Hussam al amin retrofilling with ester based transofmer dielectric fluid to improve fire safety

Copyright 2011 M&I Materials Ltd. Products of M&I Materials Ltd.

Retrofilling with Ester Based Transformer Dielectric Fluid to Improve Fire Safety, Moisture Tolerance and

Environmental BehaviourMarch 2011


Copyright 2011 M&I Materials Ltd. www.midel.com

Transformer Fluids Introduction

Mineral OilSynthetic

EsterSilicone Liquid

Source Crude OilSynthetic Product

Synthetic Product

Typical Fire point

170°C 316°C >350°C

Fully Biodegradable

No Yes No

Moisture Tolerance

Poor Excellent Poor


Transformer Fluids Introduction• Mineral oil fires are common

occurrence • Risk to human life • Extremely costly in terms of

damage and clean up (£m’s)• Knock on effects – e.g.

Blackouts • Down-time cost • Transformer replacement • Increased insurance

premiums • Damage to reputation


Typical Flash and Fire PointFlash Point• Defined as temperature at which vapour ignites, but will not sustain burning

when flame is removed

Fire Point• Defined as temperature at which vapour ignites and sustains burning for at

least 5 seconds when source of ignition is removed

Fluid Flash Point (ISO 2719 - Pensky)

Fire Point (ISO 2592 - COC)

MIDEL 7131 260°C 316°C

Mineral Oil 150°C 170°C

Silicone Liquid 260°C >350°C


Ignition Resistance

Mineral Oil 3 mins

MIDEL 7131 3 mins

Mineral Oil 4 mins

MIDEL 7131 70 mins


Insurance Advice

• FM Global® loss prevention datasheet 5-4 transformers

• Spacing between transformers

TransformerMin. Spacing

2,000litres 40,000litres

Mineral Oil 7.6m 15.2m

Approved Less Flammable Fluid

1.5m7.6m

Approved Transformer or Equivalent

0.9m 0.9m


Comparative Biodegradation Rates

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30

Time (Days)

Bio

de

gra

da

tio

n (

%)

MIDEL 7131

Mineral Oil

Silicone Liquid


Containment Requirements

• FM Global® guidance

• Much larger amount of fluid permitted before containment is required

Fluid ClassificationVolume Requiring Containment

(litres)

Mineral Oil >1,900

Approved less flammable fluid >5,000

Approved biodegradable fluid >10,000


Moisture Saturation Comparison

FluidSaturation Limit

@ 20°C

MIDEL 7131 2700ppm

Mineral Oil 55ppm

Silicone Liquid 220ppm


Breakdown Voltage vs. Relative Moisture

0

10

20

30

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60 70 80 90 100

Relative Moisture Content (%)

Bre

akd

ow

n V

olt

age

(kV

) MIDEL 7131

Mineral Oil

Silicone Liquid

IEC Breakdown Voltage Limit

Ref: Prof. S. Tenbohlen Stuttgart


Moisture Uptake Comparison 90% Humidity

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30

Time (Days)

Rel

ativ

e M

ois

ture

Co

nte

nt

MIDEL 7131

Mineral Oil

Critical Moisture Level

Ref: I. Fofana University of Quebec


Condensation in Wet Transformers

Temp. 90°C

Saturation Limit

Transformer Running High LoadMIDEL 7131

Moisture 700ppm

<12% saturated

OK

Mineral Oil

Moisture 65ppm

<15% saturated

OK

Temp. 20°C

Saturation Limit

Transformer Shutdown Mineral Oil

Moisture 65ppm

118% saturated

CONDENSATION

MIDEL 7131

Moisture 700ppm

26% saturated

OK


Mineral Oil Low Temperature Breakdown

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60 70 80 90 100

Temperature (°C)

Bre

akd

ow

n V

olt

age

(kV

)

10ppm

20ppm

40ppm

Ref: H. Borsi Schering Institute


Synthetic Ester Low Temperature Breakdown

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 100

Temperature (°C)

Bre

akd

ow

n V

olt

age

(kV

)

20ppm

80ppm

200ppm

500ppm

Ref: H. Borsi Schering Institute


Corrosive Sulphur• MIDEL 7131 does not contain corrosive sulphur

• Mineral oil source of corrosive sulphur compounds

• Causes copper sulphide deposit on paper and copper windings

• Identified as cause of failure of power transformers

• MIDEL 7131 independently tested to ASTM D 1275 B and IEC 62535

• MIDEL 7131 was found to be non-corrosive in both tests

• MIDEL 7131 tested for DBDS, none found


Why Retrofill with MIDEL 7131?• Retrofilling is the replacement of the fluid in the transformer

• Increased Fire Safety

• Significantly improves fluid fire point

• High Performance

• Provides moisture tolerance

• Reduces maintenance

• MIDEL 7131 is very oxidation stable, suitable for breathing transformers

• Greater environmental protection

• Accelerates biodegradation rate


Retrofilling Case Study – SEWA 2009• Sharjah Water and Electricity

Authority chose MIDEL 7131 for a retrofilling pilot study

• Sharjah Gold Souk (tourist attraction), UAE

• Mineral oil transformer, 1500kva, 11/0.433kV, 2001

• Densely populated area, running at high temperatures – deemed high risk

• Initial test results excellent & analysis to take place over next few years to assess progress


Retrofilling Experience - Vattenfall• Large utility with operations throughout Europe• In Berlin: Started retrofilling 1992 in high risk areas• 500 transformers retrofilled with ester between 1992 -1994• From 1994, on average 10 transformers per year retrofilled• All new distribution transformers in risk areas are ester filled• 1,900 transformers in total with ester


Vattenfall Results – Pilot Phase


Vattenfall Results – Long Term


Retrofilling Field Trial - Devonport• Shipyard in South of England

• Ex Ministry of Defence

• 800 kVA, 30 year old transformer

• Joint retrofilling trial in 2004

• Wet transformer, out of service


Retrofilling Field Trial - Devonport• Transformer was out of service due to low insulation resistance

• Retrofilled with MIDEL 7131

• Insulation resistance increased and transformer back in service

Before

(Mineral oil)

After

(MIDEL 7131)

Breakdown Voltage 22kV >65kV

Moisture Content 51.4ppm 400ppm

Core Insulation Reading

<20M 80M


Devonport Breakdown Voltage Results

0

10

20

30

40

50

60

70

80

90

100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Time (Years)

Bre

akd

ow

n V

olt

age

(kV

)

IEC 61203 Minimum Limit for Synthetic Esters


Thank-you for listeningHussam Al-Amin – Business Development Manager Tel: +44 161 864 5495 Email: [email protected]

Hussam al amin retrofilling with ester based transofmer dielectric fluid to improve fire safety

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