HiDry72

Dry power transformers for sub-transmission level

© ABB Group - ConfidentialSeptember 1, 2015 | Slide 1

José Cano, August 2015

HiDry72

Why?

Why HiDry72?1. Safety

Incidents in GIT,gas insulatedTransformers dueto gas leakages ofSF6

CIGRE 2013 “Guide for transformer firesafety practices”:

* Power transformer fire rate ~0.1% per year

Incidents in oiltransformers dueto internal orexternal causes

Why HiDry72?2. Ecology

Why HiDry72?3. Reliability

§ Based on:

§ Very high MTBF/ Zero failure rate up to date

§ Withstand shortcircuit test passed succesfully inCESI (31,5 MVA, 66 / 20 kV with OLTC) in 2014

HiDry72

What?

Rated power up to 63 MVAPrimary voltage up to 72.5 kV

Lightning impulsevoltage

325 kV for IEC 60076-11350 kV for IEEE C57.12.01(negative wave)

Short duration AC 140 kVSecondary voltage up to 36 kVConnection group Y or DOn load tap changer/taps

HV side17 positions (+ 8 x 1.25%)

Cooling AN, ANAF, AFAF, AFWF

Enclosure (IP, or itsNEMA equivalent)

IP00, IP21 (indoor) to IP54or IPX4D (outdoor)

Partial discharge < 10pCInsulation class F (155°C) or H (180°C)Environmental class E2Climatic class C2Fire class F1

What HiDry72

The scope

What HiDry72

DETC, Tappings (off-load)

§ The standard number of positions is 5(+/-2x2.5%). More positions can bemanufactured on request

§ Connections are normally bolted

What HiDry72

OLTC (on-load tap changer)

Characteristics of OLTC:§ Dry, oil-free technology

§ Air contacts§ Vacuum breaker

§ Suitable for linear type winding configuration§ Installation on HV side.§ Current design

§ For up to 17 positions and ±10% regulation(*)

§ Max voltage step 900 V§ Max current 500 A

§ Low maintenance§ Increases transformer width due to higher

clearances in air(*) presently limitedavailability, pleasecontact us forclarification

What HiDry72

Accesories

HiDry72

Where?

Where HiDry72

Applications areas

§ Urban (inner-city) substations

§ Indoor and underground substations (Basements)§ Airports, Commercial, Buildings, Metro, etc.

§ Fire risk, even for outdoors installations§ Indoor substation, National Parks and forests

§ Environmentally sensitive areas§ Water reservoir§ Water protection areas (rivers, lakes)§ Islands§ Forest

§ Heavy industry substations§ Chemical, pulp&paper, oil&gas, metals&mines, etc

§ Renewable generation§ Hydro, off-shore wind turbines, solar, etc

§ Retrofits

HiDry72

Customer value proposition

HiDry72

Customer value proposition (benefits)

1. Safety: fire risk limited

2. Ecological, no polution

3. Reliability and excelent responseagainst shortcircuit

4. Substation CAPEX is reduced in caseof indoors, due to savings:

1. Civil Works

2. Assembly on site

3. Anti fire systems

5. Reduced operation and maintenance

6. Insurance savings

7. Easy repair on site

What HiDry72

Advantages and benefits

Safety§ No flammable liquids:

§ no explosion,

§ no self-igniting materials,

§ no spread of fire by burning liquid

§ F1 fire behavior class: restricted flammability and minimized emission of toxic substancesor opaque smokes

§ 10-20 times smaller combustible mass than oil transformer: mainly epoxy resin of coils:

§ Does not ignite, but degas due to external heat source

§ Thermosetting polymer, not melting, coil keeps shape

§ Filled with silica, absorbing heat

§ Fire extinguishes when external heat source removed

§ Self-extinguishing solid insulation

§ No SF6 gas leakages

What HiDry72

Upgraded technical performance

§ Great resistance to short circuit effects (thermal and dynamic)

§ Great performance towards seismic phenomenon and vibrations

§ Great capacity to support overloads (IEC 60076-12, ANSI C57.96-1999)

§ More ability to withstand overcurrents arising from applications

§ The highest dielectric strength for dry transformers. Tested BIL up to 380 kV.

§ The best suited for damp and contaminated industrial areas (E2).

§ Suitable for operation, transport and storage at ambient temperature down to -25 ºC (C2), even tested up to -50 ºC.

What HiDry72

Advantages and benefits

Environmentally friendly and cost efficient§ Optimized load loss§ Lower infrastructural cost. Simple installation,

no special civil works§ Minimal requirements for safety and protection

installations§ Very low maintenance§ Easier unload and more efficient logistic costs§ Easy repair at site

HiDry72

FAQs

FAQ, HiDry72

Oil vs dry footprint and weight

§ When rated power is increasing, then comparison oil-dry is reduced.

§ Dry-type needs a slightly bigger perimeter around, due to air-to-air clearances.

Dry type,DETC

Oil filled Dry type,DETC

Oil filled

Length (mm) 4,370.0 4,500.0 4,970.0 5,000.0Length (in) 172.0 177.2 195.3 196.5Width (mm) 2,000.0 2,300.0 2,000.0 2,500.0Width (in) 78.7 90.6 78.6 98.3Height (mm) 4,120.0 4,100.0 4,120.0 4,100.0Height (in) 162.2 161.4 161.9 161.1Weight (kg) 57,200.0 42,000.0 79,800.0 61,000.0Weight (lb) 126,104.0 92,500.0 175,928.0 134,500.0

25 MVA, 66/10 kV 40 MVA, 66/10 kV

FAQ, HiDry72

Layout/perimeter

• For safety reasons, theremust be a fence around theset transformer - OLTC, at500 mm.

• In case of limited space, it isnot necesary any inspectionunder load. Anyway the directaccess to the transformermust be forbidden whenenegized

• Easy access to control box(Temperature, motor driveOLTC, …)

• Since the OLTC frame isgrounded, it can “touch” thewalls arround, keeping theminimum clearances

FAQ, HiDry72

Cooling

• The transformer must be located atleast 200-300mm from the cell walls foreffective cooling

• HV&LV connections must be at least630mm from the cell roof and walls

• The in (A) and out (B) surfaces have atleast the surface áreas in m2 given bythe following formula:

A = 0,185 * P / sqrt (h)B = 1,15 * A

Where:

• P: Sum of non-load and full load-losses of the transformer in kW

• H: Effective height for cooling in m

B

• In case there is no enoughsurface, then heat extraction ismandatory. Air conditionedwould be an option.

FAQ, HiDry72

MaintenanceTransformer:§ Annually: transformers in normal environments

Vacuum cleaner or by blowing with dry air or nitrogen (maximum pressure 3Kg/cm2)

Check and tighten screws, connections, and coil support blocks

Check the thermal protection device that includes the sensors and themeasuring control unit

In case of OLTC:§ Recommended maintenance:

§ 100.000 operations or 3 years, lubrications of internal parts and checking ofscrews.

§ 200.000 operations, checking of vacuum breaker.§ 300.000 operations, replace vacuum breaker + contacts§ 800.000 operations, replace OLTC

§ Savings in time and money.

FAQ, HiDry72

Noise level

• Normally, dry-type transformers present highernoise level (abt 10-20% but depending ondesigns)

• Why:• Bigger core.• Neither oil nor tank muffling noise level.

• Sollutions:• Reduced noise level design (low induction)• Installation of absorbing sound material in

the installation / room

Example:. 30 MVA 66/22 above indicated (standardinduction):

Oil filled acoustic pressure: 60 dBHiDry72 acoustic pressure: ≤ 75 dB

FAQ, HiDry72

OverloadsIEC 60076-12 INTERNATIONAL STANDARDPower transformers –Part 12: Loading guide for dry-type power transformers

Overload capability in a 12 MVA, 66/22kV, OLTC

§ Each transformer has individualized overload capability curves, that willdepend on its design (mass of conductors and mass of dielectricmaterials)

§ When customer requires specific overloads they will be consideredduring sizing of the transformer by engineering

FAQ, HiDry72

Life expectancy• IEC 60076-12 and IEEE C57.96

indicate the way to determine thelifespam on dry type transformers,taken into account:

• Isolation material ageing ratio.• Calculation of loss of life.

• The estimated life expectancy isabout 20 years (180000 hours), atleast, working at nominal conditions

• A temperature increase of 6Kdoubles the ageing rate.

• A temperature reduction of 6Kreduces in half the ageing rate.

• For oil transformers (IEC 60076-7) isthe same life expectancy

IEC 60076-12INTERNATIONALSTANDARDPower transformers –Part 12: Loading guide for dry-typepower transformers

IEEE Std C57.96™Guide for Loading Dry-TypeDistribution and PowerTransformers

FAQ, HiDry72

Overvoltage

§ No damages in case of the transformer is overexcited by 5%(voltage) continuously.

§ Overvoltage causes a higher temperature in the core, it isrecommended by IEC/ANSI, to:

§ Consider it just in emergency / temporarily cases.

§ In any case transformer can withstand transient overvoltages from10-40%, that must be verified according to the specification (FEMmust be done)

§ 10% 1 min§ 20% 30-50s§ 40% 5-10s§ >40% ms

§ Same approach is valid for oil & dry type transformers, due to thefact that this effect is just related to the core induction.

FAQ, HiDry72

Recyclability• At the end of the

transformer lifetime, thecast resin is consideredas an urban waste.

• Don’t need specialdestruction operations orcertification.

(*) With seaworthy (maritime) packing, the percentage of wood ascends considerably

FAQ, HiDry72

Repair at site

• Modular assembly.• Easy replacement.• Don’t need to change a full

column.

FAQ, HiDry72

Repair at site

• Dry transformers have a very bigadvantage, since they are able to berepaired at site, with standard means:

• In case that one of the coils failed, itcould be replaced easily, like atfactory.

• Spare coils are tested at factory beforedelivery.

• Just needed field test after repair are:• Megger• Ratio• Resistance

HiDry72

Configuration switchgear –dry power transformer

FAQ, HiDry72

Configuration switchgear – dry power transformer

FAQ, HiDry72

Configuration switchgear – dry power transformer

FAQ, HiDry72

Configuration switchgear – dry power transformer

HiDry72: business caseEndesa-Sevilla: the safesturban substation in Spain

Customer need§ 4 x 31500 kVA, 66 / 22kV OLTC

(+8 x 1.25%) for replacing oiltransformers in the substation

ABB response§ Dry VCC transformers for main

substation (head)§ An innovating and improved

solution

Customer benefits§ Safety for people and fire hazard in

urban area§ Environmental and ecological

HiDry72

Transformer installed in Sevilla (inner-city substation)

HiDry72

Transformer installed in Sevilla (inner-city substation)

HiDry72

Transformer installed in Sevilla (inner-city substation)

HiDry72

Transformer installed in Sevilla (inner-city substation)

HiDry72

Transformer installed in Sevilla (inner-city substation)

HiDry72

Transformer installed in Sevilla (inner-city substation)

HiDry72

Transformer installed in Sevilla (inner-city substation)

HiDry72: business caseFonte Nova Arena –Salvador de Bahía: thesafest urban substation inAmerica

HiDry72: outstanding success storyBrazil, ABB PS, Coelba, Fonte Nova Stadium-Salvador

Customer need§ 2 x 25000 kVA, 69 / 13.8-11.9 kV

OLTC (+4-12 x 1.25%) for mainsubstation

ABB response§ Dry VCC transformers for main

substation (head)§ An innovating and improved

solution

Customer benefits§ Safety for people and fire hazard§ Environmental and ecological§ Savings in the installation and operation

HiDry72

Fontenova Stadium

HiDry72

Fontenova Stadium

HiDry72

Fontenova Stadium

HiDry72

Fontenova Stadium

HiDry72

Fontenova Stadium

HiDry72

Summary

HiDry72

Take away messages

§ HiDry72 is a dry-type power transformer, with the same funcionalitythan the traditional oil-type transformer

§ Tailorized engineering solution for those applications where theconventional oil/gas transformers are not able to reach the requiredlevels of safety and ecology

§ Best choice for indoor/underground substations

§ Up to date, good experience with dry-type power transformers in 72kV, with a very reliable solution

© ABB GroupSeptember 1, 2015 | Slide 51