Dry type transformers-ideal for FPSO - ABB Ltd type transformers-ideal for FPSO - Transformers for...

© ABB Group September 24, 2009 | Slide 1

Dry type transformers-ideal for FPSO- Transformers for electrical and drive

systems

Arild Furnes,ATPA OGP/Petrobras workshop, 22.09.09


Transformers for Ships and Offshore - Standards

IEC 60092-303 “ Electrical installations in ships, Part 303 equipment -Transformers for power and lighting”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 (all types) and IEC

60726 (Dry type transformers)

“Preferably air cooled dry type”

Liquid-immersed transformers “preferably hermetically sealed type, no spilling of liquid”


Transformers for Ships and Offshore - StandardsDifferences 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, flexible connections

EX-classified zones = specifically designed transformers

Materials to be used

Self extinguishing

High tracking index

Halogen free


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

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

Insulation between HV and LV systems

Normal practise to have earthed screen between HV and LV windings

Reduces capacitively transferred overvoltages fro HV side to LV ITsystems

Reduces transferred EMC disturbance from drive systems to ship distribution system

Screen is technically clear requirement, “increased” or “improved” insulation of HV systems is not

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

Screen inside transformer is economic way to block EMC

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


Transformers for Ships and Offshore - StandardsDry transformers-Technologies

Dry type transformers IEC 60726Fire class F0,F1,F2For ships only possibility F1 (self extinguishing), F2 should be able operate under fire for limited time is not existingImpulse voltage level according to list 2 (higher alternative)Vacuum breakers create switching over voltages, more margin

3,6 kV = LI 40 kV7,2 kV = LI 60 kV12 kV = LI 75 kVtransformers at end of short cables (100-200 m) criticalIf the LI level is not mentioned, you may be getting the lower one ie list 1Classification rules have no impulse voltage requirementsArea to be improved

Dry type transformers cannot be installed without extensive measures on Explosion Hazard Zones at all, but must be installed on Safe AreasTemperature hot spots on coils, Sparking and charging at switching on


Transformers for Ships and Offshore - StandardsDry transformers-Technologies

Dry type transformers IEC 60726Encapsulated type = resin encapsulated (cast resin or filament wound inside resin)Non-encapsulated types =open wound (traditional, with limitation)Environmental class E0, E1,E2For ships minimum E1 ,can be energised while having moisture on the 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 on the transformer, has more margin compared to E1)E1 and E2 can be reached only with encapsulated designsClimatic class C1,C2

For ships minimum C1 (-5 C) is sufficientFor scandinavian Yards C2 (-25 C) is necessary while building ships


Most common variants of dry type transformers Other important considerations

Rectifier duty. Derating approx. 20 % with6 puls diode rectifier.

Primary phase shiftremoves possibility for tapping, 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 thermallimits

Two dry type transformers in common enclosurefor 24 pulse rectiferduty.

Petrobras requiresdedicated enclosureas per today.


Most common variants of dry type transformers Other important considerations

Both size and audible noisecan be reduced by material selection and design.

High grade orientend core steel

High grade copper wire or foil

High impedance many turns, low impedance fewer turns

Influences the physicaldimensions

Vacum cast coil


Most common variants of dry type transformers Dry 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 in general calls for resin encapsulated types


Most common variants of dry type transformers Vacum Cast Coil

Classes: E2, C2, F1

Partial discharges: <10 pC

Insulation : 155ºC (F), 180ºC (H)

Design Temperature: 40 ºC

Up to approx 30 MVA

50 kV



Manufactured by all major suppliers


Most common variants of dry type transformers Resibloc

Classes: E2, C2, F1

Partial discharges close to zero

Insulation : 155ºC (F), 180ºC (H)

Design Temperature: 40 ºC

Design according to class up to 55 ºC amb. or 38 ºC for cooling water.

Up to approx 40 MVA

45 kV



Glass-fiber reinforced, crack free

Wound resin impregnated coil


MTBF Resibloc Transformers433 years !


Resibloc TransformersTechnology highlights


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 hinged doors

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

Practically maintenance free


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 Liquid filled 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 3 secondaries due to balance of impedance/flux) Liquid filled are more flexible with respect to phase shift.

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

Very large OLTC for dry types.


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 West Africa.

Multi Phase Pump Power Control Module with drives inside


Why use dry type transformers on FPSOLiquid filled execution

OF/WF transformer for propuplsion

Seawatercooled

Syntetic ester, biodegradeable

300 deg C flamepoint

Most compact design available,

Very beneficial on large compressor drives etc.


Why use dry type transformers on FPSOLiquid filled on module outdoor

Single lift Power Control Module for subsea Multi Phase Pump

Liquid filled transformer installed outdoor on frame to reduce need for large cooling units inside module


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

Reduces need for HVAC and ducts

Reduces audible noise

Approx. 5 % of losses to ambient, rest to water

Min. IP 44 design enclosure

Cooler for seawater available (double titanium tube)

Redundant blower and cooler arrangement available

No liquid carryingpipe allowed.

Clause 1.4 in PetrobrasI-ET-3000.00-5140-700-PCI-001ELECTRICAL BASIC DESIGN GUIDELINES


Dry type transformers in a systemWhat can ABB do ?

Provide the best technologies available conforming with Petrobras 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 voltage drop during DOL motor starts)

Harmonic calculations (THD)

Provide transformers which offers the best possible cancellation configuration with the VFD

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

Up to 1/18 reduction of inrush current !


Dry type transformers in a systemConfiguration of converter duty transformers

Distortion with 6 pulse




Dry type transformers in a systemSimple pre-magnetizing system

T1

C2

C1

C3

T2 440 V

Simple and cost effective if back up supply available

Integrated in transformer enclosure

In Switchgear

Separate assembly

Figure of pre-magnetizing system in a essential mode drilling transformer to 690 V drilling drive system from weak 440V emergency supply network


Dry type transformers in a systemPeregrino WHP’s

Total 10 units for water injection, booster and production pumps

ACS 1000i

24 pulse integrated dry type transformer

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