extreme performance: increasing resilience and mitigating risk - climatic tests for transformers...
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Presentation about: Extreme performance Increasing resilience and mitigating risk: Climatic tests for transformers integration with offshore wind powerTRANSCRIPT
Extreme performance Increasing resilience and mitigating risk:
Climatic tests for transformers integration with offshore wind power
Pieter Jan Jordaens Business development & Innovation [email protected]
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Content
Introduction Drivers for wind energy R&D Technological Evolution – technical challenge Risk mitigation pathways
Requirements with regard to sites: focus cold climate Testing & validation: focus cold climate
Wind turbine testing in general Climate chamber testing of transformers Case study in the climatic test chamber: focus cold climate
Liquid filled transformers Cast resin transformers
Conclusion
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Introduction
Non-profit Belgian technology centre Mission: to support companies with implementing
technology innovations 160 engineers and scientists Multidisciplinary R&D and innovation projects
Mainly for Belgian companies (SME & Large) Also shared R&D projects with EU companies
High tech R&D infrastructure
Competences
High-tech Test & Monitoring
Infrastructure
Processed Data
Insights &
Information
Shared R&D + Innovation projects
Focus on extreme cold & hot temperature testing
Focus on extreme cold & hot temperature testing
Data from lab and field testing
Knowledge, insight and understanding
CAPEX OPEX Yield
100€/MWh (Target Dong Energy)
Drivers for wind energy R&D
100€/MWh (Target Dong Energy)
Drivers for wind energy R&D
𝑪𝒐𝑬 = 𝑪𝑨𝑷𝑬𝑿 + 𝑶𝑷𝑬𝑿
𝑨𝑬𝑷
Reliability
Reliability & Availability
Reliability means: ‘the ability of a system to perform a required function, under given environmental and operating conditions and for a stated period of time’ .
Downtime: lost revenue = 5.000-15.000 €/day
Teesside Offshore Wind Farm – January 2014
Teesside Offshore Wind Farm – January 2014
Teesside Offshore Wind Farm – January 2014
Teesside Offshore Wind Farm – January 2014
Teesside Offshore Wind Farm – January 2014
Transformers are key components in a wind farm
In the beginning: off the shelf distribution transformers failed Unusual duty cycle Environmental conditions
In the turbine: fire risks, leakage,
low frequency stress cast resin transformers, lightning, thermal stress,…
Technology matured by trail & error Offshore high voltage substation: Transformer failure: big financial impact No power production of wind farm (4,5 months - 1 year)
It takes time to reach a mature technology
It takes time to reach a mature technology
Brothers Wright – First flight 1903
Airbus – First flight - 2005
102 years of development
1991 First offshore wind farm (nearshore) 450 kW turbines 4.95MW farm
22 years of development
2013 One of the latest offshore wind farms 6.5 MW turbines 325MW farm
36 8 3 10
Technological evolution
Time-to-market = important
Technological evolution:
Optimization VS radical innovation
Nacelle installed transformer
Tower installed transformer
Platform installed transformer:
+36kV solutions – multi-MW
turbines
Reliability = Key
Maintainability = Key
How to increase resilience and
mitigate the Risk?
1) Design input based
on field experience and realistic requirements need for field data
Overview environmental loads on wind turbines
Overview environmental loads on wind turbines
Belgian North Sea: Standard Offshore turbines Operating spec. temperatures: -10°C …+40°C
Northern Baltic Sea: CCV offshore turbines Operating spec. temperatures: -30°C …+40°C
Pori Offshore 1 Wind Farm – Northern Baltic Sea Arctic conditions -35°C
Onshore cold climate turbine – Mongolia : -50°C during winter night
Offshore station – North Sea – extreme waves
Offshore station – North Sea – extreme waves
9
10
4
8
5
1
2
6
7
3 Vibration Signals
Fundamental vibration modes
24.06.14 36
Belwind Winf Farm – 45 km from shore – North Sea Installation Alstom 6MW Haliade prototype
Hot climate Wind Farm – temperature specification: +50°C Heat dissipation transformer, cooling drivetrain,…
Hot climate Wind Farm – temperature specification: +50°C Heat dissipation transformer, cooling drivetrain,…
Challenge: Wind turbines are installed word wide
Therefore, wind turbines are subjected to different environmental loads
Design classification with regard to different climatic sites
Corrosive environment
Humidity & Rain
Strong gusts & heavy wind loads
Wave impacts; low freq. vibrations
Vibrations due to wind loads
(Extreme) cold temperatures: -40°C; -45°C
Ice-rain & icing
Heavy wind loads
Snow
Vibrations due to wind loads
(Extreme) hot temperatures : +45°C; 50°C;
Sand & dust
Vibrations due to wind loads
Solar radiation
Offshore wind turbines CCV wind turbines HCV wind turbines
Which requirements?
1) Wintertime more good wind conditions
2) Fact by EON : wind turbines produce 11% more power at -10°C than at +20°C
Climatic class EN 60076-11:
C1, C2, C3*
Which requirements?
2014 – extreme temperature events
Canada (Saskatoon) January 2014: -49°C
Chicago January 2014: -30°C
North China February 2014: -46°C
Mongolia: -50°C
Sweden 16/01/2014: -30°C USA: Polar vortex
causes cancellations of turbine maintenance tasks - 2014
How to increase resilience and
mitigate the Risk?
2) Test and validate all components and the full system for all possible operating
conditions to find weak links
Also for extreme environmental conditions
Such conditions don’t occur often, but if they do they can have a big impact when not been taken into consideration
The Challenger disaster was caused by the failure of an "O-ring" seal in the solid-fuel rocket on the shuttle's right side. The seal's faulty design and the unusually cold weather, which affected the seal's functioning, allowed hot gases to leak through the joint”
Environmental testing of transformers:
Environmental testing of transformers
Climate chamber testing of transformers
Why such test?
Transformers used in wind farm are far more exposed to (extreme) cold and/or hot temperatures than ‘conventional power plants’ due to their geographic location and their location inside the turbine
Example extreme event = cold start-up: thermal stress mechanical stress
To mitigate risk: prototype test (over-stress test, fatigue test) to check for leakage, cracks, performance,…
Simulation VS testing field data needed, time-to-market plays a role
Requested by certification body or customer as proof of safe & reliable operations in all conditions
Climate chamber testing of transformers
Challenge?
Hi-tech infrastructure needed to cope with such tests
Multi-MW trend & Dimensions
External Lab VS in-house (freq. of such tests?)
Extreme temperatures / cooling power
Climate chamber testing of transformers
Focus cold climate – Liquid Filled transformers
Storage test at -40°C: check for leakages/cracks on seals, thin plated cooling fins, bushings, cables,…
Cold start-up test at -30°C:
Check leakage/ cracks due to brittle material in combination
with pressure increase (thermal & mechanical stress)
Check natural cooling performance of transformer liquid during cold start-up
Paper EWEA: Cold start of a 5.5MVA offshore transformer
Check leakage/ cracks due to brittle material in combination with pressure increase (thermal & mechanical stress):
Temperature influences the gas cushion (if used) and the liquid level of the transformer Internal pressure changes
The internal pressure and liquid level must stay within a certain range in order to guarantee optimal performance
Pressure peaks switch off transformer negative impact availability Pressure peaks brittle material exceptional mechanical stress
Worst case: interaction of the gas cushion/ liquid level can lead to negative impact on elasticity of the tank: unacceptable stress cracks & leakage risk
Mitigate this risk through simulation and testing
Climate chamber testing of transformers
Focus cold climate – Liquid Filled transformers
Climate chamber testing of transformers
Focus cold climate – Liquid Filled transformers
Check natural cooling performance of liquid during cold start-up:
A design verification test was needed to proof that there was sufficient internal cooling during cold start-up events as simulating such an event is difficult and complex.
Due to the higher viscosity at low temperature of the used cooling liquids, the natural convection cooling of the internal windings may be limited in such way that the initial losses generated inside the transformers windings cannot be evacuated fast enough RISK !
Approach -30°C Full load cold test on a 5,5MVA transformer
Approach -30°C Full load cold test on a 5,5MVA transformer
Approach -30°C Full load cold test on a 5,5MVA transformer
Climate chamber testing of transformers
Focus cold climate – Cast Resin Transformer
Check for cracks at low temperature operations:
Thermal stress mechanical stress due to brittle materials.
OWI-Lab has set-up a partnership with HV-Lab KEMA Arnhem
to cope with cast resin transformer tests at extreme low temperatures: -40°C, -50°C, -60°C
Example guideline thermal shock testing cast resin
Climate classes defined by IEC 60076-11 Class C1: the transformer is suitable for operation at ambient temperatures down to -5°C. (Exposed for storage & transportation: -25°C) Class C2: the transformer is suitable for operation at ambient temperatures down to -25°C (Exposed for storage & transportation: -25°C, -30°C or -40°C) Class C3*: the transformer is suitable for operation at -40°C, -50°C or -60°C
(storage & transportation: -40°C, -50°C or -60°C)
Climate chamber testing of transformers
Focus cold climate – Cast Resin Transformer
Power electronics
Variable wind patterns
Transformer windings
subjected to a rapid increase
of heat
In low temperature operations/
cold start-up sequence: brittle windings
(= additional risk)
Cracks partial discharge
in concentrated area which can
not be dissipated = RISK
CONCLUSION:
Reliability = key to wind energy (offshore)
Fast increasing technological evolution
Wind turbines are installed at extreme climatic sites
Field data is needed to optimize requirements
Advanced component and system testing is becoming important in the strategy to mitigate risks
Case studies with regard to transformers and climate chamber testing indicate the importance to do so
Thank you for your attention!
www.owi-lab.be/
www.sirris.be
@OWI_lab
Group: Offshore Wind Infrastructure
Application Lab (OWI-Lab)