Cument Yating
Of fuse element:
iy Fusing factor: Gt ts the Tallo of the fusing current to the
Current wating of fuse clement ond tt value ts always greate,
Aon 4.
NY) respective Cavrents- T445 the Rms value of tne Loutt Curvent
which fs oblained by sreplocing the fuse with the Conductor of
neghigtble vesistonce
™) Gak-ofF Cuyrents- 24 is the mantmum value of faut Current
dvkeined before tre fuse clement melts.
NY bre- ovcing Hime the Hime taken to cut off the fault Current]
trom tks Commencement is Known as pre arcing time: Nily Ayeing Koger nike Hime taken te entinguish the ave atter
he pre-oweing Hime ts Known as orcing time .
ii) Tokal opevating me: Pt is the summation of Pre- arcing
and avelng time ~
ix) Breaking Capacity!-the RMS value of the manimum Prospe
CMe current which a fuse con deot ak rated woltage fs
Enown ag breaking capacity:
—* Advontoges ond Sisodvontagy, of dust
the advantage and disadvantages of fuse ave given below;
¥ Advantages
*) Cheapest form of protecton device
%) Requivs no mointenance
3) Operation of fuse ts Completely automatic
9 Easily breaks the lawge amount of fault Current
S) pollution tvee protectfon device teyrrr cou nok Create Ony
Smoke oy noise
€) suttable for over— current conditions due to tks Mnuerse current
= time chovacterist es:
3) Requives tas Hime in fsolating the faulty part of the Creu
# piSadvantages:
jo EASA
|\) Rewiring oy weplacing atuse taku a Considerable Hme
2» piscrimination between fuses connected fn series fs not
possible
}3) Co-velation of the chavacterishics of tuse with the Protected
deice fs nok altusays possible a
Shassilicotion of rasa
The general ctassitication of fuses ts shown tn Fig. 5-8
> Seattch pase unit Cs eu) +
The susttch puse unt (Spo) fs 0 low voltage Ac fuse unit
which fs uted to protect the electvical deutee or equt pment
from olidtevent toult conditions Thts due fe most Commonly
Used for tow and medium voltage applications. Rating of
SFO Varies from 3049 800 Amperes. But the making capacity,
Ot SEU goes Wigh Hl Agta. Sn general the sputs acta |
| aval lables OS 3 pole and 4 pole
Fuse |
|
De Ae
Fuses | Fuss
— oo
ugh voli Tass walla
| Fuses Fuse,
Contvielge Tex pate Pewirenble Cori deel Drepout! ster ] sutich |
ITY Pe (IPC HY eu pe diy! Type type
Hee Re Fuse | Pose Fuse
Fuse | Pusey | Fuses {| Fuses | Fuse
|
knife Blade Type
Hee Link fuse.
Bolked Ty pe
HRE Link puse
Classification of Fuse untk. SPU has the Capabitity of withstanding Ul the Foutt
Current weaches 3 mu full load Current:
g>por
Sthematte Diagram of Spo
re Consists of feveblaly rewireable fuse wlth thelr conduct
[Ing Parts. the suttch is Htted with Strong side operating
[handle uiing which the ctreutt Hh is made ov fsolat ed
from the supply: Tn this SpU,-the different contacts existing in
f€ is made up of silver plated electrolyte Copper clue to fh
dwn advan tages. the othty components costing fn the spo
is protected using the enclosure made up te of steel. Lt is
to be noted hat the enclosure fs provided, with an fntertock,
j to Prevent the opening ef the unit ushen the swlich f< fn on
Condition: ~¥ Suiitch fuse unit (SEU)? A puse ic 0 protective device
which acts quickly In abnomel condition, it blows and
disconnects the circuit from -the Supply: Thus Tk provides
Creuits protection by destaoying ikselt-
FA sustteh 16 used to isolate the cincdt trom the supply
Purposely fov vepoiy and meintmance . Generally it is
Monually Operated:
¥ A unib which tonsists of the combinations of fuse and
Switch together fs Called switch fuse unit. TEIS shown
‘pig. 21.
govich
He ly
Su ? | bout
oo
~o tl
cus
Figr B.a-1 sutteh fuse unit.
K the advantage of Such suitch use unit ave,
4) he number of joints in the Circuit get reduced:
ti) Duc to compact Construction, lus Space is crequived
i) Baty Som handling point of wie:
* Mintartuve clreuik Breaker (meg):
i A miniature clratt breaker 1S an eleckvomethanical deutee
which mates and breaks the eivcuit in normal operation and
disconnects the ciwadk under the abnormal condition when
Currvent enceeds a preck value. MCB fs abigh fault Capacily Current lemiting , tip dre,
automatic suiting device with thermal and magnetic
operation to prowide protection againsk overload and Shovt
Creu t-
FA fs Mecessory 40 use MCB because of its following feature
Tks operation ts very fast and opens in las than one milli
- Second.
3) Ko dvipping civeule is wecessany and the operation is
| auto matte.
3) prowides protection against overload and short dcuit
without moise , Smoke ov Flame:
A) TE cam be week very quickly after covvecting the fault,
| Suse ty swikeltng o button: No wewtring ts equine:
[STE tan wok be veetosed TF Faulk persists:
| eevee wnechanical ike fs upto or more thon one lakh operat
sing cyele-
HF tlence now a doys MBs ove used vathey than vewivatle
Suse. ,
X Generally Mews ave vated for arc voltage of 940v Foy single
phase, 415 V fow three phase oy adov die. The curvent wating
anoilable {5 from osA to 634. Mt is available as single
pole (sp), Buble pole CoP), Twi pple pole (TP) with shovt
Cineutt breaking capacity trom ita to Loka with a vated
Lrequency:
view of MCB ond its practi cal
He A typtcol
. 6B, below,
ap peavance fs shown in Fig &
Lad
Reloy Cael
Cks
Egualent Circuito COS
Compass MCB with Hater
Sino!
ue
Fuse
Lood
4 yoo
KA om ne
~~ Kinsulattion
“deinsil 109 ptmeted element
} Basie dragrera, of iMcB’y
MB
whe operation of fuse (5
highly dependent on selected
ob Als proper rating Dt fuse
Jwire fs nok selected properly}
Aken tk vaults tn nen
operation of fuse even in
case of Short Chreuik
the visk of Be and Prevents
McB instantly disconnects the
Supply aubomatt tally in the
euent of Short circuit (ov)
overloads TE thus eliminates
damage to wiring Systern-
Ft Ae fuse esive atker
operation ts replaced with
ao newer ont but go loase
den Tt mnay be dangerous.
Heo 4o veplace a blown
fuse Sn burton between
Restarting power supply otter
Loipping due 40 overload ov
Short 4s cosy
A |
:
|
|
the schematic of ELCB is
lhe _leept ready
4.
—*
Gevvent Comrying points 4s |
dangerous Specially in dort,
| During sreplacement of fuse
J wive, the emack side of
fuse uive may not be
available: Also dow rveplaceren
jakit of hand tools has to
a eS
No maintenance and repairs
is mrequive tow MCB- the
distribution System employing
Men provides satisfactory
poration and lasts tor years:
[The board em ploying Fuse
I" not Compact’
‘The board employing MCBs
give beautiful loote os ft fe
Compact and elegant
Earth Leakage cheestt
as
Coment
Transtonmes
Breaker CeLcs)
Shown in the pig Q.S1
er
1 sali
! Amor
‘ Tes
| Raistr Pei
| Pricting — utay
! cl
'
' i Fault to
Par ree] MY} corth due fe
eigt?™ va leakage ov
connteled Ty touch’ ng
surely |! 40 olive
1 terre nod
| Faclosume of
dhe peice @
As shown in the Fig: G5) ELCB Consists of & Small Current
branstormer sumrounding Vive and neutral wire. the seconda
“TY winding of Curmnt kvanslormer 4s connected to veloy
Greuit which tan tip the civeuit breaker which 7s Connected
in Ake cuit:
undey normal CondiKions, the Curmnt inline and neubral
Conductor 1s some othe nek Current C1p-Tnt) Slowing through
Whe Cove is devo. Eventually There usill mot be any production of
flum in the Cove and no induced emf. So the breaker dow ||
nok dvip:
ATE thee ts a fautk dure to lealeage from Vive wire 40 casth|
oy & Person by mistake touching to the live terminal then |
[Ale nek Current trrough to the Cove will no longer eremain |
as Bere but equal to Sp-Sy or Ty which will set Ap Hus
and emf fn GoTo as per the Prebent valus, Ake unbalance fn
Current fs detected by CT. ond relay coil fs ener gided which
will give tripping signal tow the circuit breaker As eT
operates with low value of current, the core musk be very
permeable at low flux densi
$ahus ELCR provides protection againsk cleekye shocte when
© pewson tome tn contact with live parts vaulting tn
Blow of Current vom body +o canth.
HA properly connected BLCB detecls such small currents in
milliamperes dewing to cavth Ahyough human body or corth
wire ond breaks the Civtuit to weduce ake aisk of
clechocutinn to humans: There ave Certain situatlons where leakge Current can flow
Adwough “the metal bodicg of appliances, when person touches to
Such appliancy. Thur person Con get a shock:
% Similarly theve fs wisk of fre duc to such cavth leakage
Currents
¥ Thur a protective dewlee is necessary which Say Can Sense
Small leakage Current and disconnect “the caveat Lrom Supply.
Such a device Ty Called earth leakage civeuit breakers CELCB)-
U provider protection to a human against the eleckic shock-
2) pekeels very Smal! leakage Currents |
2) Reduces the Risk of fre due to hok Spobs- |
4) Saver elechical energy duc to leateage-
5) Energy conservation Con be ochitved:
—¥ Moulded Case Civcutt Breaker (Mees):
Meuldee oS Oe
% Mcce ts Similar to MCB but used when the load Curvenbs
enceed the Capabilities of Mcp Skis used toy civeulls having
Curvent wanges trom 634 to $0008:
Magrelic elemert
pen
evel ata
m2 line T GUS working 4s based on thermal mechani gms Tk has a
bimetallic contact which emtpands and tontracts when There
Ore changes tn demperature » under normal condition, the
Contacts ave closed allowing current ‘to pass- under OVGr
Toad ov short evcait condi fon, Current etceeds THs Safe value
Due to Alds, heat fs gentrated ond the conkacts ore opened
to interrupt the cincuit:
F DUC tothe InterapKon of high current , there ff arc
formations lence fn MCC there ave arc entingutshers eshfch
Suppras “the arc:
Fthere (5 a disconnection switch, with he help of which, the
MECB Con be operated manually
¥ prakee practically Tt has adjustable tip settings and hence
GX can be used for Wigh Curvent applications.
HTL Con be easily vat ater the fault wectiKeation. thus it
Provides operational Safely and tonverfience
H Ali Ahe Operating parts of MCCB ave Covered within o plastic
moulded housing made in two Malues the 90 halves ave joined.
together to form “the whole structure:
ik vhe baste diflevence between Mee and HEC ‘4 he Convent
erating - ence MCcBs ave used fov industial and Commercial
applications such at main feeder protection, generator and
motor protection, tapacitey bank Protection, welding applicator
and applitations which requive adjustable trip setting
H MCC Bs ave Used for high Current profecton Such as,
1) Gteneratoy protection
2) Molin feeder protection 8) motor protection
4) Capacitor bank protection
5) Llelding appli cations
©) Appiicalions which need adjustable Current trip setting.
—* Types of wivesi—
) vuleanised Sudic Rubber wives (v-t-e)
a) tab Tyre sheathed wives Cots)
8) poly wing) chloride wives Creve)
4) plexible wive-
H The valour type of wis which ave wed for various woivining
Schimus ore
H)slaleueae, Selle "oper: ive EER
ATMs lype of Were consists Hinned conductor Coated with rubbe
Swsulation this is further Covered with protective cotton and
bitumen Compound and nally Huished with wor Wis makes
Te moisture and heat vuistant hue avd always single Cove
wives Though ave Covered with a cotton tayer Tk has
Aendency te absorb moisture and hence varcly uted, nowa days.
conductor
Colton Cie wire) Deb Tye sheathed wives (eT)
Gn Anis type, ordinary mabey ‘insulated Conductors art
Provided with an additional tough wubber Sheath » the wire
Fs ato Known a Tough Rubber sheathed (TRS) wire «SE
provida padiVional {nsulation and along with -thak a protection
a thue
against moisture, cherieal fumes and weer end Hays The
. cove
cue alto ovatloblt in single Cove, double core Gnd thoes
Navies:
=
t Conductor
Additionol
tough webber
5 poly viny) chloride wives (eae) :-
Mise cre most tommonly used wine Thue have Conductors
wih pee ingulation. Prue has following chorackenisties!
1) Sk As Rombygroscopic and moisture prook-
3) DEAS tough and hence durable:
2) Ruistank +o Corrosion:
) DEAS chemically Inet
8) as tk te tough 20 addi Konal torte As nok wequived:
The only Afsaduantogy 4s, it softens ot highs temperature and
hence Vk avoided where emtreme of temperature may occur:
eq-“w heating applionces
‘eis 4) plexible whresi-
Phuc ave used very Commonly in domestic wiring oy fre foy
wiring oy for wiring of temporary nature:
HAE Consist of HOO Seperately insulated Stranded Conductors.
The Insulaton 45 mostly vubber. more Commonly avai lable
in parallel (ov) twisted wins.
# vduc to its flewible nature, the handling of thuc iwiere
become very caty:
Twisted toin flenible wire-
ey of cables:-
% Ay underground cable 4s delined as the groups of
individually “nsulated one ov move Conductors which 1s
put together ond Pnally prowided with number of layers
pl ‘insulation 49 give proper mechanical support
HMhe ig. Bie! Shows -the general constriction of a cable
The cable shows is single toncductoy underground Cable—
ks vonious Parts ave, WZ 73 Armouring
— bedding
|] — Lead sheath
<— Trsulation
<—— cond ctor
Fig: OlIGteneral Construction of a cable:
1) Qnducler ©) Cove! this scelion consists of Single conductor
Oy move than ont Conductor. ‘the Conductors ave also called
Cores. A Cable with three conductors is Called three cove cable -
“he Conductors uted ave aluminium ov annedled Copper: the
Conductors are stranded Conductors Wn ordey to prouide
Slewibility to the Cable.
9) Fnsulation' Each tonducloy sy tore 4 covered by “nsulalin
ok proper ALicklas othe Commonly used insulating matewiall
awe Varnished Cambric, vulcaniged bitumen and Impregna
“led paper
3) Metallic Sheath: the ‘insulated Conductors are ieovered by
lead Sheath or aluminium Sheath. this provides the mecha
nical protection but mainly rutricts moisture and other
gas to each to the ‘nsutation- 4) Beddings the metallfe sheath ts covercd by another layer
bedding + the bedding consists of paper tape
called,
Levials [fee jute skrands
Compounded with a Rbrous mo!
ov hessian tape: ‘The purpose of bedding is to protect “the
matallic sheath from corrosion ond Yrem mechani col Injury
srulling duc to aymouving:
5) Armourings- “this layer consisks of the layer of golaviaed
Skeet wives which provide protection tothe Calle trem “the
mechanical Mnjary:
6) Sevvingy “the ask layer alvove the armouring is Serving, Pt
fetal Bie Jute cloth which protects
Ts a Aayey of brows ma!
sthe armouring Prom the akmos phevic Condé Fons:
Fothe typeof cable 4s basically decided on the voltage level for
which This manufrackured and the materfat used choy the
{nsulation Such as Cotton, paper, wubber etc
Hk Tased on Noltage level, He worieus ty PA of cables ore,
Ws Low Tension CLT) cables used Jor the voltage levels upto
6.6 Ky.
ae Medium fens ton Cables Used for WEY level andare
Called belted cable
3 AG, f .
‘High: ckension Cables used for Gailey ond 33k tevels:
HThuse ove Screened type tables! and! Juyther’ classified as:
i) A Aype corbler and thy sl- Cables ie, Separate! lead | Screened
Cables: 4 Exbyra hi +
igh 4
: gh tension cables!- uted
oe for woltage levels move
‘ oe : mas Oe Prasuxe Cables which ove fus & "
assifed ass 41) oil filled Cobles and sir Glas -
\ pressure Cables.
Khe MH
9 Gt s
hows the consbructional detoils of Vari
ous
Aypes of cables
rots Or aie
seein
Srapregnat’d
Paper
(@) Sindle
Singh Core Li Ts Cable
dead sheeth
conductor
paper insulation
juke tling
paper bel
geet
cot
* =
pan 3 i one
t guckied
, voult
we
x
oe
pattie
a (C) H- type Cable:
gure” geod hor
a od
on 4
opeutation
Sepovate
: lead Sheath
Dawg,
Lotton Lape
(d) sete Aype cable-
serving
Head sheath.
Or vi
i \ duct
\ Conductor
paper ingulation-
arhangulon
shape
conductor
W) Gtat presuve cable:
Fig- 813-1 Construction of various typy of Cables. ¥ Based on the Cores, he Vorrows -kypes of Cable arc,
WY) Single cove hy Tue tdve ond AW) three dove cable:
¥ he advantages ave,
We Regquive las maintenance:
then} )
The voltage drop is leas than overhead tins
&
Nok afbected by lightving , Storms and other weather
Conditions.
As Beauly of towne and ke gels matin kai ned
S* possivitity of accidents Vs lus:
S possibility of Boutls eles
* the \imtfattons ove,
\ Tikal cost is very Wigh:
A the Side ig move hence Anskalletion 4s difficult and
Cos ty
3 Tnsulation’ cost is high.
4 Long distance transmission is not possible:
¥ Foy diskwibution of power tn town and tits which ove
Abickly populated oreas
* Lov Providing power to ores wheve overhead Nines obve
nok perwitted-
¥ For elechil cation of oveas, wheve joeauly Ys) required to
be mointained Such as gardens, holt , cducistional
buildings eke,
¥ For supplyms mining machind an mining industries
Ty Fused dn power netusovles: “
H Specials cables ave used fin Suitch control) veloy and
nslvumen tation panels of power switch gears voy!
—* Tnportance of Eoxting
¥F The Connection of cleclrical machinery to the general mas
OF conth, with a Conductiog material of wery low
vesiskance 1s called “eoxthing. or" grounding
¥ Consider a machine which 2 not eonthed: This operated
ak Supply voltage v-
¥ IL A person touchy to the ot part of the machine then
os long as insulating of Ahe machine is perfect, person will,
| mot get a shock. the ingulaMion vaistonce of perfect insula
~Hon is Infinite:
| Buk GF Ahere is some faulk andi fnsulation becomes wtak
ov if one of the windings is touching tothe Covey of the
machine then insulation wesistance becomes devo. TH Person
| touches to Such a machine, Current Jlows Hough -the teady,
ruistance 14 small, Current through the body 48! high' so
Ahak dhe person receiuy a shock!
# To avoid such o sftuotion, -Hhe body of the machine 45
Connected to the cdvth with o very low vesistance +» this ts
| Called earthing.
¥ IF machine is carthed an Person touchy to a faulty
machine then body resistance ‘and’ covtting aeistance’ ———
‘appears to hem, parallel
Was carthing yeistance ts very small Alan the creas tonce
bt Ake body hence almost entire Current flows through
towthing connection:
thus current Ihrough dhe body of the perton Ts almost
Ae and purson dotsnot veceive any shock!
Psirilawly due to coothing , the tall buildings, structures and
| other mothine ove protected from Wigh voltage tn over 9
cheod Vines and the otmosphene lightening at high voltage
tnd lightening at high Voltage and Lightening, qets
discherging to cavth through carthing connection:
| F pac to canthing the ine voltage is maintoined at constant!
Nalue-
¥Hence eanthing 4s neeessary. for all domestic appliances,
machines, buildings and cluctures, equipments power Station!
ats ,
Y plate carting:
>») phpe earthing:
Rod carting:
4) Eonthing Through woter main
3) Horizontal SH earthing: |
bat ees earth Connection Is Provided with 4ne help of
Copper plac ov Gualvaniaed Son (if) plate, he coppey
Plate. side is
Side
Socm¥60em ¥ 3.1e mm whle Gud. plate
4s not lasthan 6ocmxtocm x $ 3mm s The GoT plates ore Commonly used now-a-doyt. the plate is embedded
B meters (to fect) into the grounds the plate 4s kept
with ats face \terkical:
Fhe plate 1s Survounded by the alternate layer of coke
end
Salt Foy minimum diclnus of obouk 156m. the
Covth uive 1s draw though Gt-3. pipe and ts perfectly
of copper plate and must boot galvanized Tron for
| olicd to Whe earth plate the nuts and wolks must be
|
|
| Ged. plate.
F The comth Kad used musk be Gel wire ov Gel ship
of Suthicient cross—secfional area +0 camy dhe foutt
| Current Safely. the corth wire is dvawn through Gul. pipe
| of tamen diameter, at abouk focm below the ground. :
Hohe GA. Pipe Is MAted with a funnel on the top- Bn order
jt have an effective earthing » Salt waker is poured periods
[TEatly Ahrough tie funnel:
[¥ the earthing efficiency ,Tnertases with the tereases lof!
the plate avea and depth of embedding Tt the esis vity
Jot Ake soil is high, then SF Ss necessary to embed the plate
| teMically at a greathey depth into Ant ground.
Rothe only dtradvantage of this mithed |7s that Hae discon
-Mnuity of the covth ustre drom athe carthing plate belo’
the ecorth Can mok be observed physically. This may Cause
misleading and may reult Inte heavy dosses undty fault
Condi tions. - 1
HK the Schematic Orvrangement of plate cavtking 4s shown
in Ahe Pig. Qe)
30cm x 300m.
T~ layer of coke and salt
boom x G0tm x Br SmmM
GTi plate:
Form
Fig: Gl81 plate earthing:
@Pipe casting “7 "
¥ Dn ts method of eanthing a Gif. pipe of 3tmm diamele
and 2 meker (4 fect) length ts embedded verKeally inte
Me ground «this pipe cicts as om earth electrode the
depth depends on the Condition of the scl
Rothe cavth Wires ane fostented to the top section of the
vipe above the ground tevel with nut and bolts: H The pk area around the pipe ty filled with salt and
Coal mixture for Improving the condition of tht soil and
covtking chfidienty the schematic arrangement of pipe
earthing syikem 4s shown in the pig. Q.t9-1
HR The Contact surface of Gul pipe with the soils move as
Compared to the plate due to ibs teycular section ond. hence
ton handle heavier eateage current Por the Same electrode
Side:
1
Cement concrete |
Oty hm
[etre
diame ley
amen dfamelor
Mata G5 pipe
Alkernate layers
of charcoal and salt
Fig: Q.191 pipe earthing: —$———
¥ According to Tnaian standard, dle pige should bE placed at
© depth Of 445m, Pmpregnating the Coke with Salk decreases
Ake cavth nesistance: Grenevally alternate lagers of salt and cots
axe used Joy beak routs:
FIn summer seaton, soil become dry. Jn such Case gatt water
Ms poured Ahwough the funnel connected to the main Grr.
| Pipe Alwough lame diameter pipe This keeps the soil wet
Rhe cavth wire are connect. 40 dhe Gif. pipe aboue the
Ground level and Can be physically Snspected from Hime to
Aime these Connections can be checked for performing
Con Rutty Labs. this is He tmportant eudvontage of Pipe
Leorlling Over dhe plate carling the tovth lead used must
be Gud. wive of sutficient Cross-sectional avea to Carry
Joutl Curent Safely: Tt should not be las thon electical.
| equivalent of copper conductor of 19/49 mmr cross —Sectiono
raven,
¥ The only, Ais advantage of pipe carting Is that the
embedded pipe length has to be Incveased Subfictently in
Case Abe sot) Specific risisMvity 7s of Wigh evden. his
Ancreases “Whe encavadion work and hence Increased Cost An
ordinany Soil Conctilion Whe vange of the earth vetistance
Should be 9 to 5 ohms
|¥ Sm the places where wacky soil earth bed extStS5 hori Senta!
Ship conthing 45 used this 1s suttable OS Soil excavotion
rvequived fow plate on pipe covtting is AIHTcult “in such
Places. por such Soils eovth mesistomce Ts between S40 Sohms Type of battery
Applications:
dead acid battoy! Sn automobilu for starting “and
Nickd ~ Cadmium
ead tery
NUM battery
(uvekel metal hydrid) and laptops, digital comevas,) cleckron
[Vighking, battery electric vehiclts, backup
bpevalions [ilee vail road Signals, dix
fvallic Control and critical systems
fin Sub marinus, for lights and fons in
_treins tte
Gy matlways for Lighting and atv
Condi Honing systems, for starting
enginu and provide emergency power
Supply Ga milli tary rere planes and
heli top ters, Tn movie cameras and
photetlash, fn tlecbic Shoser, Varies
pk Cordless clectronte devices Cte
Cellular phones, portable computers.
toys, providing emergency supply to
Namo electronic Instruments eke.
Lithium battery
( Lithium Yon)
Congumev products Such of CamCorders,
Calculators, electric razors, medical
equd pmenkats, Portable radios, tn
traction:
SMP battery[ seated
maint nance Prec}
ups systems, Kele Com muni cations. ¢q uip.
ments, Fae alarms and Security Systems|
office automation equipments sete. coe
q
PK dm portent chara cherisies Pov Batteriat The axious maaad
Chavackert shes Soy battens ove.
andicatedi oon a battery depending]
1, Nomi nal voltage Th ts
gris the Open
bn Ake amount ok cells connected aan Bech
Chaves volkage Of a battery:
+ Baltoy topackty Wd bakery WHC Gier Ib 4s speeitied. in
ampere - hours Cah) .
ry which o baktery Con
HF Me indi cater the amount of eden
AAU ais volkage
Supply at the specitied discharge ered
Gott: to 0 Specited value:
# Mathematically product oF discharge current (2p) In amper
hours Kil volkage
ama the Hine for discharge (To)
Balls toa spedied value is the Copodtty pt a battery
To (Ah)
Lo
Battery capacily
3 Specie gravity of clectooty ker More the Specify met
pk cleckrolyte, more fs Mae battery Capacity Ik deci
Gaternal resistance of & bakeeny:
Ae Specific energy The attery Capacity empreased Tn
watt hour per Bg weight 4s Called Specie, energy. St
4s also called gravimetric “energy clens?ly of a battery.
5 A Alice
Electvical chonacteristich? “Thue chawacteristies ‘nebude , thd
changing and discharging curves tov a battery: Deis Ae grap
of Aevminal voltage against chorging oy dSscharging Kime in
hours at nowmal wate. The pig: Q:al-] shows such curred for” | ® Sp typical battery, Prom the given Charging “ert
Aischar ging curves, the Hime of discharge tov a specified
Noliage lewel con be obtoined:
(& Batley eftelney- Ih ts defined at the vatio of the oukpub
during dschavging to the input mequived during charging , to
sreqain the oviginal state of dhe battery: |
|¥ Tk 4s Commonly Called ampere hour efffcfency oy quantity
% Amp—hours on dischorge
An =
|
etlickency and denoted 8 % py" |
Amp - hours on charge |
Nees ‘current & Time on discharge «00
ah =] aarent x Time on chorgt »
HR for lead acid battery ; Gk is about Sof 40 VOT:
Ethe total cleelvical chery consumption Ts the addition of
clectical energy Consumption ot Vaxtous domestic appliances ov
fn dustrial mackinery:
RTO caltulate re consumption of an cleckical appliance,
Goltouing Yactors ane requived ,
'
Ve capacity of electical appliance ‘in watts:
fs Numbers of hours for which appliances fs fn we inone day.
3. Humbers of days pey month oy years as por the required
energy Calculation -
# Mathematically energy consumption of an appliance 4s given
by, \ @
Capacity of fen, a “oe of sf)
appliance én ours] day, days | month
ee Ce kh per month
ple 1 1
H whe division of tooo is to etpres erergy consumption in KLth,
fee, units i unit = eth].
% Addivion of Such energy Consumplions of atl the appliancss,
okal energy Consumpkions per month, tan be obtdined: ‘
F Buk prackcally an energy meker is ‘installed which divéctly
measur the total energy Consumption of A howe ov Krdus bry:
rhs Jo praleal energy Consumption caleatation we need,
I+ Energy meter weading at the start of counting period
as Bnergy meter reading ok the wd - of counting period:
be ptumber of days fm a ounting pened wlfich 1s generally
a month
se Tokal. energy consumption pey month = Pinal reading in
eidh after a month - Dnitlel meading in Mh
To Bnd The consumption fy one year the energy Consumption
Por day ts multiplicd by 365 dogs:
* Fox calculating. energy savings use
Energy saving Ses n Energy Concumplion |_|’ Sera Consus a
CeWh ytor) Perday in previous dey year} Lier Current ye
F By Enowing energy Consumption of cach appliance and 4
s
‘replacing bulbs by lower usartage -bulbs if possible, Saving “in
thergy Can be be “achieved: —
—¥ Power fatler tmprovement and battey backup
Gn ac ered The cosine of Angle belween volkage and
Current 4s Called power dactoy. Th 1s denoted ds cos ¢- /
ME mhe active power consumption in arcs ives Vs the product
Of Woltage and the Component of the Current which Ts hn
Phase with the voltage which fs decided by the cosd-
K mhus -the power factor affects the active pewer Consumption
of the civetl. :
Khe power dvfangle for Hine Ahvee phase cireult which Te oF
shoum in the fig @.a3.1-St Ts also called as EVA Ayfangle,
PF he posty doctor can be obbained as the watio of activ
| Power 40 apparent geusey
[ETE Ahe lagging wveactive power component 1g shown downward,
Wen dhe tading reactive power Com ponent is shoon upwards:
Ackive power
prarent power
B= Gwj, sind coed =
i Reactive
Keer SS Pours
pouty
So TY lagging meackive power 1S more, F ull bE move and coss
will be lus. puc to awis 40 Supply Same omounk af active
Power the Crrent drawn ‘by the eivcutd will be more whichis
nok duivadle-
Gf an additional load drawing leading weackive power is
Connected in Farattel usith the oviginal Toad clhen leading
reactive power is In opposite cMivection to Lagging reactive
Power soit partly neutvolisa the cffeed of lagging veactive @
MEAUCH Je Current required “to Supply Same amount of aclue
Powers puc to this, d reduces and cos# Increases- this
Power will reduce:
® So lagging weactive powty tie to lower the power Jactor
While the leading «reactive power Increases ‘the power factey.
a y po
the motn! cause of tow power factor is inductive leads:
Such Joads Inclidt,
\’ Transformers (i) Trawelion motors (3 phase and single Phase)
fii, Snduction qenevotors hy Dometic appliances and Nigh Ying
lead Ws High intensity discharge Ighting Wir Gndushfal ‘induct
~on fumacy ee
AN. Ghee loads constitute a major portion of Ake power
Congum phon bile leading pouty actor loads art very us in
mumoct”
Ftlence the overall power factor 4s very low
# she various problems of {ow power Rackoy erty
Ve Louty 43 Ake power factor, Kighey is the load tasrent forthe
Same amount of achive power
9. The Conductor side depends on Whe Cucrenk «POY Wighey Current
greater Conductor side hs required:
3 Higher Conductor side Ancreases the cost of the System:
4 Large current Causes move Copper Losses Cire). This wautts
‘into poor cf ficiency:
G- Large current Causa large vollage drop (12) tn trons |
cynission Timu, alternators and trans formers. This reduces
available at the Supply ends this raul’
Ahe voltage 'Vinte pooy mgulation of the vartous devices
(F Power Factor Improvement ! the baste requirement te Impror}
Power actor is the leading reactive power loads. one of
Such loads 7s Capacitors:
Arthas by Connecting Capacitor 4 parallel with the lagging
Power factor load, the overall power factor Can be improved
% Comsidey a lagging powey teed factor load as Shove Yn the
| Fig: G-24-1 Ca) sthe Corresponding phasor diagram is Shown '
| “he Fig. @.9441 hb):
ba ek Tbe she Current draton at a lagging power factor angle
of ¢,.
K To improve the power factor, a Capacitor 1s Connected across
he load as shown ‘in the Fig: Or 34-2
& | Lagging
FI} pts
load:
|
@
Fig 6+24-|
# the Capacitor tatd a leading Current 44, which leads
\rlkoge wv by en angle ot Ad as shown In the Fig-A-a4-9@)/
His \eading Component of current 9, bnfes te neubralige the
Nagging etfeck of G,- tence the vesutkant Current becom OS Shown in the
*9
Fig 0.94. 9tb).
Fb tan be Seen thot dhe effective power factor angle become
Fwhich 48 las than dy Hence Cos $s more “than Coss) thus
Ahere Is Sm provement tin the power Factoy of the system.
Ftthe devices generally used to Gmprove the power factor ore,
Y Bonk of Skate Capacitors,
2 Synchronous Condensers,
3) phase advancers.
it ped
| Coss > cos 9,
vob ohe op8, Se 1 fh
| dead | !
! ! re ¥ cy
| gt a
4 a
|
—* Battery Backuph A battery backup device 4s an electronic
device that Supplies Secondony power in the absence of he
moin Pour Tk can also protect electronic hardwore from power
SPiKO ond Fluctuations.
athe main battery backup device which ts) Commonly used 4s
Called uninterruptible power Supply [ups].
Meee "BE uper
{Most of the Systems operate on a-c. Supply Thus ac. Supply
Joilure Causes Periodical Stoppage of the various Systems. la Mosk of the modern Systems use tempukeys and ona
_ : vou!
© cusoTs: Any, Ankerruption in the powey supply may ye
‘ Gneiheck
Anko Ale las of the work and may make system in
Ne :
layin
3: Many Smportank places Wes hespitals, temples plasms
stheiy
grounds, banks ele, wequire continuous Supply for wet
edKckent operation:
A fons , battery
¥ To oncid all thee aduerse and Strious Srkuction.
i f by using Ups:
| bacleup 45 necessary + Tt is provided by wing
|
an ups
the Figs @.961 shows a very basic block diagram of 9” Up
which 5 ustng tec power sources, controlled by a siottch-
ups
etd
cul put
Supply
Battery
Fig. Qe2G] Basic Concept of Ups
F the ups is desiued So-that there 44 one Soumce of power,
sede undey nowmal Conditfons , Known at,
Primary power Source Cusuatty + ¢. mains)
Nhat come,
Tis
and other gowce,
Af the primary source 5 HA srupted:
Omother sources Is Called. the Sécondory power source
Cusually battery). a sutch
3¥ changes trom PHmmany
‘inte actéon
Ss used as a controlling device.
Sources, to Secondary when it @
detects that the primary Source has foiled LE automokica
ally Switches back from the Secondary Power Sourcd +o
Lhe primary when sk is detected that the prtiminny amerte
has wetumned to Rowmal:
B othe power available From mains 1s ac. ail batteries
Provide dice Hence fn UPS tere Ops there Is circusty to
Convert Are todee Foy baitey charging called a converter.
Similanty there 1s a device Converting dic. from battery to
ac: as requived by the load. This ts called an inverter:
“hue are important Components of any ups:
HE The hoo types of Ups aves yon line Ops 27 OFF hme Ups-
Hthe ON ime ups 1s also called Avue Ups. Sn Alas Ayre of
Ups, Ahere ore woo powey Sources and a dvansfer switch
Anat selects belween them the tmportant Jeature of “this
vps is that ik Use the battery as TES primary pow’ Source
4k Secondary power Source
and arcemains power as
xe The Pig + @.99-1 shows -the bleck Schematic of oat Tine wps.
It under normal operations, the ops TS vunning oFF the battery
while the Ime power runs the batley charger . The vectifier
Convers arcs mating to dsc. and Inverter Converts dic tore and
43 iven tothe load thus there ore Oo Conversions In
Alas type of ops hence “k 1S Called double Conversion On Fine
UPS. As inverter ig always Working In nowmal Condi Bons, it,
1s also called Mnverter prcherred The normal operation
path tE shown by dart: linen the Fig: 819499)
FT} the power gow out, the Inverter and load, Continua to
work on the battery. Only the battery charger foils in Such © tase Ths path 4f shonin The Fig) G-99:2 The time!
vequived oy Ups to Lyanstor on battery is called transtey
Mune wWiich 1s fmportant Chore cked ses of ups’ But Vn On
ine
pile protedor gi tex
wee
ee ;
|, To
| lood:
Tronstex
a fangs th farts Edt *
Bones ® Vet sutich
OO Galler 5
fj oeereton exe Spvenk
| goth Chonger | (AR j
| on |
weetitien :
~ Balkeny ' !
Fig: 8193-1 Block Schematic of OM Inc Ups:
te
7] toa)
gasitch
Gn enter
= Bolkey
Fig 6.92-2 path when ac: mains foils:
ups there is 0 Avan fev Hine ond Ups instantly switchy
over to the battery when mains foils the load Keeps running
without ony -Find of fnkevmapkion: only belkery Starks run
down as there 45 no Line power to charge it- HK wow Lek US understand the 4mportance of the Secondary
Power path: Tt “is Shown dashed in’ the Fig: B-99-2- TE come
tmko “he achon if the muerte foils. the transfer susitch
automatically changes trom posifion | te position a, to Suottch the
load ON arc. mainS. The Spike protector protects “the load
| from position! to position 2, to switch the load on ae mains,
The Spike protector protects Ahe load from Surqu In line
Power and filters them out- Jn his switch over, transfer time
is Important which Should be as small as’ possible. But in
Practice, main power failures are much more common than
he ‘Saver ter failure
% The Important advantoge ofthis ups 15,79 howmal concition
the double Conversion process 4otally isolates the oukpul power
From he fnput powers Any Severe Change in main power a tect
Ae battay Charger and not the output loads:
Khe Gmportant Consideration wile daigring ON tine ops fs
ex) and inverter ave manning & 4 hour
Hot converter Crectit
ks must be
a day and go on: ‘Hence quatity of the tomponen
Superior to avvid ‘the Inverter failure condi Hons ithe sige and
Coste of ON Tre OPS Ts more than other typ of Ups:
KA port from tost, another disadvantage of ON Mme ops
is
inc Hfeiency AU The power reaching Ao the lood is
Converecdh trom arc tod-c ond back to are thus mech of
Ane power fs dissipated as heat. this is happening all the
Aime and not just when mains Salls- > --—
the applications of ON Vine Ups ave,
1) Nekwork gateoays and bridge:
components Such aS
2) Tele communications systems:
3) voice maf! and E-mails systers:
4) Tuk and diagnostic equipments:
5) Nekwork Servers: ;
©) Othe critical eleckronic equipments
the On Vine Ups are avatlables from Sooo VA Upto hundecds
of Yhousands of VA Capacity:
[kthe Off Une ups 7s also Called Stand by UPS: Go this type
of Ups the Primony power Source fs the mains power and
the Secondary power goerces 4s the battery
Normal
operation spire protector — efiter Tran shew
weil switch
Ace a
cing
——{4| ft} —pa. Tot bad:
lz
a a only
g Bottery Qrverker then
chat
“a Power
‘ em] faits
Coninuous I
chonging = Batkeny
Fig: B-24.1 Block Schematic Of OFF line ups:
PH the Fig. 8.99.1 shows the blocks Schemakics of OFF Kine ops
% Tris ups the battery and fnvertey are normally not
supplying power to the loads the battery Charger is using the
Vine poroer to charge the battery but battery ond Inverter
are waiting Im Standby mode 4 they ave needed: Hence [Ake ups {5 called stondby ups Ag main Vine is Primary =
| Power source, Lis also called Vine pret tryed Ops:
IK The Spike protector and Biker ave used to Filkey the ne
noise and surges and to protect the loads trom Severs
mains Conditions +
*® then the are. moins powers gow out , the Lranster sui teh y
AekeCS TE and automatically switchs from position t tea.
| aus baitey Starts supplying the Load through inverter: This
[4s shown im the pig-G-29-2 this ath 1s similor te that “t
ON Vines
= Boltery
Ptg* 889-9 path Lihen asc mains foils.
UPS the battery neo sharks aun dwown as there is no
Tine poroey te charge Ite
H ps seen, every OFF Vine Ups arequines a Limite time to
dyanster Hae Susttch from position (to 2 and such o transla,
Can nok happen Instantly: This me is Called transtey time
cv suttch Himes The units sup plied Prom ups have Some
heldup me means they Com held the power fov Lraction
OL Seconds when mains dails- leey points. The tyanstey Hime of Ups must be much les than,
we holdup me:
¥ Thos Lanste Hime 4s an Important consideration In Case
Of crifical joads.the Avanstey Hime is In the rrange of mito
Bs
UX The Vavious ‘applfcations of OFF Mine’ Ups ave,
1) Work stations
| 3)
ond peripherals:
Modems:
3) OlMce and heme Peg,
4) Small daktop hubs
5) Small businus centers
9) Suilches
S:No Parameley Ont Line UPS. OFF Mine _ups-
Ve operations — Batkery 43 the Primary | Asc. mains 15 the
|
[Source ond aC mains is | Primary source and
| Sctondomy power Source battery 4s the secondary
| Power Source
| 8 |Gsotaion / complete “isolation between] nto