sttpgaaa31e - tp presentation for bdam - copy
TRANSCRIPT
During a transformer short circuit, the TRANSFORMER PROTECTOR is activated within milliseconds by the firstdynamic pressure of the shock wave, avoiding transformer explosions before static pressure increase
TRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
www.transproco.com
TRANSFORMER PROTECTOR Presentation
TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 2
NFPAThe TRANSFORMER PROTECTOR is now recommended for all Power Plants and Substations in the National Fire Protection Association 2010 edition of:• NFPA 850 (Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations),• NFPA 851 (Recommended Practice for Fire Protection for Hydroelectric Generating Plants).
The introduction of the 2010 edition of NFPA 850 & NFPA 851 stands : “Fast depressurization systems have been recognized, and recommendations for the use of these systems are now included”
“Fast depressurization system: a passive mechanical system designed to depressurize the transformer a few milliseconds after the occurrence of an electrical fault”
More details later in the presentation or
Just click here
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 3
1. Transformers are very dangerous
• Examples of explosions
• Conventional protections
• The answer
1. Transformers are very dangerous
TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 4
Danger :
• The whole power plant (1,350MW) was out of service for 4 months.
• The damaged section (450 MW) was out of service for 13 months.
• 2 people were badly burned.• Fire extinguishing systems did not
work.• Security fire doors were too slow.
Transformer explosion in substation :
Power transformers are very dangerous
Transformer explosion in substation
•Large quantity of oil in contact with high voltage elements•No international security norm for transformers
1. Transformers are very dangerous Examples of explosions
Click on picture to watch video
TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 5
Other explosion examples
Krümmel Nuclear Power Plant, GermanyJune 2007, still not restarted !
Cost: 1 Million USD / day !
3Transformer explosions lead to:
• Huge fire
• Plant outage
• Huge costs : hundreds millions USD
• Ruin company reputation
• Environmental pollution
• Human life risks
1. Transformers are very dangerous Examples of explosions
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 6
1. Transformers are very dangerous Conventional protections
a) South Bend, Indiana , USA, 1999
Efficiency ?Corrective Means
• Firewalls • Fire extinguishing systems
Limit fire propagation induced by the explosion Fire propagated from one transformer
to the other
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 7
1. Transformers are very dangerous Conventional protections
b) Venice Plant, Illinois , USA, 2000
Efficiency ?Corrective Means
Solution : Preventing transformer explosion to avoid fire
• Firewalls • Fire extinguishing systems
Limit fire propagation induced by the explosion
Fire propagated to the whole plant: All 9 transformers caught fire despite fire
walls and fire extinguishing systems (cost: USD 230 millions)
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 8
1. Transformers are very dangerous Conventional protections
All exploded transformers
were equipped with these
devices
Efficiency ?Preventive Means
• Circuit breakers
• Buchholz Relay
• Sudden Pressure Relay
• Gas Monitoring
• Pressure Relieve Valve
Solution : The protection must act faster !
2
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 9
1. Transformers are very dangerous The answer
During a short circuit, the TP is activated within milliseconds by the first dynamic pressure peak of the shock wave, avoiding explosions by preventing static pressure increase.
The TP key of success
The TRANSFORMER PROTECTOR (TP)The TP depressurizes transformers within milliseconds
avoiding explosion and subsequent fire.
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 10
2. Preventing transformer explosion: the TP principle
• Transformer explosion process
• TP strategy to prevent explosion
• TP operation
• TP standard configuration
• TP operation movie
2. Preventing Transformer Explosion: The TP Principle
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 11
Why do transformers explode ?
Dielectric oil insulation rupture
Electrical arc
Oil vaporization
Local dynamic pressure increase
First dynamic pressure peak propagates
Dynamic pressure peak reflects off walls
Static pressure increases
Tank rupture & Fire
2. Preventing transformer explosion: the TP principle Transformer explosion process
TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 12
How to break that sequence?
Dielectric oil insulation rupture
Electrical arc
Oil vaporisation
Local dynamic pressure increase
First dynamic pressure peak propagates
Dynamic pressure peak reflects off walls
Static pressure increases
Tank rupture & Fire
2. Preventing transformer explosion: the TP principle Prevention strategy
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 13
Activation within milliseconds by the first dynamic pressure peak
Quick Oil Evacuation
Tank depressurization
Prevents the explosion
How to break that sequence?
Dielectric oil insulation rupture
Electrical arc
Oil vaporisation
Local dynamic pressure increase
First dynamic pressure peak propagates
Dynamic pressure peak reflects off walls
2. Preventing transformer explosion: the TP principle Prevention strategy
TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 14
2. Preventing transformer explosion: the TP principle TP operation
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 15
2. Preventing transformer explosion: the TP principle TP operation
• Electrical arc• Pressurized gas bubble• Dynamic pressure peak propagation
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 16
2. Preventing transformer explosion: the TP principle TP operation
Quick oil evacuation generating fast depressurization of the tank (within milliseconds)
TP Activation1
• Electrical arc• Pressurized gas bubble• Dynamic pressure peak propagation
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 17
2. Preventing transformer explosion: the TP principle TP operation
• Explosive gases remain• Melting parts of the windings are still emitting gases
Quick oil evacuation generating fast depressurization of the tank (within milliseconds)
TP Activation1
• Electrical arc• Pressurized gas bubble• Dynamic pressure peak propagation
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 18
2. Preventing transformer explosion: the TP principle TP operation
Evacuation of the explosive gases until the melted parts are cooled down (~ 45 mn)
Injection of Inert Gas2
Quick oil evacuation generating fast depressurization of the tank (within milliseconds)
TP Activation1
• Explosive gases remain• Melting parts of the windings are still emitting gases
• Electrical arc• Pressurized gas bubble• Dynamic pressure peak propagation
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 19
2. Preventing transformer explosion: the TP principle TP operation
Transformer safe and ready for repair
Quick oil evacuation generating fast depressurization of the tank (within milliseconds)
TP Activation1
Evacuation of the explosive gases until the melted parts are cooled down (~ 45 mn)
Injection of Inert Gas2
• Explosive gases remain• Melting parts of the windings are still emitting gases
• Electrical arc• Pressurized gas bubble• Dynamic pressure peak propagation
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 20
2. Preventing transformer explosion: the TP principle TP standard configuration
Standard TRANSFORMER PROTECTOR (TP)
6
2
1 4
1. Vertical Depressurization Set (VDS)
2. OLTC Depressurization Set (OLTC DS)
3. Slice Oil-Gas Separation Tank (SOGST)
4. Explosive Gases Evacuation Pipe (EGEP)
5. Air Isolation Shutter
6. TP Cabinet
7. Inert Gas Injection Pipe (IGIP)
The ComponentsTP Components
7
3
5
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 21
2. Preventing transformer explosion: the TP principle TP operation movie
TP Operation Movie
Click on picture to watch video
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Ref: StTPgaaa31eTRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
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3. Physical Explanations and Testing of the TP Experimental tests: general overview
Two main test campaigns
ConclusionDuring the 62 tests, the TP always saved transformers from explosion without permanent tank deformation
• 2002: 28 tests by EDF (Electricité de France) on small transformers
• 2004: 34 tests by CEPEL (HV independent lab.) on large transformers (8.4m – 26ft long)
• Principle: electrical arcs were ignited inside transformers tanks equipped with a TP
Click on pictures to watch videos
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Ref: StTPgaaa31eTRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
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3. Physical Explanations and Testing of the TP Vaporization saturation process
SKIP
1st key phenomena: oil vaporization & arc creation – video1
Arc movie during the EDF testsHigh speed camera 3000 fps
Chronology
0 ms : Start of applied current
3.66 ms : Bubble generation
4 ms : Bubble volume = 9 cm3, 0.5 in.3
4.33 ms : Bubble volume = 60 cm3, 3.7 in.3
4.66 ms : Bubble volume = 97 cm3, 5.9 in.3
5 ms : Bubble volume = 190 cm3, 11.6 in.3
5.33 ms : Bubble volume = 299 cm3, 18.2 in.3
5.66 ms : Bubble volume = 399 cm3, 24.3 in.3
6 ms : Bubble volume = 568 cm3, 34.7 in.3
6.33 ms : Electrical arc fully developed - plasma
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Ref: StTPgaaa31eTRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
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3. Physical Explanations and Testing of the TP Dynamic / static pressure
• Spatially uniform all over the tank• Progressive, slow increase • Oil behaves as an incompressible
media• Max withstand ~1 bar – 15 psi (gauge)
• Very localized and moving in the tank• Propagates quickly within the tank• Oil behaves as a compressible media• Tank can resist 13 bar – 190 psi
(gauge)
The tank does not explode The tank explodes
Dynamic PressurePressure gradients over 25 bar/s – 360 psi/s
Static PressurePressure gradients under 25 bar/s – 360 psi/s
How does the PRV react to dynamic
pressure ?
Click here
Pressure gradients up to 5000 bar/s – 72000 psi/s
Propagation speed: 1200 m/s – 4000 ft/s
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Ref: StTPgaaa31eTRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
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3. Physical Explanations and Testing of the TP Influence of the TP
a) No static pressure The quick oil evacuation generates rarefaction waves that depressurizes the tank before static pressure builds up.
0 ~10 ms
Arc occurrence
TP is activated
Tank is depressurized
~80 ms
Dyn. pressure travelling
Oil evacuation
Click on picture to watch videoThe DS is activated within milliseconds by the first dynamic pressure peak and evacuates pressure while tank structure inertia to rupture is much higher.
The breaking section to open the precut Rupture Disk at the dome is more than 50 times less than the section of tank bolts.
Very small section to break to activate TP
6th key phenomena: the TP depressurizes tanks preventing explosion6
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Ref: StTPgaaa31eTRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
50 ms
30 ms
10 ms
4 ms
1 ms
100 ms
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50 ms60 ms70 ms80 mst =
Static pressure builds up
Dynamic pressure reach more than 9 bar – 130 psi (gauge) in a bushing
Reflects off the walls and creates complex pressure waves
Gas bubble under pressure
The first dynamic pressure peak propagates
Static pressure stabilizes at 5.5 bar – 80 psi (gauge)
100 ms
Transformer explodes
3. Physical Explanations and Testing of the TP Simulation tool – 200 MVA transformer – no protection
11 MJ electrical arc
Max. static withstand limit pressure of transformer tanks :
1.2 bar – 17 psi (gauge)
Pressure (gauge) (psi) (bar)
without TP
Ref: StTPgaaa31eTRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
1 ms
27
70 ms80 ms100 mst =
After 60 ms
11 MJ electrical arc
Gas bubble under pressure
150 ms
3. Physical Explanations and Testing of the TP Simulation tool – 200 MVA transformer – with TP
4 ms
10 ms The dynamic pressure peak activates the TP
The first dynamic pressure peak propagates
15 ms
30 ms
60 ms
The tank depressurizes
Rarefaction waves are spread in the tank
The tank is fully depressurized
without TP
with TP
• without TP, static press. = 5.5 bar – 80 psi
Pressure (gauge) (psi) (bar)
• with TP, static pressure = atm. pressure
without TP
with TP
Ref: StTPgaaa31eTRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
after 120 ms
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3. Physical Explanations and Testing of the TP Simulation tool – Real case study – 400 MVA transformer
• Without TP, the max. pressure is 14 bar – 200 psi and the static pressure builds up at around 7 bar – 100 psi.
the tank explodes
• With TP, the first dynamic pressure peak activated the TP within milliseconds before static pressure is built up.
the tank is safe
with TPwithout TP
Pressure (gauge) (psi) (bar)
after 120 ms after 120 ms
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 29
4. TP Technical Description Retrofitting on existing transformers
The TRANSFORMER PROTECTOR is easily retrofitted without tank machining by using the existing interfaces
1. Depressurization Set: Cover and Side Manholes, Pressure Relief Valves and Existing Valves can be used for the adaptation
SKIP
Retrofitting on existing transformers
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e
Retrofitting on existing transformers
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4. TP Technical Description Retrofitting on existing transformers
The TRANSFORMER PROTECTOR is easily retrofitted without tank machining by using the existing interfaces
1. Depressurization Set: Cover and Side Manholes, Pressure Relief Valves and Existing Valves can be used for the adaptation
2. Inert Gas Injection: Existing Valves for oil sampling and draining can be used to retrofit the inert gas injection
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 31
5. References Financial benefit
The TP Financial Benefit is very high
The Protection Financial Benefit (PFB) is calculated as :PFB = CTC / (MLEB – LEA)
For corporate risk managers and insurance, if:• PFB < 1 %, the protective technology is highly recommended• 1% < PFB < 4%, insurance companies adjust their rates and premiums
Analyses showed that the TP Financial Benefit varies from 0.015 % to 0.06 % !
When an incident occurs, the TP compensates several thousand times the investment
• CTC (Cost To Complete) : complete price of the protection (including erection and tests)• MLEB (Maximum Loss Expectancy Before): cost of the worst recorded incident before
installing a protection• LEA (Loss Expectancy After): evaluation of the damage cost of the worst recorded incident
with the chose protection after installation
Extract from “Transformer Explosion and Fire Incidents, Guideline for
Damage Cost Evaluation, Transformer Protector Financial Benefit”
Available on request
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e
Generation Transmission Distribution
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5. References Sold TP
More than 1.400 TP sold since 2000
Every kind of oil-filled transformers (above 1 MVA)
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 33
5. References End users
More than 106 companies in 53 countries:
• Australia: Delta Electricity• Brazil: Abengoa, Tractabel,• France: EDF• Germany: Vattenfall
•Jordan: JEPCO, NEPCO•Mexico: CFE•Namibia: NamPower•Russia: Rusgidro, FNK
•Qatar: Kahramaa, Qatar Petroleum•South Africa: Eskom, City Power•Spain: Metro de Madrid•USA: PG&E, Sunflower Electric
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 34
5. References NFPA
• Standard NFPA 850 (Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations)
• Standard NFPA 851 (Recommended Practice for Fire Protection for Hydroelectric Generating Plants)
The NFPA recommends the TP
In the introduction of NFPA 850 and 851:
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 35
5. References NFPA
Definition of “fast depressurization system” by the NFPA:
• Standard NFPA 850 (Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations)
• Standard NFPA 851 (Recommended Practice for Fire Protection for Hydroelectric Generating Plants)
The NFPA recommends the TP
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 36
5. References NFPA
Explanation of the operation by the NFPA:
• Standard NFPA 850 (Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations)
• Standard NFPA 851 (Recommended Practice for Fire Protection for Hydroelectric Generating Plants)
The NFPA recommends the TP
Documents available on
request
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 37
FM Global : Certification under progress
NFPA : TP is recommended in the standards 850 & 851 and in the NFPA Fire Handbook 2002 & 2008
EDF (Electricité de France) and CEPEL (Brazil) laboratories TP tests validation
Active participation in the Power Transformer Subcommittee (tank rupture mitigation taskforce)
Various IEEE Conferences
Active participation in the A2 Study Committee – Transformers (transformer fire safety practices WG)
Various Cigré Conferences
5. References Valorization or certification organisms
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 38
5. References Successful activations
• Romania (TransElectrica), • Philippines (Transco), • Botswana (Botswana Power Corporation),• Activation in Pakistan, Mexico (3) and Romania under
process
The TP saved transformers, successful activation certificates from:
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e
with TP without TP
after 100 ms
Pressure (gauge) (psi) (bar)
39
Conclusion
Brazil Germany France
• The NFPA Fire Handbook emphasizes the TP technology• Several successful activations• More than thousand TP sold all over the world (USA, Europe, Middle East…)
3. The TP is a recommended solution
• Principle: No Actuator !The TP is activated by the first dynamic pressure peak generated by the arc, avoiding the explosion by preventing static pressure increase
• Efficiency demonstrated by experimental tests & numerical simulations
2. The TRANSFORMER PROTECTOR prevents the explosion
• Explosions are more and more frequent• Dangerous, expensive, polluting, hurt reputation…• Conventional corrective means do not prevent explosion (fire extinguishing systems,
firewalls)• Conventional preventive means are not efficient (circuit breakers, buchholtz, PRV...)
1. Power transformers are very dangerous
39
During a transformer short circuit, the TRANSFORMER PROTECTOR is activated within milliseconds by the firstdynamic pressure of the shock wave, avoiding transformer explosions before static pressure increase
TRANSFORMER PROTECTOR
The Only Solution Against Transformer Explosion
www.transproco.com
TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 41
5. References CEPEL (Brazilian independent laboratory)
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 42
3. Physical Explanations and Testing of the TP TP – PRV reaction to dynamic pressure
TRANSFORMER PROTECTOR Pressure Relieve Valve (PRV)
How does the PRV react to dynamic pressure ?
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e 43
• Spring inertia to open: 5 ms• PRV reacts to dynamic pressure for
0.1ms PRV diameter: 15 cm - 6 in. Dyn. press. speed: 1200 m/s – 4000 ft/s
• activated by dynamic pressure peak • depressurizes the tank within
milliseconds• prevents static pressure increase
The tank does not explode Dynamic pressure peak too
fast to activate the PRV
TRANSFORMER PROTECTOR Pressure Relieve Valve (PRV)
0.1 ms
3. Physical Explanations and Testing of the TP TP – PRV reaction to dynamic pressure
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e
3. Physical Explanations and Testing of the TP PRV reaction for lower pressure gradient
Even for lower pressure gradients, the PRV is not adapted• 1st step : spring inertia is 5 ms• 2nd step: when the PRV is 50% open, only 15% of the section is used to
evacuate the oil
Evacuation Section only 15% when half open
0%
50% Spring inertia 5 ms
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e
3. Physical Explanations and Testing of the TP PRV reaction for lower pressure gradient
Even for lower pressure gradients, the PRV is not adapted• 1st step : spring inertia is 5 ms• 2nd step: when the PRV is 50% open, only 15% of the section is used to
evacuate the oil• 3rd step: oil has to make a “U turn” to escape, the evacuation is slowed
down• 4th step: even when the PRV is fully opened, only 80% of the section is used
Evacuation SectionOnly 80% of 6’’ when
fully open
0%
50%
100%
U turn for the oil evacuation
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TRANSFORMER PROTECTORThe Only Solution Against Transformer Explosion
1/ Transformers explosions2/ TP principle3/ Physical explanations4/ Technical description5/ TP References
Ref: StTPgaaa31e
3. Physical Explanations and Testing of the TP PRV reaction for lower pressure gradient
What is the use of the PRV ?
• PRV is not adapted for low impedance fault (arcing)• PRV is designed for slow pressure increase to relieve low static
overpressure High impedance fault Low temperature increase Very slow gas creation …
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