Quit 1 TRANSFORMER PROTECTOR 4 th UPDEA SCIENTIFIC COMMITTEE March 12, 2008 Transformer Operations &...

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Quit 1 TRANSFORMER PROTECTOR 4 th UPDEA SCIENTIFIC COMMITTEE March 12, 2008 Transformer Operations & Failure Avoidance Rui Da Silva, SERGI FRANCE

Transcript of Quit 1 TRANSFORMER PROTECTOR 4 th UPDEA SCIENTIFIC COMMITTEE March 12, 2008 Transformer Operations &...

Page 1: Quit 1 TRANSFORMER PROTECTOR 4 th UPDEA SCIENTIFIC COMMITTEE March 12, 2008 Transformer Operations & Failure Avoidance Rui Da Silva, SERGI FRANCE.

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TRANSFORMER PROTECTOR

4th UPDEA SCIENTIFIC COMMITTEE March 12, 2008

Transformer Operations & Failure Avoidance

Rui Da Silva, SERGI FRANCE

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TRANSFORMER PROTECTOR

Introduced Power Factor Testing 1929

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What We Are Trying To Avoid

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TRANSFORMER PROTECTOR

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Number of Transformer Events/Yr

0

5

10

15

20

'91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01

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Data Sources (1)Insurance - Carrier & Industry Sources

AllianzMunich ReSwiss ReLloyds SyndicatesFactory Mutual Research & EngineeringFM Global, previouslyAllendale MutualArkwright MutualProtection MutualAIG / Hartford Steam Boiler Inspection and InsuranceRoyal InsuranceIndustrial Risk InsurersAmerican Insurance Association

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Data Sources (2)Power Industry Sources

Edison Electric Institute McCoy Power Reports INPO Operational Reliability Program IEEE RAM Comm (Reliability Availability & Maintainability Utility Data Institute Electric Power Reserch Institute American Power Conference, extracts 1990 to 2001 Intl. Joint Power Conference, extracts 1989 to 2001 MFR’s : GE, Alstom, ABB, Siemens, Westinghouse

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0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2 8 14 20 26 32 38 44 50 56 62 68 74

Age

Haz

ard

Fu

nct

ion

Aging Forecast

latest forecast model ….. ff(t) (t) = = A + A + e e tt

1 + µ1 + µ e e t t

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Insurer’s Exposure to Losses

Civil

63%18% 8%4%<2%

SYSTEMS &COMPONENTSSTART

5%

10%

32%

18%

15%

MechanicalCompletion

Testing OperationalPerformanceErection

10% Rise

= 15 Year History

= 2002/2006

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TRANSFORMER PROTECTOR

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Forced Outage (Unplanned Maintenance/Repair Times)

Time-to-Repair Distributions for Minor, Major and Catastrophic Events

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

1 10 100 1,000

Time to Repair, Hours

Pro

ba

bil

ity MINOR

(5 hr/ event)MAJOR

(55 hr / event)

Catastrophic(230 hr/event)

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US Power Plant Fatalities

0

2

4

6

8

10

12

14

1971 1976 1977 1989 1992 1993 1994 1995 1999 2000

Fatalities due toExplosions and Fires

Total: 35 people

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Transformer Failure Modes

Thermally induced Electrically Induced Mechanically Induced

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Transformer Failure Modes

ElectricallyInduced

• Over Voltage• Surges• Partial

Discharge• Static

Electrification

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Transformer Failure ModesMechanically Induced

Conductor Tipping

Conductor Telescoping

Hoop Buckling

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Mechanical Failure

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Transformer Failure Modes

Thermally Induced Overloading Failure of cooling system Blockage of axial spaces Over-excitation (over-voltage or

under-frequency)

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Cause of Failures

20 years of claims

Insulation issues 18%

Electrical Disturbances

29%

Maintenance issues13%

Lightning16%

Loose Connection

13%

Moisture7%

Overload2%

Other2%

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TRANSFORMER PROTECTOR

Types of Transformers

Distribution, for residential serviceGenerator Step-up TransformersAutotransformersMulti-winding transformers(> 2 windings)Rectifier Transformers--SmeltersFurnace Transformers--Steel MillsInverter Transformers-DCConverter Transformers-DCRegulating Transformers--Voltage, Current Phase, AngleInstrument Transformers--Voltage/CurrentOther

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Generator Step-Up Transformers(GSU’S)

Usually (90%+) two-winding transformersLarge KVA (50000kVA and higher, up to 1,300,000 kVA)Used at Power Plants

Fossil-Coal/Oil/GasNuclearHydro

Raises the voltage from the generator voltage (12-26 kV)to the Transmission System Voltage (69-765kV)to allow efficient transmission of power from the energy source to the load.

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Autotransformers•Primary use is to connect two transmission systems of different voltages•The two systems must by Y-connected and of the same phasing and polarity•“Short-ended” autos (re 200/190 kV) or “long-ended” (200/20 kV) are not practical.•Autotransformers can step voltage up or down.

Typical voltage ratings of Autotransformers in NA

138/69 kV230/115 kV345/138 kV345/230kV500/230kV500/345kV

765/345 kV765/500 kV765/138 kV500/161 kV

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TRANSFORMER PROTECTOR

►How to protect your investment?

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TRANSFORMER PROTECTORTransformer Specification

Evaluate system requirements Evaluate transformer requirements Evaluate client standards Review or create entire specification Design Review – At Factory Drawing & Materials Review Scheduling Coordination Core & Coil – Pretank Inspection Factory Test

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Core Form vs Shell Form Transformers

Core FormRound Coils( Cylinder)Coils Wrapped on a tube then

loaded on coreCore stacked in legs and then

windings are placed over them

Vertical Core LegsWindings Concentric around

each otherMajority of Transformers in the

world

Shell FormFlat Coils in rectangular shapeCoils stacked into groupsInterleaved windingsCore stacked around the coilsCore is HorizontalStronger under short circuitGenerally more expensiveMajor advantages in GSU’sABB (Cordoba), IEM (Mexico), Schneider (France), Mitsubishi(Japan), Hyosung (Korea),GE (UNITED STATES!)

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Basic ConstructionBasic Construction

CORE FORMSHELL FORM

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Core Form Construction

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Shell Form Construction

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Single Phase vs Three Phase Units

Three Phase Most Economical Smallest footprint Simplifies station design Most Common

Single Phase- Min of 3 units- Easier to spare (4th Tx)- Greater

Reliability/Availability- 3-Phase too large to ship- Larger footprint- More Expensive

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TRANSFORMER PROTECTORField Testing - Oil Diagnostics

OIL Dissolved Gas Analysis (DGA) Profile (Main Tank, OLTC) Furan Analysis Moisture Content Dielectric Strength Oil Condition Inhibitor Content Metals Corrosive Sulfur Acidity Degree of Polymerization

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TRANSFORMER PROTECTORThe different components of the protection

1. Depressurization Set

2. OLTC Depressurization Set

3. Oil-Gas Separation Tank

4. Explosive Gas Elimination Pipe

5. Cabinet

6. Explosive Gases Evacuation

7. Conservator Shutter

To create an evacuation opening before the dynamic pressure becomes uniform static pressure

5

62

4

7

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1/ The dynamic pressure peak travels at the speed of sound inside oil

2/ Rupture of the disk, depressurisation, evacuation of the oil-gases mixture

4/ Nitrogen injectionN2

3/ Opening of the air isolation shutter5/ Explosive gases production is stopped after 45 min

THE TRANSFORMER PROTECTION : OPERATION

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TRANSFORMER PROTECTORCOMPUTATIONAL INVESTIGATIONS

Pressure Wave Propagation

Gas and Oil Behaviours

Complex Geometry

Compressible Two-Phase Flow Model

EM, thermal, viscosity, gravity

Numerical Tool Finite Volume Method on Unstructured mesh

Numerical Tool Validation

2002 and 2004 Tests on Transformers

Extrapolation to Transformers

>100MVA

Protection Validation

High Fault Currents

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Energy Transfer

Modelling

Gravity Effect

Modelling

Hydro Effect

Modelling

Viscous Effect

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PeP 1Equation of state :

Physical Modeling

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TRANSFORMER PROTECTORAny Questions?