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What is transformer :an electrical device that converts AC electric energy at one voltage or current level to another voltage or current level at the same frequency

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GStep up Step up Transforme Transforme rr 20 / /150 kV 20 150 kV

150 kV

20 kV

0.4 kV

Interconnecti Interconnecti on on Transformer Transformer 150 / /20 kV 150 20 kV

Distribution Distribution Transforme Transforme rr Load 20 / /0.4 kV 20 0.4 kV

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Basic Principle of Transformer:- consist of two inductive coils (primary and secondary) which are electrically separated but magnetically linked - mutual induction between the two circuit - if one coil is connected to a source of alternating voltage, alternating flux is set up in the laminated core which is linked with the other coil. Then it produces mutually induced emf. - If the second coil circuit is closed, a current flows in it and so electric energy is transferred. V 1 N 1 N 2 V 2

E = 4,44. f . m .NI1 N = I2 N2 1

E1 V = 1 E2 V26

U Is

I Upp

Us

Np

Ns

SIEC = Up x (Is x Ns/Np) SANSI = Us x Is Cooling capacity = IEC 60076 = max. load loss + no load loss 100% excitation +sun rad. sun rad.

ANSI C57 = max. load loss + no load loss (100% + V) excit.+7

There are two type transformer based on its insulation : The party active is immersed in the tank by dielectric liquid The party active is immersed in the tank by air or gas

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The expansion of dielectric takes place in an expansion tank placed above the tank

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Expansion of the dielectric is absorbed by compensating on the radiator fins

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The oil volume expansion is compensated with inert gas layerbetween the surface of the dielectric and the top of the tank.

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HV 60 oblique winding patented by AREVAthree dimensional computerized control automatic and vertical winding machine

micro ordinat eur

fully automated casting and mixing under vacuum12

No liquid dielectric no danger for environment due to oil leakage no loss of dielectric strength due to oil leakage no need for oil dams or containment systems no fluids to be targeted for regulation in the future resulting in costly change-outs Excellent Fire resistance self-extinguishing, fire retardant, not explosive, no release of toxic or corrosive products and opaque smokes in the event of fire Excellent response to service conditions High short circuit withstand ratings Resistant to mechanical and thermal stress caused by over-loads, over-voltages and harmonics Low partial discharge, therefore high life expectancy

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- Core - Winding - Cooling medium - Insulation structure

- Cooling equipment - Termination - Control/Protection

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Tank cover. Internal connection bushings Tap changer barrel and lead outs connection Core & coil assembly Yoke clamping Pedestal Tank wall + base.15

Transformer for Hazardous Area Transformer for Hazardous Area

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Basic description : Definition : Those areas where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust or ignitable fibers For hazardous areas with risks of explosion, specific electrical equipment is required. Application fields: Based on decades of filled tested experience in electrical generation and distribution for both offshore and onshore installations

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Arcs and sparks produced by the normal operation of equipment, like motor starters, contactors and switches, can ignite a hazardous location atmosphere The high temperatures of some heat-producing equipment, such as lamps and lighting fixtures, can ignite flammable atmospheres if they exceed the ignition temperature of the hazardous material. The National Electrical Code requires special marking of heat-producing equipment with temperatures above 100C (212F) Electrical equipment failure is another way an explosion could be set off. A burn out of a lamp socket or shorting of a terminal could spark a real disaster in a hazardous location

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Zone 0

: an area in which an explosive gas atmosphere is continuously present or present for long periods

Zone 1Zone 2

: an area in which an explosive gas atmosphere is likely to occur in normal operation: an area in which an explosive gas atmosphere does not normally exist

Type of Area Continuous Hazard Intermittent Hazard Hazard under abnormal conditions

IEC ZONE 0 ZONE 1 ZONE 2

NEC DIVISION 1 DIVISION 1 DIVISION 2

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EXPLOSION PROOF TERMINAL BOX

SEALING FITTING

20CONDUIT CABLES

Standard Applicable

IEC 76, ANSI C-57 and AS 2734Information required with enquiry and order: A.General Information - dry type or oil immerse - single or 3 phase - frequency - indoor or outdoor - type of cooling - rated power and voltage - tapping (if needed); on load or off load - highest voltage level - method of earthing - BIL and power frequency - connection - Accessories B. Special information - impedance - altitude and ambient temp. - special installation space - tests required : lightning impulse etc. C. Paralel operation

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Part active : this is the main part of transformer, consist of coremagnetic and winding

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Bushing Cooling Device : oil (for oil immersed transformer), radiator, fan Protection Device : Bucholz relay, protection relay for OLTC RS 2001,pressure relief device, pressure vacuum gage & bleeder

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Accessories : Oil Level Indicator (OLI), Oil Temperature Indicator (OTI),Winding Temperature Indicator (WTI), etc

Valve : oil sampling valve, butterfly valve, screw end globe type valve

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- Magnetic core - Low voltage winding - High voltage winding - Active part clamping

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1 3 4 2 1 Top yoke 2 Bottom yoke 3 Left outer limb 4 Center limb 5 Right outer limb 5

LV Winding Gradins HV Winding

Choice of gradins used must be as close as possible to the circle section24

There are two kinds of magnetic core stacking : 1. Flat yoke : The silicon steels of the yoke are arranged with the same distance to each other

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2. Non flat yoke : The silicon steels of the yoke are arranged like stairs

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There are three kinds of wire used for winding: 1. Round wire (email) 2. Rectangular (meplate) 3. Foil (Bande)

Current density () limitation used :Copper wire : 1.4