Dry Type Transformers-ideal for FPSO

8/11/2019 Dry Type Transformers-ideal for FPSO

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ABB GroupSeptember 24, 2009 | Slide 1

Dry type transformers-ideal for FPSO

- Transformers for electrical and drivesystems

Ar ild Furnes,ATPA OGP/Petrobras workshop, 22.09.09


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Transformers for Ships and Offshore - Standards

IEC 60092-303 Electrical installations in ships, Part303 equipment -

Transformers for power and l ighting IEC 61892-3 Mobile and fixed offshore units, Part 3

equipment -

Clause 5 -Transformers for power and lighting

Both refer to general transformer standards IEC 60076 (alltypes) and IEC

60726 (Dry type transformers) Preferably air cooled dry type

Liquid-immersed transformers preferably hermeticallysealed type, no spilling of liquid


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Transformers for Ships and Offshore - Standards

Differences to be noticed to on shore applications

Environmental conditions

Air temperature higher (45 C or higher) = reduced temperature rise

Cooling water temperatures high = reduced temperature rise

Humidity and salt = degrees of enclosure

Inclinations, static and dynamic = mechanic requirements

Acceleration and vibrations = mechanic requirements, flexibleconnections

EX-classified zones = specifically designed transformers

Materials to be used

Self extinguishing

High tracking index

Halogen free


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Classification often required /ABS, DnV, Rina, Loyds etc)

Type testing and special tests often required. Routine testsmandatory according to IEC.

Insulation between HV and LV systems

Normal practise to have earthed screen between HV and LVwindings

Reduces capacitively transferred overvoltages fro HV side toLV ITsystems

Reduces transferred EMC disturbance from drive systems toship distribution system

Screen is technically clear requirement, increased or

improved insulation of HV systems is not

Drive supply transformers should have the screen for EMCreduction, all high power drives make EMC-noise to supplynetwork

Screen inside transformer is economic way to block EMC

Transformers for Ships and Offshore - StandardsDifferences to be noticed to on shore applications


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Transformers for Ships and Offshore - StandardsDry transformers-Technologies

Dry type transformers IEC 60726

Fire class F0,F1,F2

For ships only possibility F1 (self extinguishing), F2 should be able operate

under fire for limited time is not existing Impulse voltage level according to list 2 (higher alternative)

Vacuum breakers create switching over voltages, more margin

3,6 kV = LI 40 kV

7,2 kV = LI 60 kV

12 kV = LI 75 kV

transformers at end of short cables (100-200 m) critical

If the LI level is not mentioned, you may be getting the lower oneie list 1

Classification rules have no impulse voltage requirements Area to be improved

Dry type transformers cannot be installed without extensive measures onExplosion Hazard Zones at all, but must be installed on Safe Areas

Temperature hot spots on coils, Sparking and charging at switching on


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Transformers for Ships and Offshore - StandardsDry transformers-Technologies

Dry type transformers IEC 60726

Encapsulated type = resin encapsulated (cast resin or filamentwound inside resin)

Non-encapsulated types =open wound (traditional, with limitation)

Environmental class E0, E1,E2

For ships minimum E1 ,can be energised while having moisture onthe transformer coils, but note that in the standard no switching

overvoltage is considered (known to be a problem with vacumbreakers of certain designs in small offshore networks)

E2 recommended (can operate while humidity is being sprayed onthe transformer, has more margin compared to E1)

E1 and E2 can be reached only with encapsulated designs

Climatic class C1,C2

For ships minimum C1 (-5 C) is sufficient

For scandinavian Yards C2 (-25 C) is necessary while buildingships


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Most common variants of dry type transformersOther important considerations

Rectifier duty.

Derating approx. 20 % with

6 puls diode rectifier. Primary phase shift

removes possibility fortapping, no-load voltageneeds to be carefullyselected from system study

Several cooling alternatives

available for both dry type

AN, AN/AF, AF/AF, AF/WF

Ingress protection of enclosure

The higer number, biggerunit not to exceed thermal

limits

Two dry typetransformers incommon enclosurefor 24 pulse rectiferduty.

Petrobras requiresdedicated enclosureas per today.


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Most common variants of dry type transformersOther important considerations

Both size and audible noisecan be reduced by materialselection and design.

High grade orientend core steel

High grade copper wire or foil

High impedance many turns,low impedance fewer turns

Influences the physical

dimensions

Vacum cast coil


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Most common variants of dry type transformersDry VPI open wound with paper

Recommendations for offshore applications

Only for LV distribution

Below 500 kVA AN

Indoor in controlled environment

Salt laden air will degrade

paper insulation over time

Up to approx 12 MVA

15 kV

Several cooling options available

Both Cu and Al windings available

Cost efficient

Petrobrasspecifications ingeneral calls for resinencapsulated types


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Most common variants of dry type transformersVacum Cast Coil

Classes: E2, C2, F1

Partial discharges:


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Most common variants of dry type transformersResibloc

Classes: E2, C2, F1

Partial discharges close to zero

Insulation : 155C (F), 180C (H)

Design Temperature: 40 C

Design according to class up to 55 C

amb. or 38 C for cooling water.

Up to approx 40 MVA

45 kV

Several cooling options available

Both Cu and Al windings available

Glass-fiber reinforced, crack free

Wound resin impregnated coil


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MTBF Resibloc Transformers433 years !


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Why use dry type transformers on FPSO

Easy to install, simple foundation and enclosure

Very clean, no oil, pits etc.

Less fire load (energy) than oil filled

Epoxy has higher ignition temp than special synthetic ester

Can be assembled offshore by skilled service people

Easy to connect cables and/or bus-ducts

Easy access for inspection through bolted covers or hingeddoors

Easy to install fans later to increase power if provisions(Space under coils) are made. Approx. 30 40 % increase

Practically maintenance free


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Why use dry type transformers on FPSOAreas to consider liquid filled transformers

Outdoor location in case of limited HVAC and indoor space

Highly corrosive offshore location. Tropical condition

worse than cold in this matter. Exposed parts of Liquidfilled are galvanized and painted.

Zone requirement

Dry type not suitable due to difficulties to ensure no

hotspots on coils and sparking during energizing. Very high power

Due to weight and size.

Multi winding transformers for drives (more than 3secondaries due to balance of impedance/flux) Liquid filledare more flexible with respect to phase shift.

If OLTC (on load tap changer/AVR) is needed

Very large OLTC for dry types.


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Why use dry type transformers on FPSOLiquid filled application

Roof of FPSO E-house

Compact liquid filled

Corrugated tank design

Conservator type design

Zone 1 or 2 outdoor

FPSO outside WestAfrica.

Multi Phase PumpPower ControlModule with

drives inside


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Why use dry type transformers on FPSOLiquid filled execution

OF/WF transformer forpropuplsion

Seawatercooled

Syntetic ester,biodegradeable

300 deg C flamepoint Most compact design

available,

Very beneficial on large

compressor drives etc.


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Why use dry type transformers on FPSOLiquid filled on module outdoor

Single lift PowerControl Module forsubsea Multi PhasePump

Liquid filled

transformer installedoutdoor on frame toreduce need for largecooling units insidemodule


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Dry type transformer with water cooling AF/WFIncreasing interest in the offshore and ship market

Reduces need for HVAC andducts

Reduces audible noise

Approx. 5 % of losses toambient, rest to water

Min. IP 44 design enclosure

Cooler for seawater available(double titanium tube)

Redundant blower and coolerarrangement available

No liquid carryingpipe allowed.

Clause 1.4 inPetrobras

I-ET-3000.00-5140-700-PCI-001ELECTRICALBASIC DESIGNGUIDELINES


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Dry type transformers in a systemWhat can ABB do ?

Provide the best technologies available conforming withPetrobras specifications and applicable regulations.

Take responsibility for the integrity of the complete Drive systems

Electrical system

Load flow calculations and considerations( impedance,no-load/nominal voltage of the transformer and voltagedrop during DOL motor starts)

Harmonic calculations (THD)

Provide transformers which offers the best possiblecancellation configuration with the VFD

Provide and dimension pre-magnetizing system forreducing inrush current when energizing the transformers

Up to 1/18 reduction of inrush current !


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Dry type transformers in a systemConfiguration of converter duty transformers

Distortion with 6 pulse




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Dry type transformers in a systemSimple pre-magnetizing system

T1

C2

C1

C3

T2440 V

Simple and cost effective ifback up supply available

Integrated in transformerenclosure

In Switchgear

Separate assembly

Figure of pre-magnetizingsystem in a essential modedrilling transformer to 690 V

drilling drive system fromweak 440V emergencysupply network

D t t f i t


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Dry type transformers in a systemPeregrino WHPs

Total 10 units for waterinjection, booster andproduction pumps

ACS 1000i

24 pulse integrated dry typetransformer


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Dry Type Transformers-ideal for FPSO

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