Date post: | 27-Dec-2015 |
Category: |
Documents |
Upload: | quentin-miller |
View: | 213 times |
Download: | 0 times |
SWEDE Tulsa May 8th, 2009 Dennis Keilbarth
Overhead Distribution Arc Flash at PSO
Overhead Distribution Arc Flash at PSO
2 2
OverviewOverview
• Introduction/Background
• Technical overview
• Engineering and policy solutions
• Ongoing work
• Conclusion
3 3
Public Service Company of Oklahoma
Public Service Company of Oklahoma
• 527,000 Customers
• 4405 MW Generation
• 3700 mi Transmission
• 21,857 mi Distribution
• 1712 Employees
• Headquarters in Tulsa
• 96 Years Old
4 4
American Electric PowerAmerican Electric Power
• 5 Million Customers
• 11 States
• 38,000 MW Generation
• 39,000 mi Transmission
• 208,000 mi Distribution
• 20,000 Employees
• Headquarters in Columbus Ohio
• 102 Years Old
5 5
PSO’s Arc Hazard ProgramPSO’s Arc Hazard Program
• Dedicated teams • Generation
• Transmission and Substations
• Network Distribution
• Metering
• Overhead Distribution and Underground Residential (URD)
6 6
Overhead and URD StrategyOverhead and URD Strategy
• Purpose• Improve safety/reduce hazards• NESC National Electric Safety Code compliance
• Considerations• Consistency across distribution operating
districts• Consistency across GT&D business units• Trade-offs: don’t introduce new safety hazards
7 7
Arc Flash OverviewArc Flash Overview
• Significant Parameters• Fault Current
• Clearing Time
• Distance
• Voltage
• Measured in cal/cm2
• “Incident Energy”
• 1.2 cal/cm2 = 2nd degree burn on bare skin
Image provided by Southern Company
8 8
Technical OverviewTechnical Overview
Calories/cm2 Calculations
Clearing times 2 to 60 cycles
Fault Current 1000 to 20,000 amps
Fault Current (kA) Cal/cm2 Cal/cm2 Cal/cm2 Cal/cm2 Cal/cm2 Cal/cm2 Cal/cm2 Cal/cm2 Cal/cm2 Cal/cm2
20 2.49 4.99 7.48 9.97 12.47 24.93 37.40 49.87 62.33 74.8019 2.31 4.62 6.93 9.24 11.55 23.10 34.65 46.20 57.75 69.3018 2.13 4.27 6.40 8.54 10.67 21.34 32.01 42.68 53.35 64.0217 1.96 3.92 5.87 7.83 9.79 19.58 29.37 39.16 48.95 58.7416 1.79 3.58 5.37 7.16 8.95 17.89 26.84 35.79 44.73 53.6815 1.63 3.26 4.88 6.51 8.14 16.28 24.42 32.56 40.70 48.8414 1.47 2.95 4.42 5.90 7.37 14.74 22.11 29.48 36.85 44.2213 1.33 2.65 3.98 5.31 6.64 13.27 19.91 26.55 33.18 39.8212 1.18 2.36 3.54 4.72 5.90 11.81 17.71 23.61 29.52 35.4211 1.05 2.10 3.15 4.19 5.24 10.49 15.73 20.97 26.22 31.4610 0.92 1.83 2.75 3.67 4.58 9.17 13.75 18.33 22.92 27.50
9 0.79 1.58 2.38 3.17 3.96 7.92 11.88 15.84 19.80 23.768 0.67 1.35 2.02 2.70 3.37 6.75 10.12 13.49 16.87 20.247 0.56 1.13 1.69 2.26 2.82 5.65 8.47 11.29 14.12 16.946 0.46 0.92 1.39 1.85 2.31 4.62 6.93 9.24 11.55 13.865 0.36 0.72 1.08 1.44 1.80 3.59 5.39 7.19 8.98 10.784 0.27 0.54 0.81 1.09 1.36 2.71 4.07 5.43 6.78 8.143 0.18 0.37 0.55 0.73 0.92 1.83 2.75 3.67 4.58 5.502 0.10 0.21 0.31 0.41 0.51 1.03 1.54 2.05 2.57 3.081 0.04 0.07 0.11 0.15 0.18 0.37 0.55 0.73 0.92 1.10
Clearing Time (cycles): 2 4 6 8 10 20 30 40 50 60
12 12
System SummarySystem Summary
4 cal 8 cal 12 cal 25 cal 40 cal
Reclosers 95% 100%
Fuses 98% 99% 100%
Breaker Zones 5% 20% 60% 99% 99%
Breaker Zones (NRO)* 75% 98% 99% 99% 99%
* NRO = Non-Reclose Order
13 13
SolutionsSolutions
• Increase Distance• 6ft+ hotstick
• Reduce Clearing Time• Place devices in non-
reclose
• Some electronic relays have fast trip settings• (Hot Line Tag)
• Looking to deploy in high hazard zones
14 14
SolutionsSolutions
• Cover-up• Reduce chances of
poly-phase faults• Watch for damaged
equipment while applying
• PPE • Personal Protective
Equipment• Last line of defense
15 15
PPE SolutionsPPE Solutions
Traditional PSO Requirements:• 4 cal/cm2 FR shirt, Hardhat, Safety Glasses
New Additional Requirements:• 8 cal/cm2 (total) layered FR shirt system • Breaker zones require NRO unless a specific
analysis has been performed on a breaker without an NRO, with a <= 8 cal result.
16 16
Ongoing WorkOngoing Work
• Develop internal web resources for arc flash information
• Training videos
• Testing• Clothing system combinations
• Effects of reclosing, HLT, and other devices
17 17
ConclusionConclusion
• Simple, consistent solutions that fit across a wide range of facilities and work practices
• Achieve the largest safety gains possible while considering the big picture trade-offs
• Be prepared to refine processes as new information becomes available
• Always look to “engineer-out” the hazards