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APPRECIATlOIIOREII81mBS;IT''

LESSON 4.2METER TYPES AND CLASSIFICATIONS

LESSONOVERVIEW

DESCRIPTION

This lesson overviews the operation and maintenance of different types of meters usedin power transmission and distribution systems.

OBJECTIVES

Upon completion of this lesson, the participants shouldbe able to familiarizewith:. Meter Types. Meter Connections. Meter Installation. Whole Current (WC)Meter, Current and Voltage Transformer (CT & PT) Meter

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I CIATlONFOil ENGINEERS."INTRODUCTIONElectrical power is measuredbyWattmeter. The electricalpower is the rate atwhichelectrical energy is used and its unit ofmeasurement is the Watt while the unit ofmeasuring electrical energy is Watt-hour.The instrument used to measure the electrical

.~.~kWh ~rQJm[gJ()ITJI:.6':- -- .~.- 00. ,;.::"energy is Watt-hour meter, which measuresthe total electrical energy during specific Fig. 4.2-1 Kilo-Watt-Hour Metertime as kilo-Watt-hourmeter. (Fig. 4.2-1)MEANS OF MEASURING ELECTRIC POWERIn alternating current circuits, power is the product of three quantities the potential(Volts), the current (Amperes) and the Power Factor (%). Power is measured by aWattmeter as:

Active Power (P) = VI Cos cl>(Watts)EXTENSION OF WATT-METER RANGEThe range of Wattmetercan be extended on AC ouree HI H2 To loadcircuits by the use of HI Xl CT50/5 X2instrument transformers 4800/120 -(PT & CT). A PT is

never be open circuit. Boththe PT and CT multiplying

wonnected to the movingcoil circuit. CT should

-

""Amperes

450watts112.5VoltsFig. 4.2-2 InstrumentTransformers (PT & CT)factors must be applied to

the Wattmeter reading,(Fig. 4.2-2).

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Fig.4.2-3shows examplesof kilo-Watt meters andFig. shows KW.2-4meter connections.

Fig. 4.2-3 Kilo-Watt Meters

.........;$ :2 1 fvori -..32....... ....PT

"t-IDa:ITbt",,""'re. thtft-phase ;nttlfltih!r \wiUI(;!)rrenfltlm$fqrmeu,and potetlt..!tr4l1$f

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-- ---- - -- - - - -- -

BIt is common to have a condition where VARs are equal to the Watts. This is onereason why overload occurs to feeders. Many substations have installed capacitors tocompensate for this condition.WATT-HOUR METERSThe WHmeter is an instrument that is used to measure electrical energy. The (KWH)meter is an instrument that is used to measure electric energy sold by SEC. Its functionis to provide an accurate record of the electric energy. KWH meters measure theamount of electric energypassing through various parts of the generating, transmissionand distribution systems.Some KWH meters areequipped with demandregisters and named Watt-hour demand meters. Thedemand meters indicate orrecord the peak demand orthe maximum demand atgIven time period. Fig.4.2-6 shows example of

Fig. 4.2-6 MaximumDemand KWHMeters

maxImum demand KWHmeters.In principle, the Watt-hour meter is a small induction motor whose instantaneousspeed is proportional to the power passing through it. The total revolutions in a giventime are proportional to the total energy or Watt-hour consumed during that time, Le.,a Watt-hour meter will indicate 1000 Watt-hours if connected for two hours in acircuit using 500 watt.

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APPRECIATlOII fOR ENGINEERS

CONNECTED LOADIDEMAND LOADCONNECTED LOAD: It is the combined rating of all the appliances or equipment

of the customer connected to the system.DEMAND LOAD: It is the load demanded by the customer averaged over a suitable

and specified interval of time.CLASSIFICATION OF METERS ACCORDING TO TYPEMETER TYPES. WHOLE

METERS(WC)URRENT

Used for voltageowcustomer load not exceeding150Amps.

. CURRENT TRANSFORMER(CT) METERSUsed for customer loadexceeding 150Amps.

. CURRENT AND VOLTAGETRANSFORMERS (CT&PT)METERSUsed for customer load frommedium voltage 13.8 kVand above.

4J~'

~,~I~l#' ~b~J $UPPLY1 SQPR!=E(MINJPltAR jII

,-~loMt'Jj~ ,METERBP)(~IIIJII

+ ~l L-~~'. Jot.\)

SERVICj: CA!3Ct ...'.f.~..~'~I~. .. .TERM,:t."nkOC It ...o\S"# 4t\.eJ-\J.Ld)\ i~f.cc. CX.OLATK0PRO.TECII.c .)

4S"~, ~I.,)~I )\...lPWC KWHMETER

CUSTOMER LoAb.wc'HE:rERJ:NG OUTDOQRAJiU~A"'G9IENT

Fig. 4.2-7 WCMetering OutdoorArrangement

STANDARD METER CONNECTIONSFig. 4.2-7 showsWCMetering OutdoorArrangement.

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Fig. 4.2-8 shows WCMeteringConnection Outdoor

Fig. shows LV.2-9Metering Outdoor !IndoorArrangement upAmps.

200o

APPRECIATIONfOB EHGIIfURS- - - -. Standard. Jlll'eterBoxSECSTANDARD3-4> 4WIREKWH JIIIETER .....MCCB ...

eu.n:oaae.. rDted-Te 1aaJsIDe_iag.J Cor euatOdler

Supply CU8a'OSD- GroIuut Wire BoodeetTe UiIoJs Wit:b l!I'eutnll

Fig. 4.2-8 WCMetering Connection Outdoor

SCR,VIC '''SLjlplt J.I d~CT80Jl!

290.""., ,1t.;C ,PU""rp"OTCTIO. ~Z~OLATZ.OD.vZCa.j,.t'2004J~ ~M.. ~,~t1TbUNGT--

-+-.tUSTOMER:fU"""" I'CIt cvST~ cA8I.tTtR""A'nOM ,Ar J.rc; C lJ$\ 'Dt1R,1!nII-'FACf 1'00Ht.

-=.I :J~'~.s',,:.I1~ f,1iI11U~J~I~~JJ~IJi".CUSTOI1ER CABLE WIn,$OUJoIO WtR; AStUIICUSTO"EIf BREAlClJtf'ORCOIfTRQI.!.iHG HI$ ""HOurIN~TALL" T101'l

CUSTOMER tOAD jS""u' J\J>fLV CT ...E1'ERIHG CtJTDIX)R / INDOOR ARAAtlGEHENTuPTO 200 AMPS (TY'PYCAL)

Fig. 4.2-9 LVMetering Outdoor !Indoor

249

.. -...

....

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APPRECIATIONFORENGINEERS

Pig.4.2-10(a-b)hows meter box installation.

Fig.4.2-10(a)Fig. 4.2-11(a-b) shows circuit breaker insidemeter box.

Fig.4.2-10(b)

Fig.4.2-11(a) Fig. 4.2-1 1(b)CT & PT CURRENT AND VOLTAGE TRANSFORMERSTable 4.2-1 shows the Dimensionof CTs, bus bar and cable size.

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Table 4.2-1 CTs, bus bar and cable size

Fig. 4.2-12 shows LV CTmetering connection.

SEC STAND~12 CORE 2.5~J .HI4CONTROL CA

J,.-.: .1"""j,...w.:.C CT METER BOX

sJ!J4-:->, .JLo~j~TV TEST DEVICE (STD)

~ ~~~ J~Lo.NDUIT FOR CTNECTING CABLE

FUSE/(SOLlD~- ..:. '''': -:...LINKS ~ -----....

..POWER FLOWLV CT METERING CONNECTION

- -, J~I J,.-o .;, ...w.:.,..- CTBOXIIIIII~, .is,,..,wJSEC

1~ ~~ICUSTOMERFig. 4.2-12LV CTmetering Connection

251

--.-

Cable Maximum DimensionCurrent Transformer Busbar Height 'Width Depth200/5 Amps 1'&30mm 110mm SOmm 55 mm300/5 .I\mps 1'&30mm 110mm SOmm 55 mm4001'5Amps 1'&30mm 1l0mm gOmm S5mm500/5 Amps lxlOxl00 mm 110mm SOmm S5mm600/5 Amps lxlOxlOO mm800/5 Amps lxlOxlOO mm1500/5 Amps lxlOxlOO mm3000/5 Amps 2x1Oxl00 mm400015 Amps 3x1Oxl00 mm

. II II ..-.II II SCECOEAST II STANDARDTHREE PHASE II FOUR WIRE CTMETER II II 1 2 3 4 5 6 7 8 9 10 II II L ..l I II L..- I'- II II I.1 -I I ....J II2/

II 5/8110

6 .....-+-- .1I 1 6 )< 7 I SE1 ...1- II - -,- J""'\ --- - - - - - -D I I JIm2 I '-+- (I CCII I

>-01 I-..1 - - 1- - - f-- -- - -'----.1 .. 82'-., '1:P1 .x.>

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APPRECIATIONFO.RENGINEERS

MEDIUM VOLTAGE KWH METER WITH CURRENT ANDVOLTAGE TRANSFORMERSFig. 4.2-13 showsMVmetering installation3-wire systems 3-phase, 3-wire, 2 element,CT, PT operated KWHM.

SEC12~1":f::~1CONTROL CABLE

r ,1 I! 4J I jl~ ,I STANDARD3~;3~RE II 2-ELECTRlCAL1AND .I P1OPERATEDWH II METER ,I 'JO II I S~I I STANDARD1 '. SAFETYTEST \.-I Q'J """-" ul.~ UA

jDEVICES ~ ~ ';-.J: . FROM VT CIRCUIT

; ~ '->'"l:!iJI;;~J~":; ul~ ~4~ ~y1: " b jWl ~I ~ljTERMJNALBLOCKSI I FORHVMETER-_J CONNECTION

.)1+i11~'J~ jJIJ~ UAFROM CT CIRCUIT

:>';:5

II 1"- I~ r".. - - 1...L"..l.. - ~~~'.!.l~alb jWl ~I ~lj '->'"4iJ1;~~ '->'"l:!iJI;;~, I METERING UNIT "I I INSTRUMENTS II

Ammeter II Voltmeter I

I I Ammeter Selector Switch. VoltMeterSelectorSwitch II . I II I ~~I~ I.~. -"" l...W.\ Ui.. III ~.). .c I.~..~'.m ~I Ui..I!..I---I I ~~ .) . ,C ,!J I I I

'~I ~ 1-'-\~ 1..1;.,L.~-:t''4-"Ti -Lii.ln~.I.uttJi"~I~-_!.).,... f'.J c.;- . '->'". ~.)1+UJu'i~J ~ m~J I

HV METERINGINSTALLATION3WIRE SYSTEMS3-PHASE,.WIRE,ELEMENT,T,VTOPERATEDKWHM

-. -. - _-_aCUSTOMER~ ~~I,/ I '", I ",

b jWl ~I ~Ij '->'"4iJ1;~JHV METERING UNIT

071':

'"t ':1

at"'")01 ." I ,"SECV

Fig. 4.2-13MVmetering Installation

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Fig. 4.2-14 shows CT/PT metering arrangement incorporated in bulk supplyMVCircuit Breaker.

MV Loadbreak.Oil Switch

CUSTOMER

Switch CODDectioDs

MV Bulk Supply SubStatiODRoom Supply By Cousmmer

SEC

Customer MY CB

CustDmer~butioD

Fig. 4.2-14 CT/PTmetering inBulk SupplyMV Circuit BreakerINSTALLATION OF KWH METERS INSIDEMETER ROOMS AND INSETSThe standard specifies the design of meter room and method of installation of KWHmeters inside the meter rooms and building insets. It is intended to assist the fieldengineers and technicians to achieve uniform standard in construction to ensure asatisfactory and economical level of service without operating restrictions so that theoperational errors are minimized for safety and reliability of the system.METHOD OF METER INSTALLATION1. Mainly the quadruplemeter box (Four meter boxes) shall be used for any groupinstallation.

2. Single, double, CT and remote meter boxes shall be used in conjunction withfourmeter boxes to completethe installationas per plan.

3. A space of 10 mm shall be provided between two adjacent meter boxesinstalled side by side as shown in the attachedfigures.

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,"APPRECIATlOIIFORENGINEERS

METERS IN INSETS. As per standard one to four meters can be installed on the front wall of the

consumer.

. For the installation of 4 to 16 meters, the consumer shall provide a wall in aninset to install the meters.

. Meters in the inset shall be installed in meter boxes as per prototype dependingon the number ofmeters in the plan, (Fig. 4.2-15, 16, 17, 18, 19).

. A space of 10mmshall be provided between two adjacentmeter boxes.. A clearance of 200 mm shall be maintained between the meter boxes and theborder of the assignedarea on the right, left and the top of the installation.

. Clearancebetween the bottom of anymeter box and the ground level shall be800mm.

ilml1Iml\;;eJ:.. . "H'..-';ii-, ~ Wiii '

I'ipoohClllllnm /m3 CWIIJ, tIJbI H1w.id1!d:~bDII'''Ibit1m.~ 2-!mm..~ ao1l'1:... P11C~p ~ 2 .]mm 1111"Iec,IJ't: CmInslalLtlon of 5 D1recl rm, cm. '*C8I~c:XWHIl..btn :iD "lb. m_tll ~OMrDiAllio!i1JmIi'I. fillI'Jllhnm.

JNS"J'jUJ.'7JONOJI":uE:r.Im IIDXI'.S

0O-IJI] "ITDD []D [J0 0-..~ ,_I::I,~ ,1:::1

CluwdLwd..'JRmmI Cdfl.!:

Fig. 4.2-15 Meter Box Installation in Inset

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APPBECIATlOIUOB

oil 4 -. - .iiii~-ii .. - -Allr.-"" .IJ : j-" '-.. ~ -.'" , ""'" ""I'lp.- IbrC1lmlmlm

JtIIG0IW9, t:Ob!lpan.id!llI.bY'C~r1hidmllS5 2-:mu.,.~ c-.LID'"WC"Pipe2-JIIIm.I1I;rStt:IiCc.bJe -GQ!lCcrJITI[ IDstaJIJtiOD

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APPRECIATIONORENGINEERS

I

-GIn-'W.J

,..-~~IMt--' \ '---tIitlCW~~.ie~tiy".(.aD. ISo of .t2 ~ .C_~cbeso:J . .. . .2~~. ~CoJu, " PUefINllrlecfleCM18..&.oO-KWB N'I!~. jR t:be ill8e't8 ",,"J1icr-a~OhI:F OIJIIc....INA'i 'AIIu fttm' or ImTml 'IIM8R '.0CMttDiaIiS:Joma"3!lO:Ii8l

Fig. 4.2-18Meter Box Installation in Inset

~N I))t ...., of

Fig. 4.2-19 Meter Box Installation in Inset256

nj

till...~ c:u51 !... ,''''g !Qj1:1 :5- !iii:!; '...= i:~ ii"5i ;::;I: IIIi:I::I

.g[)i1 [.}. P 1.1r.. 1111 ""r4 ji!Jaj J

. ""..I d!b IN6a .eil:...(I01:1 2 11:I "c5 I j

0(.. '..

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METER INSPECTIONAND MAINTENANCEThe Distribution Maintenance Manual (DMM-OI-02) provides precise and adequateinformation on the planned Inspection and Maintenance of MV/LV MeterInstallations. Meter Installations are required to be maintained regularly in order tokeep the meter installations up to SEC Standards to eliminate any potential hazardspresent and to protect SEC from the losses incurred by meter errors developed after acertain period of service.

SAFETY PRECAUTIONS. Ensure that approved personal protective equipment is used.. Ensure that required work clearances (work permit and hold tags) have beenobtained.MAINTENANCE OF METER INSTALLATIONSWhen a problem is discovered at an LV metering installation, in order to restoresupply quickly and minimize customer inconvenience, the shift electricians usuallyrestore power supply bypassing the faulted equipment temporarily. For MY meteringinstallations, problems are handled by Network Operators and Meter Maintenancemight be called out, if necessary. ObservationslRemarks and temporary repairrequiring follow-up action shall be forwarded to the Unit/Segment responsible forMeter Maintenance.

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APPBECIATlOUIIBENGINEERS

REVIEW EXERCISEI-Complete the followingClassifythe meters according to type ofcurrent to bemeasured:

a) (WC) METERSUsed for low voltage customer load not exceeding 150Amps.b) (CT) METERSUsed for customer load exceeding 150Amps.c) (CT&PT) METERSd) Used for customer load frommedium voltage 13.8kV and above.

2-Match the left and right column shown below.

259

1. Use of instrument A. The rate atwhich electrical energy is usedtransformers2. The electrical power B. Extend the range ofWattmeter onAC circuits3. The three-phase C. Is never open-circuited.Wattmeter4. VAR meters D. Tomeasure three-phase power5. Two single phase E. Measure the product of voltage and currentWattmeters component, which is 90 out of phase with thevoltage.6. Current transformer F. Is a combination of singlephase Wattmeter elementsthat drive a shaft at a speed proportional to the totalpower in the circuit

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--- ----.-----

APPRECIATIONFOBENGINEERS""",,'''''''111'

UNIT-5ELECTRICAL DIAGRAMS, SWITCHINGACTIVITIES,

LINEMAN AND CABLEMANUNIT OVERVIEWDESCRIPTIONThis unit consists of four lessons:Lesson 5.1 familiarizes the participants with different types of Electrical Drawingsused for maintenance and troubleshooting of electrical power systems. This lessondescribes the layout and single line electrical diagrams.Lesson 5.2 familiarizes the participants with Switching Activities of electricalsystems. The switching activities include switching to transfer load, switching toenergize isolated circuits, switching apparatus with remote operation facilities as wellas hold tags and lockout, grounding and safetyprocedures.Lesson 5.3 for Lineman and Cableman Activities, discusses how the lineman in SECmaintains and constructs OH Distribution and Transmission lines and beknowledgeable of materials, work procedures and safety precautions necessary toperform his job. The cableman's duties include the quality of joint and terminationwhile using manufacturer instructions for installation, making precise measurementsand cleaningjoints byproperly applyingheat to shrinkablematerials.In Lesson 5.4 for Cable Splicing Activities, mainly Cable Receiving, Safety Aspects,Work Procedures, Work Site Preparation, Direct Burial of Cable in the Ground andTrenches, Cable Preparation, Joint and Termination, Pre-Commissioning Tests,Ground Testing byMegger, ContinuityTests and Phase Rotation Tests are discussed.

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APPREClATlOIFORNGINEERS

OBJECTIVESUpon completionof this unit the participants should be able to familiarize with:. Layout and single line electrical diagrams.

Block diagrams.. Schematicdiagrams.Switchingto transfer load.. Switching to energize isolated circuits.Switching apparatus with remote operation facilities.. Hold tag and lockoutprocedures.Grounding and safetyprocedures.

. TransmissionandDistributionLineman Duties.Hazards, Materials, Equipment and Tools Identification, Work Procedures andSafetyPrecautions. Transmission andDistributionCablemanDuties.

Cable Receiving, SafetyAspects and Work Procedures, Work Site Preparation,Direct Burial of Cable in the Ground and Trenches Cable Preparation, Joint andTermination

. Cable SplicingPre-CommissioningTestsGround Testing byMegger, ContinuityTests, Phase Rotation Tests

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L ISON5.1, '

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APPRECIATIONOilENGINEERS;!i"

LESSON 5.1ELECTRICAL DIAGRAMS

LESSON OVERVIEW

DESCRIPTION

This lesson describes the layout and single line electrical diagrams, including Blockdiagrams and Schematic diagrams.

OBJECTIVES

Upon completion of this lesson, the participants shouldbe familiarizedwith:. Layout and single line electrical diagrams.. Block diagrams. Schematic diagrams

Task 5.1-1: Isolating Power Transformer (T-703) 230 /69 kV

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APPRECIATIONFORENGINEERS

INTRODUCTIONBefore we read and correctly interpret the electrical diagrams, we will define thedifferent types of the electrical diagrams as follows:. Block diagrams represent all electrical network equipment as blocks to showpower flow.. Single line or one line diagrams are shown by single lines and graphic symbols.. Schematic diagrams are the basic reference for control circuits and electricians

use them to understand the operation of control circuits. Schematic diagrams aremade of standard symbols, function numbers and lines.

BLOCK DIAGRAMSBlock Diagrams represent all electrical equipment as rectangular functional blockswith text interconnected by arrowed lines, the arrows indicating the signal flow.They do not use standard symbols or abbreviations. The purpose of the blockdiagrams is to:

. Show the flow of power through a system/equipment in one or more stagesof functional blocks.

. Understand the system operation.-1- STATICSWITCHES

CRITICALLOAD

-1-Fig. 5.1-1 Block Diagram of Uninterruptible Power Supply(UPS)

As the system equipment gets complicated, its drawing gets simpler. This is becauseit will be drawn as stage-by-stage block diagram. In troubleshooting, the electricianwill just measure and compare the output of each stage. Any faults may exist whereit deviates from normal.

269

For example, Fig.5.1-1 shows theblock diagram for NORMALUninterruptible I SOURCEPower Supply (UPS).

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SINGLE LINE DIAGRAMS. Single line diagrams

are simplifiedrepresentationscomplex circuits orentire systems. Thesingle line or oneline diagram (Fig.5.1-2) is the mostbasic diagram usedin electrical powerindustry, because itis actually a "shorthand" methodrepresentingcomplex

mostpower

system. The singleline diagram may beused III a very

of

3x300mm2 13.8KV CABLE

-(- &-f:;~~+-~ f

. ~~:~-f~ II I400 A RING SN, ITCH III-!:y . . ---11':I II II .. 1I .. . II 100 A FUSEDf J1 IS~TCH .--,l+--c zcc:iEGz0.::

of

Fig. 5.1-2 Single Line Diagram for Unit Distribution Substation

general andabbreviated manner to illustrate broad system ideas or in a very detailed manner toillustrate all of the components in a particular part of the system.

. Single line diagrams show circuits as single lines irrespective of the actual numberof conductors or phases in it. It uses standard symbols and abbreviations. Theirpurpose is to give a pictorial overview of an electrical system.

. Single line diagrams are used primarily in the electrical power and control areas.

. The single line diagram does not represent actual wiring, but only indicates thatsome kind of connection exists between components.

. Typically, single line diagrams are used to show how power is distributed to variousloads in a facility. This information is useful when determining how to isolate apart of the system for maintenance.

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APPRECIATIONOBENOII/EERS

As shown in Fig. 5.1-2, single line diagrams can also be used to show how meters(Ammeters/Voltmeters) or protective devices (fuses) are connected to the system.Along with identifying the components of the system, single line diagrams usuallyinclude additional information, such as:

1. The major components, switching devices and connecting circuits in a system.2. Ratings of the major components (Ring Switches, 400 A).3. Voltage level at various points in the circuit (13.8-231/133 kV).4. Control functions provided in the circuit.5. The path or power flow in a plant or a system.6. The specifications and types of each equipment used (voltage level, CB

rating, transformer capacity, vector group etc)This information is useful to:1) Understand system, generally. 2) Decide how to isolate a part of a systemfor maintenance.. In some single line diagrams with

three slashes are drawn on a singleline, the three slashes on singleline representing three conductorsper phase,as shownin Fig. 5.1-3.

. The single line diagram is read bystarting from a point nearest to thepower supply and following theline through the entire diagram.This method is useful in locatingthe correct circuit breaker toisolate a componentmaintenance.

THREE LINE DIAGRAMS

4001231V 3IN-50Hzfor

220 VIKVA60Hz42V

Fig. 5.1-3 Three Conductors/Phase, singleline diagrams

It is an expansion of the single line diagram. Its primary purpose is to illustrategraphically the electrical connections and functions of the metering and power

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APPBEClATlOUORNGINmS

control circuitry. It doesn't show the control of power equipment. These diagramsare usually done for substations. Fig. 5.1-4(a) shows three line diagrams for a LVdistribution cabinet. It shows the details of:. Voltmeter and Ammeter connections.

. Protective devices (fuses).

. Instrument Transformers (CTs).Fig. 5.1-4(b) also shows an example of three line diagrams.

SFi SF2 SF5 SF$F3 SF4(60 A FUSES)

(a}

400 VIiiN -1-LtL2L3

(hI

Fig. 5.1-4 Three Line DiagramsSCHEMATIC DIAGRAMSSchematic diagram in Fig. 5.1-5, also called "Elementary Diagrams", like the otherelectrical diagrams, are made of symbols and lines.

.~ r f ..} JL1 rL I\,--~-U ~L2L2--c::::D---e-~1 ~

L3L3 """""" 1\,--';::-11--.1':(.,Fig. 5.1-5 Schematic Diagram of Power Circuit for 3