Arild Furnes,ATPA OGP/Petrobras workshop, Dry type transformers-ideal for FPSO - Transformers for electrical and drive systems

Transcription

1 Arild Furnes,ATPA OGP/Petrobras workshop, Dry type transformers-ideal for FPSO - Transformers for electrical and drive systems September 24, 2009 Slide 1

2 Transformers for Ships and Offshore - Standards IEC Electrical installations in ships, Part 303 equipment - Transformers for power and lighting IEC Mobile and fixed offshore units, Part 3 equipment - Clause 5 -Transformers for power and lighting Both refer to general transformer standards IEC (all types) and IEC (Dry type transformers) Preferably air cooled dry type Liquid-immersed transformers preferably hermetically sealed type, no spilling of liquid September 24, 2009 Slide 2

3 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, flexible connections EX-classified zones = specifically designed transformers Materials to be used Self extinguishing High tracking index Halogen free September 24, 2009 Slide 3

4 Transformers for Ships and Offshore - Standards Differences to be noticed to on shore applications 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 September 24, 2009 Slide 4

5 Transformers for Ships and Offshore - Standards Dry transformers-technologies Dry type transformers IEC 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 ( m) critical If the LI level is not mentioned, you may be getting the lower one ie list 1 Classification rules have no impulse voltage requirements Area to be improved Dry type transformers cannot be installed without extensive measures on Explosion Hazard Zones at all, but must be installed on Safe Areas Temperature hot spots on coils, Sparking and charging at switching on September 24, 2009 Slide 5

6 Transformers for Ships and Offshore - Standards Dry transformers-technologies Dry type transformers IEC Encapsulated type = resin encapsulated (cast resin or filament wound 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 on the transformer coils, but note that in the standard no switching overvoltage is considered (known to be a problem with vacum breakers 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 designs Climatic class C1,C2 For ships minimum C1 (-5 C) is sufficient For scandinavian Yards C2 (-25 C) is necessary while building ships September 24, 2009 Slide 6

7 Most common variants of dry type transformers Other important considerations Two dry type transformers in common enclosure for 24 pulse rectifer duty. Petrobras requires dedicated enclosure as per today. Rectifier duty. Derating approx. 20 % with 6 puls diode rectifier. Primary phase shift removes possibility for tapping, no-load voltage needs to be carefully selected 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, bigger unit not to exceed thermal limits September 24, 2009 Slide 7

8 Most common variants of dry type transformers Other important considerations Vacum cast coil Both size and audible noise can 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 physical dimensions September 24, 2009 Slide 8

9 Most common variants of dry type transformers Dry VPI open wound with paper Petrobras specifications in general calls for resin encapsulated types Up to approx 12 MVA 15 kv Several cooling options available Both Cu and Al windings available Cost efficient 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 September 24, 2009 Slide 9

10 Most common variants of dry type transformers Vacum Cast Coil Up to approx 30 MVA 50 kv Several cooling options available Both Cu and Al windings available Manufactured by all major suppliers Classes: E2, C2, F1 Partial discharges: <10 pc Insulation : 155ºC (F), 180ºC (H) Design Temperature: 40 ºC September 24, 2009 Slide 10

11 Most common variants of dry type transformers Resibloc 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 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. September 24, 2009 Slide 11

12 MTBF Resibloc Transformers 433 years! September 24, 2009 Slide 12

13 Resibloc Transformers Technology highlights September 24, 2009 Slide 13

14 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 % increase Practically maintenance free September 24, 2009 Slide 14

15 Why use dry type transformers on FPSO Areas 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. September 24, 2009 Slide 15

16 Why use dry type transformers on FPSO Liquid filled application FPSO outside West Africa. Multi Phase Pump Power Control Module with drives inside Roof of FPSO E-house Compact liquid filled Corrugated tank design Conservator type design Zone 1 or 2 outdoor September 24, 2009 Slide 16

17 Why use dry type transformers on FPSO Liquid 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. September 24, 2009 Slide 17

18 Why use dry type transformers on FPSO Liquid 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 September 24, 2009 Slide 18

19 Dry type transformer with water cooling AF/WF Increasing interest in the offshore and ship market No liquid carrying pipe allowed. Clause 1.4 in Petrobras I-ET PCI- 001ELECTRICAL BASIC DESIGN GUIDELINES 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 September 24, 2009 Slide 19

20 Dry type transformers in a system What 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! September 24, 2009 Slide 20

21 Dry type transformers in a system Configuration of converter duty transformers Distortion with 6 pulse Distortion with 12 pulse Distortion with 24 pulse September 24, 2009 Slide 21

22 Dry type transformers in a system Simple pre-magnetizing system Simple and cost effective if back up supply available Integrated in transformer enclosure In Switchgear Separate assembly C2 440 V C1 T2 C3 Figure of pre-magnetizing system in a essential mode drilling transformer to 690 V drilling drive system from weak 440V emergency supply network T1 September 24, 2009 Slide 22

23 Dry type transformers in a system Peregrino WHP s Total 10 units for water injection, booster and production pumps ACS 1000i 24 pulse integrated dry type transformer September 24, 2009 Slide 23

24 September 24, 2009 Slide 24