ML19219A172
| ML19219A172 | |
| Person / Time | |
|---|---|
| Issue date: | 07/24/2019 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| K. Hamburger 415-2022 | |
| Shared Package | |
| ML19219A167 | List: |
| References | |
| Download: ML19219A172 (128) | |
Text
Public Meeting - July 24th, 2019 High Energy Arcing Faults (HEAF) Research Program Mark Thaggard, Deputy Director Office of Nuclear Regulatory Research Division of Risk Analysis July 24, 2019
Public Meeting - July 24th, 2019 Two meetings today:
- Morning
- Comment resolution
- HEAF Working group update
- Afternoon
- HEAF hazard modeling approaches
- Meeting material provided in advance of the meeting Agenda
Public Meeting - July 24th, 2019 High Energy Arcing Faults (HEAF) Research Program Mark Henry Salley P.E.
Office of Nuclear Regulatory Research Division of Risk Analysis July 24, 2019
Public Meeting - July 24th, 2019 May 11, 2017 NRC Full Commission Meeting
- Industry requests to work with NRC on HEAF issue Full-scale test plan public comment period (April 2017)
- 82 FR 36006 Small-scale test plan public comment period (March 2018)
- 83 FR 9344 Public workshop (April 2018)
- NUREG/CP-0311 ACRS briefing (August 2018)
Public meeting (January 2019)
Public Meeting (March 2019)
Todays Meeting (July 2019)
Numerous Public Interactions
Public Meeting - July 24th, 2019
- National Institute of Standards and Technology (NIST)
- Experts in Fire Measurements
- Sandia National Laboratories
- Experts in Fire Measurements, Electrical Measurements and Using Video as Data
- Extensive Department of Energy Research Experience
- KEMA High Power Laboratory
- DNV GL
- 90 years inspection, testing, and certification
- BSI Electrical Contractors
- Heavy Industrial Electrical Contracting HEAF Project Partners
Public Meeting - July 24th, 2019
- Comprised of EPRI and NRC technical experts
- Working under the Memorandum of Understanding
- Two, multi-day in person meetings in 2019:
- February 19-22
- June 10-12
- 21 working group webinar/phone meetings to date
- Excellent technical discussions
- Improves overall quality of HEAF program
- Currently working on expanding communications outside the working group to better share information HEAF Working Group
Public Meeting - July 24th, 2019 High Energy Arcing Faults (HEAF) Test Program Comment Resolution Nicholas Melly Kenneth Hamburger Gabriel Taylor P.E.
Mark Henry Salley P.E.
Office of Nuclear Regulatory Research Division of Risk Analysis July 24, 2019
Public Meeting - July 24th, 2019
- Update stakeholders on the disposition of outstanding comments
- Initial comment period
- April 2018 workshop
- January 2019 public meeting
- March 2019 public meeting
- Other stakeholder interactions Objective
Public Meeting - July 24th, 2019
- Is an 8-second test realistic?
- Operating Experience
- Operating experience has identified multiple cases where prolonged duration events have occurred in both US and International OE
- Medium Voltage prolonged duration events are consistent with generator-fed fault conditions and protection failure events
- Low Voltage prolonged duration is plausible at currents which potentially fall between circuit protection set points Stakeholder Comments Test Duration
Public Meeting - July 24th, 2019 Stakeholder Comments Test Duration (cont.)
- Working Group activities
- More realistic modeling
- Modeling will NOT be one size fits all as currently in NUREG/CR-6850 EPRI 1011989
- NRC/EPRI WG event tree/plant configuration and protection scheme taken into account
- Low Voltage tests will be performed at 8 seconds under the acknowledgement that the results will only be applicable to specific configurations
- The data from the low voltage tests will be investigated by the working group for the potential to inform medium voltage extended duration events beyond the test lab capability
Public Meeting - July 24th, 2019 Stakeholder Comments Fault Location Main bus bar arc wire (blue)
Breaker Stabs Arc Wire
Majority of the medium voltage switchgear events occurred in the supply switchgear configuration Majority of the faults occurred at the supply breaker stabs and main bus bars
Public Meeting - July 24th, 2019
- Working Group Discussion
- Supplementary test on the main bus bars in supply configuration to be conducted in 2020
- Data from Phase I testing on the breaker stabs is being compiled for use in evaluating the impact of faults on the breaker
- Potentially handled with split fraction in ZOI Stakeholder Comments Fault Location
Public Meeting - July 24th, 2019
All low voltage events occurred in the load center supply cubicle All faults initiated at the supply breaker stabs
- NRC has modified equipment from the initial test plan to include the supply cubicles Stakeholder Comments Load Center Design
Public Meeting - July 24th, 2019
- Stakeholders have requested two types of supplementary tests:
- Generator decay curve to more closely simulate generator-fed fault
- Supply configuration switchgear test
- NRC plans to conduct both supplementary tests in Spring 2020 Stakeholder Comments Supplementary Tests
Public Meeting - July 24th, 2019
- The use of modeling to extend the applicable range of test data is being considered by the Working Group.
- Afternoon meeting will address:
- Modeling approach
- Data needs, inputs, and outputs
- Validation and verification Stakeholder Comments Modeling
Public Meeting - July 24th, 2019 Working group has not completely resolved this issue Exploring several types of measurements (discussed in more detail in next presentation)
EPRI developed the specifications and design for a mock switchgear, and it was vetted by the working group The MSTU has not been validated to be representative of plant equipment No funding to build MSTU Stakeholder Comments Combustion Cloud Conductivity
Public Meeting - July 24th, 2019
- How is the impact of aluminum being isolated in testing to resolve PRE-GI-018?
- Direct comparisons in test matrix design
- Use of modeling
- Small-scale testing to identify properties of aluminum
- Verify scalability of small-scale results Stakeholder Comments Isolating the Impact AL
Public Meeting - July 24th, 2019
- Why remove the HRR calorimetry hood?
- Doesnt capture initial blast
- Ensuing fire HRR data available from phase I
- Immediate ignition of all cabinet internals observed
- Cost and logistics
- Construction, sensitive equipment, calibration, breakdown, placement, etc.
Stakeholder Comments HRR Calorimetry Hood
Public Meeting - July 24th, 2019
- External and public stakeholders have requested a way to be apprised of Working Group progress and project status
- The Working Group will be developing a website to improve communication in real time with details on all major project components Stakeholder/WG Interaction
Public Meeting - July 24, 2019 High Energy Arcing Faults (HEAF)
Working Group Status Update Nicholas Melly Nuclear Regulatory Commission Office of Nuclear Regulatory Research Marko Randelovic Electrical Power Research Institute Senior Technical Leader
Public Meeting - July 24, 2019
- Provide overview of NRC/EPRI working group (WG) activities and progress
- WG Mission
- PRA modeling approach / update
- Lessons learned from operational experience review
- Testing approach
- Project Plan Purpose 2
Public Meeting - July 24, 2019 NRC / EPRI Working Group (WG)
Charter Mission Statement
- To improve understanding of risk from electrical arcing fault hazards in nuclear power plants (NPPs).
Goals
- Better understand key factors contributing to:
- Occurrence
- Severity
- Advance HEAF fire PRA modeling
- Based on experimental data, operating experience, and engineering judgement
- Ignition frequency
- Zone of influence (ZOI)
- Analyze plant impact and risk implications Weekly Meetings
Public Meeting - July 24, 2019 Ken Fleischer (Fleischer Consultants)
Dane Lovelace (Jensen Hughes)
Shannon Lovvern (TVA)
Tom Short (EPRI)
Marko Randelovic (EPRI)
Ashley Lindeman (EPRI)
NRC / EPRI WG Team Project Managers Kelli Voelsing (EPRI)
Mark Henry Salley (NRC)
Project Sponsors Tina Taylor (EPRI)
Michael Cheok (NRC)
Dr. Chris LaFleur (SNL)
Nicholas Melly (NRC)
Kenn Miller (NRC)
Gabriel Taylor (NRC)
Public Meeting - July 24, 2019
- EPRI/NRC HEAF Methodology Report
- Extensive OpE review
- Fault Duration
- Fault Location
- HEAF Fire Ignition Frequency
- 1E vs. Non-1E investigation
- HEAF redefinition to fit OpE and modeling uses
- Risk Model Development
- Event Trees
- HEAF Non-Suppression Curve
- HEAF modeling guidance
- Data Analysis NRC/EPRI WG Activities
Public Meeting - July 24, 2019 Research and test durations are based on operating experience Millisecond fault occurrences are not part of the HEAF frequency bins OpE Review identified additional generator fed faults than previously known NRC/EPRI WG Activities Operating History (OpE review)
Plant Event Event classification Event Duration Palo Verde (M Voltage) 7/6/1988 Arc Blast 0.75 sec (actual duration)
DC Cook (M Voltage) 7/13/1990 HEAF Likely 0.5 sec Waterford (M Voltage) 6/10/1995 HEAF 4-8 sec (estimated:
generator fed)
SONGS (M Voltage) 2/3/2001 HEAF 4-8 sec (estimated:
generator fed)
Prairie Island (M Voltage) 8/3/2001 HEAF 4-8 sec (estimated:
generator fed)
Robinson (M Voltage) 3/28/2010 HEAF 1st Event: 20 sec (actual HEAF duration)
Robinson (M Voltage) 3/28/2010 HEAF 2nd Event: 3 Min high impedance fault followed by unknown duration HEAF event Palo Verde(M Voltage) 7/3/2013 HEAF Estimated < 2 seconds (however, photo evidence that protection may have operated much faster)
Brunswick (M Voltage) 2/7/2016 Arc Blast 0.15 sec (estimated duration)
Yankee Rowe (L Voltage) 8/2/1984 HEAF Unknown Fort Calhoun (L Voltage) 6/7/2011 HEAF 42 sec (actual duration)
River Bend (L Voltage) 2/12/2011 HEAF 12 Sec
Public Meeting - July 24, 2019 Fault Characteristics Fault Duration 0
2 4
6 8
10 12 Unknown 0.5 1
2 4
12 20 50 Number of Events Duration of Fault (seconds)
Actual Duration Estimated Duration Investigation of OpE event duration to ensure testing and modeling efforts representative
Public Meeting - July 24, 2019
- Low voltage cabinets were procured using input and recommendations from the WG
- Testing parameters will be adjusted accordingly to mimic faults from OpE
- Current WG activity to investigate typical protective device setpoints Evaluation of the US OE Low Voltage Plant Event Event classification Event Duration Germany (L Voltage) 5/30/1986 HEAF 8.5 Sec Yankee Rowe (L Voltage) 8/2/1984 HEAF Unknown Fort Calhoun (L Voltage) 6/7/2011 HEAF 42 sec (actual duration)
River Bend (L Voltage) 2/12/2011 HEAF 12 Sec Ref. Westinghouse I.B. 33-790-1E
Public Meeting - July 24, 2019 NRC/EPRI WG Activities Testing-Supply vs. Load Fall 2018 testing followed IEEE guidance with respect to arc wire location and size Working group review of OE on medium voltage switchgear revealed majority of the medium voltage switchgear events occurred in the supply switchgear configuration and involved main bus work
- Configuration and equipment type has been identified as parameters of interest
- Working group is currently discussing options to most accurately reflect realism in a testing environment
Public Meeting - July 24, 2019
- Event Frequency classification
- Need for clear definitions
- Subdivide Bin 16 (NUREG/CR-6850)
- Arc Fault Class 1 (Arc Flash)
- Arc Fault Class 2 (Arc Blast)
- Arc Fault Class 3 (HEAF)
- NRC working with NFPA/IEEE & EPRI Working Group
- Continued discussion to finalize definitions for arc fault events
- Updated frequencies for HEAF events to be developed by the NRC/EPRI HEAF WG to coincide with the ZOI methodology and event tree modeling approach NRC/EPRI WG Activities Frequency Review
Public Meeting - July 24, 2019 Arc Fault Classifications 11
Public Meeting - July 24, 2019
- Approach being developed by the WG to incorporate plant design with ZOI and HEAF susceptibility
- More accurate reflection of realism
- Major improvement over a one size fits all model
- Currently in the developmental stage with WG NRC/EPRI WG Activities PRA Risk Model Development
Public Meeting - July 24, 2019 NRC/EPRI WG Activities Risk Model Development Generic Frequency x
Ignition Source Weighting Factor Location SWGR Breaker Available Source Design Generator Circuit Breaker Duration ZOI End Sequence (Zone 2)
End Sequence (Zone 1 & 5)
< 2 ZOI 1 A2 N/A (Zone 2)
GCB Works
< 4 ZOI 2 B2 A1 Supply GCB Fails 4 - 8 ZOI 3 C2 B1 4 - 8 ZOI 3 D2 C1 (Zone 1)
< 4 ZOI 2 E2 A5 g*Wis
< 2 ZOI 1 F2 N/A (Zone 2)
GCB Works
< 4 ZOI 2 G2 N/A Load GCB Fails 4 - 8 ZOI 3 H2 N/A 4 - 8 ZOI 3 I2 N/A (Zone 1)
< 4 ZOI 2 J2 N/A SWGR Breaker Unavailable/Fails Unit Auxiliary Transformer Site Auxiliary Transformer Unit Auxiliary Transformer Site Auxiliary Transformer Generator Circuit Breaker No Generator Circuit Breaker No Generator Circuit Breaker Generator Circuit Breaker SWGR Breaker Available AND Functions SWGR Breaker Available AND Functions SWGR Breaker Unavailable/Fails
Public Meeting - July 24, 2019 Temperature and Heat Flux
- Both parameters will be modeled at multiple distances away from the arc location
- Will aid in a dynamic ZOI creation
- Link to SNL Fragility criteria testing (to be discussed in the afternoon)
Pressure (improved measurement techniques developed)
- Potential to measure impact on room pressure currently being explored Damage Zone Furthest extent of damage
- Thermal (i.e. ensuing fire damage / smoke damage)
- Physical ( i.e. thrown cabinet door, shrapnel)
Conductivity
- SNL Measurements
- Other Options HEAF Phase II Testing Measurement
Public Meeting - July 24, 2019 Mass of Material Vaporized Measurements pre-and post-testing to validate computer models and theory equations of vaporized material Potential to develop approximate energy release models from classical energy conversion models Cable Sample Material Cable samples placed at varying distances away from enclosure Byproduct Testing Samples Carbon Tape & Aerogel used in 2018 Carbon Tape & Silicon/Quartz in 2019 Conductivity measurements for aluminum deposited on surfaces Spectroscopy Heat Release Rate (HRR) measurement is impratical based on lessons learned in phase I testing HEAF Phase II Testing Measurement (continued)
Public Meeting - July 24, 2019
- SNL has experience with this type of measurement
- Surface conductivity
- Passive measurements
- Interdigitated resistivity measurement structures
- Parallel conductive traces
- Evaluate voltage holdoff/surface flashover properties
- Concentric ring surface resistance measurement (ASTM D257)
- This instrumentation will address the potential for failure of electronic equipment exposed to the arc ejecta or smoke generated by the HEAF event HEAF Phase II Testing Surface Conductivity Measurements
Public Meeting - July 24, 2019
- Conductivity sensor
- Active measurement
- Mesh design for EMI rejection
- Air conductance measured as voltage in circuit HEAF Phase II Testing Air Conductivity Measurements
Public Meeting - July 24, 2019 Purpose of the Mock Switchgear Test Unit (MSTU) is to verify if liberal amounts of aluminum combustion cloud byproduct/debris is sufficient to cause collateral damage (flashover) in nearby/adjacent medium voltage.
To the extent practical, the MSTU is to represent typical switchgear with respect to voltage, bus bar spacing and standoff insulators to ground MSTUs are portable, re-usable and do not require excessive power Provides prototypical configuration to evaluate flashover Mock Switchgear Test Unit Evaluate flashover (arc-over)
Public Meeting - July 24, 2019
- Design of the MSTU is based on a bounding approach to which type electrical distribution system (EDS) is most vulnerable to a flashover or tracking phenomenon out of:
- Wye system (solidly grounded)
- Wye system (resistance grounded)
- Wye (ungrounded neutral)
- Delta (ungrounded)
- Uninsulated bus bars Mock Switchgear Test Unit Evaluate flashover (arc-over)
Public Meeting - July 24, 2019 HEAF Phase II Testing Conductivity-Benefits and Limitations Type Benefit Limitation Surface Conductivity Known Measurement Technique Can measures hold off
/ break down in addition to surface resistance Passive design Does not measure air conductivity Requires failure criteria of components which may require additional testing or engineering judgment Air Conductivity Active instrumentation Limited number to deploy Mock Switchgear Close simulation of plant equipment Bounding result (Exclusionary)
Public Meeting - July 24, 2019 Aug/Sept 19 Phase II Tests Electrical Enclosures Legend OECD/NEA HEAF Phase 2 Tests U.S. NRC specific supplemental testing driven by generic issue aluminum HEAF program Uncommitted tests to explore unanticipated results/enhance repetition if necessary Enclosure Testing Aluminum Bus Bars Copper Bus Bars 6900 Volt 480 Volt 6900 Volt 25kA 15kA 35kA 25kA 4s 2-2 35 kA 480 Volt 25 kA 15kA 25kA 4s 2-5 4s 2-8 4s 2-9 4s 2-11 4s 2-12 4s 2-14 4s 2-17 4s 2-20 2s 2-22 4s 2-23 2s 2-1 2s 2-4 2s 2-7 2s 2-10 4s 2-24 X
X 8s 2-6 8s 2-3 2s 2-13 8s 2-15 2s 2-16 8s 2-18 4s 2-21 2s 2-19
Public Meeting - July 24, 2019 Legend OECD/NEA HEAF Phase 2 Tests U.S. NRC specific supplemental testing driven by generic issue aluminum HEAF program Uncommitted tests to explore unanticipated results/enhance repetition if necessary Aluminum Bus Steel Enclosure Copper Bus Aluminum Enclosure Aluminum Bus Aluminum Enclosure Copper Bus Steel Enclosure 4s 2-26 2s 2-25 2s 2-27 4s 2-28 4s 2-30 4s 2-32 2s 2-31 Bus Duct Testing 4160 Volt /
25 kA 2s 2-29 5s 2-33 5s 2-34 Phase II Tests Bus Ducts Aug/Sept 19
Public Meeting - July 24, 2019
- New information used as identified to re-evaluate objectives of test plan
- Changes being proposed to focus on
- Configuration
- Arc location
- Equipment design
- Decrement
- Arc Current
- Duration Phase II Test plan re-evaluation
Public Meeting - July 24, 2019 Phase II Tests Electrical Enclosures-Spring 2020 Enclosure Testing MV Supply Side Config.
Aluminum Horizontal Draw-out Breakers 2x-4 4s Vertical Lift Breakers 2x-3 4 s 2x-2 Decrement Curve*
Copper Vertical Lift Breakers 2x-1 Decrement Curve*
Focus of decrement curve testing is to be representative of NPP OpE and generator characteristics to determine appropriate testing conditions Decrement tests 2x-1 2x-2 Confirmatory tests 2x-3 2x-4 Working Group recommendations for both equipment procurement, test design conditions and applicability to plant realism has been incorporated into the upcoming Summer 2019 and Spring 2020 and test series and will continue to be actively incorporated into future testing
Public Meeting - July 24, 2019
- Project plan is being developed to capture all components of the HEAF research program and how they fit together
- History
- Scoping/Literature Studies
- Phase I Testing
- Small Scale Testing
- Phase II Testing
- Modeling and Analytical Work
- NRC webpage will be hosted for easy reference and tracking
- This will be in addition to the Generic Issues Dashboard site Project Plan
Public Meeting - July 24, 2019 High Energy Arcing Faults (HEAF)
Hazard Modeling Gabriel Taylor P.E.
Office of Nuclear Regulatory Research Division of Risk Analysis July 24, 2019
Public Meeting - July 24, 2019
- Provide overview of modeling
- History
- Types
- Measurements supporting hazard modeling
- Existing models
- Comparisons to measurement
- Air Breakdown Purpose
Public Meeting - July 24, 2019 Categories of Electrical Enclosure Failure Mode - Review
Public Meeting - July 24, 2019 Highlighted HEAF hazard NRC INFORMATION NOTICE 2002-27 RECENT FIRES AT COMMERCIAL NUCLEAR POWER PLANTS IN THE UNITED STATES https://www.nrc.gov/docs/ML0226/ML022630147.pdf Operating Experience San Onofre Nuclear Generating Station, 2001
Public Meeting - July 24, 2019 NUREG/CR 6850 forms the basis for nuclear power plant (NPP) Fire PRAs
- Published 2005 This EPRI/NRC working group was the first to explicitly model HEAF events as part of a fire PRA
- The need was identified as part of accident investigation efforts for the development of 6850 & NRCs assessment of energetic faults from 1986-2001
- (ADAMS Accession No. ML021290364)
- Timely OpE-San Onofre 2/3/2001 Fire PRA Methodology NUREG/CR-6850 EPRI 1011989 https://www.nrc.gov/readin g-rm/doc-collections/nuregs/contract
/cr6850/
Public Meeting - July 24, 2019 NUREG/CR-6850, Appendix M (2005)
Zone of Influence (ZOI) Method largely based on one well documented fire event at San Onofre in 2001 Methodology developed as an expert elicitation
- Observational data and OpE information only
- No test data available
- Currently this model has been used to support NFPA 805 transitions Current Methodology Electrical Enclosures 6
Public Meeting - July 24, 2019 HEAF OpE Electrical Enclosure SONGS, 2001 San Onofre; 2001 Onagawa; 2011
Public Meeting - July 24, 2019 Current Methodology Bus Ducts NUREG/CR-6850, Supplement 1 Bus duct guidance for high energy arcing faults (FAQ 07-0035)
Methodology developed as an expert elicitation
- Observational data and OpE information only
- No test data available
- Currently this model has been used to support NFPA 805 transitions
Public Meeting - July 24, 2019 HEAF OpE Bus Duct Columbia Bus Duct (OpE) 2009 Diablo Canyon Bus Duct (OpE) 2000 Bus Duct Testing 2016
Public Meeting - July 24, 2019 Conceptual Modeling Approaches
Public Meeting - July 24, 2019
- Bounding (Current models)
- Enclosure, bus ducts
- Bounding by Categories
- By power, energy, voltage, fault current, protection scheme, material, safety class
- Dynamic ZOI
- Scenario dependent source
- Target fragility Modeling Approach 11 As presented at 4/18/2018 public workshop
Public Meeting - July 24, 2019
- Assumes worst case damage for all HEAF
- i.e., one size fits all
- Damage and ignition of components within ZOI
- Peak HRR
- Least amount of information needed to determine ZOI
- Least realistic for majority of cases
- Simple to apply
- Lowest cost Bounding ZOI (Current Model) 12 As presented at 4/18/2018 public workshop
Public Meeting - July 24, 2019
- Subdivides equipment by HEAF damaged potential
- Equipment type
- Energy/Power potential
- Protection scheme
- Size, Material, Design, etc.
- More realistic
- Requires more information to apply
- More costly for development and application Refined Bounding ZOI 13 As presented at 4/18/2018 public workshop
Public Meeting - July 24, 2019
- Requires detailed information on power system
- Correlation from experiments and theory to model source term and incident flux as a function of distance
- Requires knowledge of fire PRA target fragility to high heat flux short duration.
- Potential to provide most realistic results
- Complex to apply
- Most costly Dynamic ZOI 14 As presented at 4/18/2018 public workshop
Public Meeting - July 24, 2019
- No approach has been excluded
- Understand and evaluation existing and new hazard models
- Needs to consider development and application efficiencies along with level of realism in a holistically manner to make informed decision on approach
- NRC/EPRI working group advancing PRA modeling methodology Modeling Approach Status
Public Meeting - July 24, 2019 Measurements to evaluate existing models
Public Meeting - July 24, 2019 Instrument Stands ASTM Slug Calorimeter Tungsten Slug Calorimeter Plate Thermometer Black Carbon Tape AERO Gel PVC peak temperature
Public Meeting - July 24, 2019
- Electrical
- Voltage, current, energy
- Pressure
- Physical dimensions
- Bus gap
- Distance to instruments Measurements
Public Meeting - July 24, 2019 Overview of Existing Models
Public Meeting - July 24, 2019
- Simple geometric configuration
- arc modeled as sphere
- Heat transfer to predict distance where threshold is exceeded
- Used available research on human skin / clothing fragility (Stoll / Artz)
- Conservative due to maximum arc power assumption
- Used in IEEE 1584-2002 for > 15kV applications Theoretical Lee Model R. Lee, The Other Electrical Hazard: Electric Arc Blast Burns, 1982
Public Meeting - July 24, 2019
- Output
- IE, incident energy (J/cm2)
- Inputs
- V, system voltage (kV)
- t, arcing time (seconds)
- Ibf, 3 phase bolted fault current
- D, distance from arc point Theoretical Lees Method ASTM slug T-cap. slug KEMA Daq Physical Measurement R. Lee, The Other Electrical Hazard: Electric Arc Blast Burns, 1982
Public Meeting - July 24, 2019 Semi-Empirical Wilkins-Allison-Lang Method Output IE, incident energy Input VLL, line-line voltage V, system voltage Varc, arc voltage Iarc, arc current t, arcing time D, distance from arc point a, enclosure dimension g, gap Ve, electrode voltage ASTM slug T-cap. slug KEMA Daq Physical Measurement Literature R. Wilkins, M. Allison, M. Lang, Improved Method for Arc Flash Hazard Analysis, 2004
Public Meeting - July 24, 2019 Semi-empirical Gammon Simplified T. Gammon, J. Matthews, The IEEE 1584-2002 Arc Modeling Debate and Simple Incident Energy Equations for Low-Voltage Systems, 2006 Output IE, incident energy Input MVAsc, short-circuit MVA t, arcing time D, distance from arc point X, configuration factor (IEEE)
IEratioUB, Incident energy rate ratio upper bound (configuration based 0.758 - 2.098)
ASTM slug T-cap. slug KEMA Daq Physical Measurement Literature
Public Meeting - July 24, 2019
- Output
- EMA,EMB, Max. Incident Energy
- Input
- F, 3-phase short-circuit current
- tA, tB, arc duration
- DA,DB, distance Empirical - Statistical Doughty - Neal - Floyd ASTM slug T-cap. slug KEMA Daq Physical Measurement R. Doughty, T. Neal, H Floyd, Predicting Incident Energy to Better Manage the Electric Arc Hazard on 600-V Power Distribution System, 2000
Public Meeting - July 24, 2019
- Guide for performing arc flash calculations
- Model for incident energy calculations
- Empirically derived model from 300 tests
- Methodology focused on personal protection
- Arc flash boundary is only applicable to human fragility
- Arc fault current and incident energy are independent of target Empirical - Statistical IEEE 1584 - 2002 IEEE 1584-2002, Guide for Performing Arc-Flash Hazard Calculation, 2002
Public Meeting - July 24, 2019 Empirical - Statistical IEEE 1584 - 2002
- Output
- IE, Incident Energy
- Input
- V, system voltage
- Ia, arc current
- t, arc duration
- G, conductor gap
- D, distance
- x, distance exponent
- Configuration (open / box)
ASTM slug T-cap. slug KEMA Daq Physical Measurement Literature IEEE 1584-2002, Guide for Performing Arc-Flash Hazard Calculation, 2002
Public Meeting - July 24, 2019
- Guide for performing arc flash calculations
- Significantly changed from 2002 edition
- Model for incident energy calculations
- Empirically derived model from 2,160 tests
- Five configurations
- VCB, VCBB, HCB, VOA, HOA Empirical - Statistical IEEE 1584 - 2018 IEEE 1584-2018, Guide for Performing Arc-Flash Hazard Calculation, 2018
Public Meeting - July 24, 2019
- System voltage: 208 to 15,000 Volts
- Frequency: 50 or 60 Hz
- Bolted fault current:
- Low Voltage: 500 to 106,000 A
- Med Voltage: 200 to 65,000 A
- Conductor Gaps:
- Low Voltage: 0.25 to 3 inches
- Med Voltage: 0.75 to 10 inches
- Target Distances: 12 inches
- Fault clearing time: no limit IEEE 1584 - 2018 Range of model
Public Meeting - July 24, 2019 Output
- IE, Incident Energy Input
- Iarc, Arcing current
- Voc, System voltage
- T, Duration
- D, Distance
- G, Conductor gap
- Enclosure Dimensions
- Equip Configuration Empirical - Statistical IEEE 1584-2018 ASTM slug T-cap. slug KEMA Daq Physical Measurement Literature
Public Meeting - July 24, 2019
- Model overpredict max measured incident energy
- Maximum overprediction : ~11x
- 550 kJ/m2 measured vs. 6,100 kJ/m2 calculated
- Minimum overprediction : ~2x
- 3.4MJ/m2 measured vs. 6.3MJ/m2
- Note: 2 instruments damaged due to HEAF damage likely higher heat flux at damaged sensors and better agreement with model Model Comparison IEEE 1584 - 2018 vs MV Alum
Public Meeting - July 24, 2019
- Model overpredict max measured incident energy
- Maximum overprediction : ~17x
- 550 kJ/m2 measured vs. 9,100 kJ/m2 calculated
- Minimum overprediction : ~3x
- 3.4MJ/m2 measured vs. 9.4MJ/m2 calculated
- Note: 2 instruments damaged due to HEAF damage likely higher heat flux at damaged sensors and better agreement with model Model Comparison LEE vs MV Alum
Public Meeting - July 24, 2019
- T-cap slug calorimeter (tungsten)
- Model overpredict max measured incident energy
- Maximum overprediction : ~26x
- 236 kJ/m2 measured vs. 6,100 kJ/m2 calculated
- Minimum overprediction : agreement
- 6.0MJ/m2 measured vs. 6.3MJ/m2 Model Comparison IEEE 1584 - 2018 vs MV Alum
Public Meeting - July 24, 2019
- T-cap slug calorimeter (tungsten)
- Model overpredict max measured incident energy
- Maximum overprediction : ~39x
- 236 kJ/m2 measured vs. 9,100 kJ/m2 calculated
- Minimum overprediction : ~1.6x
- 6.0MJ/m2 measured vs. 9.4MJ/m2 Model Comparison LEE vs MV Alum
Public Meeting - July 24, 2019
- Follow similar form
- Inverse power relationship with distance to target
- Supporting test configurations not directly applicable
- Open air or box w/opening
- Fragility different (human vs equipment)
- Existing models may be adapted to make representative and realistic.
Wrap-up Existing Models
Public Meeting - July 24, 2019
- PHASE 1 testing has show functional failure of power bus due to HEAF effluent.
- Need to evaluate effects of HEAF effluent on secondary equipment due to surface (see working group slides) versus air electrical flash over
- Scientific approach to measuring voltage hold.
Air Holdoff Voltage Evaluation of arc over
Public Meeting - July 24, 2019
- Air breakdown strength changes with
- Gas density /
Temperature
- Metal vapor concentration
- AL ionized more easily than Cu Air Holdoff Voltage Modeling breakdown strenght G.J.M. Hagelaar and L.C. Pitchford, "Solving the Boltzmann equation to obtain electron transport coefficients and rate coefficients for fluid models",
Plasma Sci Sources and Tech 14, 722 (2005).
Public Meeting - July 24, 2019
- Based on ASTM D2477 Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Insulated Gases at Commercial Power Frequencies.
- Modified to
- Support short time duration of HEAF test
- Make many measurements per test
- UV illumination to ensure consistent results to standard stepped voltage approach.
- Allow for determination of voltage holdoff strength and confirmation of model.
Air Holdoff Voltage Approach
Public Meeting - July 24, 2019 Air Holdoff Voltage Device Geometry Node geometry: sphere/sphere Spacing between nodes: 1 cm Maximum voltage: 24 kV Ramp rate: 10 kV/µs Number of units employed: 2 Measure: V(t), I(t), T(t)
Particulate measurements via particle capture and spectroscopy
Public Meeting - July 24, 2019 Measure
- Temperature
- Particle concentration
- Current
- Voltage 39 Vmon CVT Temperature monitor Tmon fiber links Air Holdoff Voltage Test Arrangement
P R E S E N T E D B Y Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energys National Nuclear Security Administration under contract DE-NA0003525.
HEAF Modeling Modeling Approach and Analysis M a t t H o p k i n s, P h. D., Pa u l C l e m, P h. D., D a n i e l Ko t ov s k y, P h. D. & Ke n A r m i j o, P h. D., C h r i s L a F l e u r, P h. D.
E l e c t r i c a l S c i e n c e & E x p e r i m e n t s, C o n c. S o l a r Te ch n o l o g i e s, a n d R i s k & Re l i a b i l i t y D e p a r t m e n t s Ju l ; y 2 4, 2 0 1 9
HEAF Modeling Approach Outline 2
- Background on physics modeling drivers
- Arc modeling plan
- Arc modeling approach
- Lowke model
- Small scale experiments
- Particle characterization
- Multiphysics Arc Modeling Extension
- Progress update
- Next steps
- Target fragility and failure criteria
- Sandia National Labs models
HEAF Modeling Needs 3
December 2017 EPRI Product Id: 3002011922 https://www.epri.com/#/pages/product/000000003002011922/?lang=en-US
Goal: Provide improved predictive capability of HEAF incident energy leveraging Sandia air plasma models 4
Photovoltaics Bakersfield CA, April 5 2009 the ground-fault protection device was unable to interrupt the current, allowing arc faults to be formed, spreading sparks to surrounding materials, causing ignition.
-- Commercial Roof-Mounted Photovoltaic System Installation Best Practice Review and All Hazard Assessment, The Fire Protection Research Foundation, Feb. 2014 Nuclear Energy San Onofre Nuclear Generating Station, Feb. 3 2001 There was a failure of the main contacts of a 25 year old 4.16 kV breaker to close fully, causing a HEAF event the fire persisted for three hours until water was applied.
-- Brown et al., SAND2008-4820, High energy arcing fault fires in switchgear equipment, a literature review
Provide Improved Prediction of HEAF Incident Energy Aim: arc physical model, where DC current and electrode gap radiation, convective and thermal energy transport Accurate arc models needed to avoid overprediction of damage EPRI Product Id: 3002014641 https://www.epri.com/#/pages/product/000000003002014641/?lang=en-US
Opportunities in AC Arc Modeling Tools for the Simulation of the Effects of the Internal Arc in Transmission and Distribution Switchgear Working Group A3.24, December 2014 Aim: arc physical model, where AC current and electrode gap radiation, convective and thermal energy transport
Arc Modeling Plan Overview Model Arc
- Aria
- High Current Arc and Plasma Evolution
- Outputs to Fuego Model Sooty Flame/Jet
- Fuego
- Resulting Large Scale Heat Transport Enclosure/Barrier Flux and Temp Evolution
- Outputs from Aria/Fuego
- Predict Breach Evaluate Fragility
- Time Basis of Exposure
- Determine Critical Flux/Temps
- Link to Thief (?)
Model Range of Input Parameters
- I, Cu/Al, Gap, Type of Equipment
- Predict Distance to Critical Flux/Temps
- Create Matrix of ZOIs Vision: Non-conservative estimate of credible energy release scenarios and respective zones of influence for range of appropriate equipment at NPP Goal to develop model and resulting look-up table for:
- Arc plasma emission as a function of current and gap
- Incident energy as a function of current, breach geometry, and electrode material Measurements for validation
- Incident energy (slug/plate calorimeters)
- Thermal field (calorimeters, calibrated IR cameras)
- Radiated power (black ASTM calorimeters)
- Fragility samples (cables, secondary equipment enclosures, others as needed)
- Particle characterization (oxidation and morphology)
Modeling Plan
- Accurate validated predictive modeling is an iterative process
- Basic physics of the arc must be characterized first in Aria. Start with simple model of arc only and determine governing equations, make predictions, and compare to experimental measurements.
- Arc temperature, radius, radiative and heat transfer characteristics of emitted energy, and mass loss rate of conductors will be first parameters modeled
- Complexity will be added in layers
- Effects of magnetic forces, buoyancy, and orientation of conductors
- Each output parameter of the model will tie directly into the failure characterization of target equipment and will be measured and compared to small and large scale experimental data
- Model is not intended to be used by licensees, it is tool to aid joint NRC/EPRI Working group to make decisions on realistic ZOIs for a wider range of HEAF scenarios
Output of the Modeling Effort
- Output will be spatial characterization of emitted energy that, when combined with failure criteria for key targets, can be used by HEAF working Group to determine zones of influence
- Modeling will provide a tool for characterizing the HEAF hazard from a variety of scenarios
- Physics model will provide more realistic predictive capability and reduce need for costly experiments
- Parameters that are critical for determining if failure criteria for targets are being measured in full-scale experiments
- Model validation and quantification of total Joule heating (I2Rarct) is measured by:
Arc voltage, current, and resistence Radiated power (ASTM black Cu calorimeters), Electrode temperature (calibrated IR cameras)
Arc temperature (UV-visible-NIR spectroscopy)
Arc dynamics (high speed cameras)
10 Physical arc-fault energy models may be developed using prior literature and knowledge of:
Electrode gap Electrode metal (Cu, Al, )
Input current (100 A to 100 kA)
Conductivity of ambient (air, air + Al, air + Cu)
Thermal properties of ambient gas Arc Modeling Approach KEMA HEAF test switchgear Al bus bars, 11.5 cm gap
11 Physical arc-fault energy models may be developed using prior literature and knowledge of:
Electrode gap Electrode metal (Cu, Al, )
Input current (100 A to 100 kA)
Conductivity of ambient (air, air + Al, air + Cu)
Thermal properties of ambient gas Arc Modeling Approach KEMA HEAF test switchgear Al bus bars, 11.5 cm gap Radiation of long and high power arcs Y. Cressault et al. J. Phys. D: Appl. Phys. 48 415201 (2015)
Prediction of arc voltage, radius, temperature and power Basis: JJ Lowke Simple theory of free-burning arcs, J. Phys D 12, (1979) 12 Physical arc-fault energy models:
Electrode gap Electrode metal (Cu, Al, )
Input current (100 A to 100 kA)
Conductivity of ambient (air, air + Al, air + Cu)
Thermal properties of ambient gas Arc Modeling Approach KEMA HEAF test switchgear Al bus bars, 11.5 cm gap
Lowke Model: Isothermal Arc Model 13 Assumptions:
- Arc is in equilibrium and isothermal vs. radius
- Electrode thermal effects are neglected
- Air conductivity, air+Al conductivity calculated Total energy output (source term):
radiation + convection + conduction
Reference:
JJ Lowke Simple theory of free-burning arcs, J. Phys D 12, (1979) https://iopscience.iop.org/article/10.1088/0022-3727/12/11/016/meta
Lowke Model: Isothermal Arc Model Predictions 14 Predictions:
- HEAF arc energy is dominated by radiation at > 1 kA
- Presence of electrode vapor (Al or Cu) increases radiation
Small Scale Experiments for Modeling Validation Experimental testbeds have been developed for two capabilities:
1.
A capacitive discharge system for which a charge voltage of 1.5-11 kV, produces a stored energy 1-50 kJ, to support short duration arcs (100 ms) at high current (1 kA - 160 kA).
2.
A long-duration (1-120 s), arc-triggering constant current source, which uses a 100 A - 1 kA constant current supply Reproducible 30 s arc tests with Al, Cu, Fe & C electrodes have been performed at constant current Current source with line filter and transient voltage suppression Test gap with voltage and current diagnostics Impulse generator with reverse current protection Constant Current Source Arc-Generator Circuit Diagram 15 Measurements include:
Arc voltage, arc current, radiated power, thermal power Arc temperature (spectroscopy), IR cameras (calibrated to 3000K)
Lowke Model: Initial DC Experiments (5 second arcs) 16
Lowke Model: Initial DC Experiments (5 second arcs) 17
Lowke Model: Initial DC Experiments 18 Capability established for DC arc measurements at 50A to 500A to compare to arc models.
Radiation power measured agrees to model within 10-30%
Evaluating vertical, horizontal & parallel arc between Al and Cu electrodes during summer 2019 What we measure for model validation and quantification of total Joule heating (I2Rarct) :
Varc, Iarc ( Rarc(t) )
Radiated power (ASTM black Cu calorimeters), Electrode temperature (calibrated IR cameras)
Arc temperature (UV-visible-NIR spectroscopy)
Arc dynamics (high speed cameras)
Sandia testing July-Aug 2019 KEMA testing Aug-Sep 2019
Prior Small Scale Bus Bar Experiments 19 Variable voltage: 480 V, 4160V, 6900V, 10 kV, 100 ms arcs applied to copper vs. aluminum bus bars Bus bars were scaled to similar current density to KEMA HEAF testing Predicted V2/R scaling of mass loss vs. HEAF voltage: note Al & Cu data overlap.
Measured V2/R scaling of mass loss vs. HEAF voltage.
Prior Small Scale Bus Bar Experiments 20 Variable voltage: 480 V, 4160V, 6900V, 13.8 kV, 100 ms arcs applied to copper vs. aluminum bus bars Bus bars were scaled to similar current density to KEMA HEAF testing Predicted V2/R scaling of volume loss vs. HEAF voltage: note Al & Cu data overlap.
Measured V2/R scaling of volume loss vs. HEAF voltage.
Prior Small Scale Bus Bar Experiments 21 Evolved metal particle collection and analysis Key questions:
- 2) correlate aluminum particle oxidation with distance from switchgear
- 3) identify other potential sources of non-electrical incident energy and net energy contribution (heat of oxidation - aluminum, steel and other sources)
Particle Collection from 6.9 kV Arc Experiments 22 6.9 kV arc-generated Al particles (2.5-14 µm) were collected on aerogel substrates and carbon microscopy tape Surfaces of carbon tape and Al particles are coated with nanoparticle (5-30 nm) aluminum oxide particles
Particle Oxidation Analysis from 6.9 kV Arc Experiments 23 Degree of oxidation is quantifiable by energy dispersive x-ray analysis (EDS): surface skin vs. full oxidation Modeling goal: predict quantity of evolved metal and balance of radiated/thermal/oxidative energy evolved 73%
100%
micron-scale nano-scale
24 In Aria, a volumetric heat source was pre-defined based upon the modeling results of Lowke [1979] for convectively stabilized arcs, representative of the steady-state heating for arc stabilized predominantly by thermal conduction (see Lowke 1979, Fig. 9).
Calculations were performed over one-dimension with cylindrical symmetry, representative of arc regions free from the influence of electrode effects. The simulation domain ran from radii of 0 mm to 10 mm, with the outer boundary set to a condition of constant temperature at 273 K (i.e., a thermal wall).
The resulting temperature profile was checked to ensure a degree of consistency with the pre-defined volumetric heat source. Qualitative agreement with temperature profiles of wall-stabilized arcs (e.g.:
Lowke 1979, Fig. 2; Edels 1961, Fig. 10; Kimblin and Lowke 1973, Fig. 4) indicates that the Aria model is on-track and producing physically realistic results. Simple geometries are being modeled June-August 2019.
Multiphysics Arc Modeling Extension
ARIA: Governing Equations for Arc Modeling 25
- Conservation of mass:
- Conservation of momentum:
- Conservation of energy:
Advection Hydrostatic pressure Viscous pressure Buoyancy Magnetic pressure Advection Diffusion Joule heating Convection
Progress: Quasi-Transient Arc-Temperature Evolution 1-D Radial Analysis 26 Results of air simulation -- 1D slab, cylindrically symmetric, 10 mm boundary set to 273 K, Gaussian input heat profile at 600 W cm-3 with "1/e" radius of 4 mm
Edels, 1961 Kimblin &
Lowke, 1973 Aria Arc Temperature Model Results Arc Modeling Progress 27
10A Arc Aria Temperature Model Results Lowke, 1979 Lowke, 1979 Results of air simulation -- 1D slab, cylindrically symmetric, 10 mm boundary set to 273 K, Gaussian input heat profile at 600 W cm-3 with "1/e" radius of 4 mm 28 Arc Modeling Progress
HEAF testbed and diagnostics set-up 29 Experimental Schematic Optical emission spectroscopy OES spectra C2 SWAN bands N2 Cu (I)
Cu (I),
N (II)
Emission from excited atomic and molecular species detected
Spectroscopic Arc Temperature Inference from Cu Vapor 30 Time-resolved temperature inferred from spectral features and associated errors Implies temperature inferred from metallic atoms is higher than from broadband emission 6000-7000 K temperature is in agreement with Aria model 6900 K and prior literature (6200-7200 K)
Dependence of graybody and spectral temperature on arc current
Progress towards the next Aria arc-fault simulation benchmark is underway, which will utilize the arc current as an input parameter to replace the pre-defined volumetric heating source.
This approach requires real-time calculations of the current density to evaluate the evolution of ohmic heating and calculate the temporal physics of arcs in a fully self-consistent way.
After these developments, we plan to steadily incorporate components of the momentum and mass balance equations to allow for inclusion of convective energy transport, necessary for accurate representation of free burning arcs.
Beyond this physics, we will include convective energy transport, magnetic forces and the influence of electrode surfaces on the arc From this physics-based arc energy source term, radiation and conductive heat transport allow:
Calculation of volume of electrode melted/vaporized Calculation of equipment breach time (time to Tmelt)
Calculation of spatial characterization of temperature field and heat flux This work will address large gaps in current arc flash studies and improve realism:
Energy contribution from metal electrodes is ignored Enclosure is assumed to be open Modeling Next Steps 31
Target Fragility and Failure Criteria
Failure Criteria 33
- Failure Criteria is independent of energy release prediction/calculation/measurement from HEAF
- Failure Criteria is a characteristic of the target equipment
- Target Equipment list will be developed by the joint NRC/EPRI Working Group Target Temperature/
Time Incident Energy/time Breakdown strength Cables TS NA Cables TP NA Cable tray NA Transformers Switch Gear Electrical cabinets 0
50 100 150 200 250 300 350 400 450 500 0
5 10 15 20 25 30 35 Heat Release Rate (kW)
Time (minutes)
Comparison of Heat Source Term Profile Traditional Switchgear and load center fire HEAF 10000
Cable Failure Criteria 34
- NUREG/CR-6850 based on typical fire growth HRR of exposing fire
- Cable failure time is when insulation reaches criteria temp
- Thief Model and 6850 Empirical Approach for short duration not sufficient for HEAF durations and energy release
- Approach:
- Predictions for a thermoset and thermoplastic cable will be made for a range of incident energy values to determine range when cable meets critical temperature when exposed for HEAF durations.
- Confirmatory tests will be conducted measuring under-jacket temperature and monitoring of circuit in parallel cables
- Incident energy will be provided by most appropriate source to HEAF emitted energy Radiant Heat Temperature TP 6 kW/m2 205 C TS 11 kW/m2 330 C Exposure Temp Time to Failure(min)
Heat Flux kW/m2 Time to Failure(min)
TS: XLPE Rockbestos Firewall III
>490 C 1
>20 1
TP: PE insulated cables
>370 1
>16 1
Sandia National Labs Model Information
Sierra Mechanics
- Sierra is an engineering mechanics simulation code suite supporting the Nations Nuclear Weapons mission as well as other customers
- Multiple codes based on a common foundation of mesh generation, input syntax, parallel processing, and communication utilities
- Solid mechanics: Implicit quasi-statics, implicit dynamics, explicit dynamics
- Structural dynamics
- Thermal/fluid:
- Aria: Thermal, incompressible fluid dynamics, multiphysics
- Fuego: Reacting low-Mach fluid dynamics
- Aero: Compressible, high-Mach fluid dynamics
- Nalu: Low-Mach fluid dynamics, open-source
- Cubit: Mesh generation
- Paraview: Simulation visualization
- Coupling between Sierra codes and to select other codes (CTH, etc).
Sierra/Multiphysics: Aria 37
- Aria is a multi-physics, finite-element method code
- Origins are GOMA, which was created for manufacturing (welding, coating, etc.).
- Fully parallel with MPI, scales to 1000s of cores
- Full-Newton nonlinear solution scheme
- Variety of direct and iterative linear solvers (Trilinos)
- Solved a variety of equations with varied couplings
- Conservation of energy, mass, momentum (fluid), momentum (solid)
- Species transport, generalized chemistry, voltage, current
- Level-set, radiation transport, porous flow, lubrication, etc.
- Traditionally FEM with P0, Q1, Q2 basis functions.
- Monolithic & loose couplings (equation systems, solution control)
- Coupled to many other Sierra codes (Adagio, Fuego, Cantera)
Aria: Conductive burn of energetic materials 38 Physics
- Reaction chemistry
- Interface physics
- Compressible gases
- Solid mechanics P (Pa) 0 W. Erikson
SIERRA/Fuego/Syrinx/Calore Methodology and Framework
- Common application framework
- Shared data structure, parser, file I/O, parallel communication, solvers, etc.
- Data exchange for application coupling
- SIERRA/Fuego: Low-Mach turbulent fire
- Hybrid control volume finite element method (CVFEM)
- SIERRA/Syrinx: Participating media radiation (PMR)
- Streamwise-upwind Petrov-Galerkin FEM
- SIERRA/Calore: Heat conduction, enclosure radiation
- Galerkin FEM Each code has completed a detailed verification suite!
Fluids Numerical Overview CVFEM
- Backward Euler or Crank-Nicholson time solution
- Equal-order interpolation CVFEM technique for low-Mach and moderately acoustically compressible mechanics
- Approximate pressure projection method for continuity/momentum
- Generalized Newton solve (full analytical sensitivities) with pressure stabilization
- Convection operators: Central, pure upwind, skew upwind, MUSCL w/flux limiters, SUCV Continuity:
Momentum:
Enthalpy:
Species:
Turbulence closure models required Chemistry and subgrid mixing model
Use Case: Hawaii Lead Acid Batter System on Fire (2012; 30Mil cost)
- Racks of lead acid batteries and power conditioning system inside the building
- No emergency response (Hawaii is a closed water system)
In what context could we imagine a computational capability being useful?
Can ASC-based tools be deployed to this application space?
Image Source: WindPower Monthly http://www.windpowermonthly.com/article/1284038/analysis-first-wind-project-avoids-storage-30m-fire Prior Aria/Fuego coupling:
Battery Safety Large-scale Storage Facilities
Fire Modeled as a combustible hydrocarbon Ventilation (flow in)
Ventilation (flow out)
Object heat up Inner Pressurizing fluid (buoyant)
Outer Heat flux Racks of cells Applying Sierra Simulation Tool to Battery Fire Scenarios
Ventilation Effect on Fire Plume Dynamics (0 m/s)
Ventilation Effect on Fire Plume Dynamics (10 m/s)
Questions