Arc Flash Compliance Implementation at Mining & Minerals Processing Facilities

Transcription

1 Arc Flash Compliance Implementation at Mining & Minerals Processing Facilities David B. Durocher, Senior Member, IEEE Global Industry Manager, Mining & Minerals Eaton Corporation SW Kinsman Rd Wilsonville, OR USA 2013 WMEA Conference November 21-22, 2013 Albuquerque NM

2 Overview: Four Cases Studies Involving Arc Flash Case Study 1: Enterprise Arc Flash Compliance for a global cement manufacturing business 13 plants in North America Case Study 2: Challenges in completing and Arc Flash Compliance at an open pit copper mine in the USA Case Study 3: Review of an Arc Flash incident at a chemical processing facility the hazards of unplanned energized work Case Study 4: Safety by Design, best practices in reducing Arc Flash hazards at a coal preparation plant in New South Wales Australia Review business challenges and lessons learned

3 Case #1: Arc Flash Compliance, Cement Plants Background: Global Cement Producer Compliance program for 14 plants in the USA and Canada Why Implement? (Not MSHA regulated considered part of the mining industry) Center Led Review of Corporate Culture Build Awareness at All Levels of the Enterprise Development of a Common Arc Flash Compliance Concept Document Timeframe Stakeholders Review and Approval

4 Case #1: Arc Flash Compliance Standards Arc-Flash Calculations and Workplace Safety Standards NFPA70E-2012 IEEE CSAZ

5 Arc Flash Compliance Concept Document To Gain Internal Understanding and Consensus Review of Applicable Codes and Standards Common Understanding of Arc Flash Hazards and Levels Required Electrical Documentation to Complete Study Equipment Labels Overview of PPE Change in Work Procedures Change in Practice Equipment Purchase Maintenance Installation Typical Equipment Label

6 Advantages of Scale for Various Work Processes Why Use Global Engineering Service Company versus Local Engineering Firms? Experience in Cement / Mining Industry Depth of Knowledge Consistency and Footprint Match Type of Skill Sets Available for Various Work Processes Field Service Engineers Power Systems Engineers Asset Optimization Knowledge Management Integrated Project Solutions Power Systems Engineering Solutions Power Systems Modernization New Equipment Services Field Services

7 Scope of Work Arc Flash Compliance Supplier Scope of Work Power System Study Field Data Collection Codes & Standards Use of Power System Engineers (Code Deficiencies, Reliability) Accuracy Elimination of Multiple Trips Modeling & Recommendations Centralized Power Systems Engineering Group Consistency in Study Methodology & Reports Single Point of Contact Arc Flash Hazard & Over-Dutied Equipment Field Implementation Including Labeling Site Safety Training

8 Scope of Work Arc Flash Compliance Site Safety Training Arc Flash and Electrical Safety Working On or Near Energized Electrical Equipment Arc Flash Study Results Discuss Changes to Company Safety Policy Due to NFPA 2012 Work Process Changes Work Permit Identification and Use of Qualified Personnel

9 Scope of Work Identify Areas for Concern Arc Flash Results Device Name Bus kv Bus Bolted Fault ka Device Bolted Fault ka Arcing Fault ka Trip Time (s.) Bkr. Opening (s.) AF Boundary Working Distance (in.) Incident Energy (cal/cm 2 ) 416MCC-50/51-51G #2 FDR #3 SQD PNL DANGER FDR #4 BULK SILO #0 FDR #2 PHMCC #0 FDR LCS#4 4A #2 RLY U9_ #2 FDR LCS#2 2D #2 FU PUMPS1/ #0 FDR LCS#4 1B #1 COMP SUB MN #3 RELAY COMP 50/ DANGER FU DIST PANEL #0 FU QUARRY MCC A #0 M3_004_2A #3 FDR #2 PHMCC #0 T_M2_001_FUSE dependent on: #3 T_M2_001_FUSE #3 T_M1-101 FUSE #3 T-M1-102 FUSE arc location 19.6 #3 T_M1-201 FUSE #3 T_M1-201 FUSE from the 41.5arc DANGER T-M1-202 FUSE DANGER T_M1-204 FUSE cal/cm PPE DANGER M3_003_1B 40 cal/cm exposure PPE #3 T_M1_203_FUSE DANGER HRC The heat reaching the skin is 1) The power of the arc at the 2) The distance of the worker 3) The time duration of the arc

10 Recommendations After Completion of Studies Updated Technology for System Improvement Hazard Rating Category Above 40 cals/cm 2 Modify Setting on Existing Relays & CB s Replace CB Trip Units with Modern Trip Units with Maintenance Mode Replacement of Medium Voltage Substation Fused Switches with Vacuum Circuit Breakers Use of Arc Resistant Switchgear Assemblies

11 Technologies/Upgrades to Reduce Arc-Flash Hazard 2000kVA Unit Substation Addition of 50/51 Overcurrent Relay Design Limitations Secondary bus fault protection Secondary bus overload protection NEC Article (C)2 Allows unprotected secondary conductor Transformer Secondary Conductors not over 3 meters long

12 Technologies/Upgrades to Reduce Arc-Flash Hazard Power Distribution technologies to Reduce Arc-Flash Hazards Arc Flash Reduction Maintenance System Substation Primary Vacuum Circuit Breaker

13 Project Time Horizon: A Planned Commitment Build Need Throughout all Levels of Enterprise Supplier Selection Scope of Work, DOR, Schedule, Milestones Continue Execution Finish Remaining 6 Locations, Conduct Lesson Learned and Share Development of Arc Flash Criteria Document Review and Approval of Operations Personnel Execution of Project Conduct Pilot Test, Make Changes, Continue Project at 7 Locations. Begin Annual Audits Every Location Was Visited, Develop Phased Approach for Remediation Where Necessary.

14 Case #1: Lessons Learned - Success Factors Assured buy-in at all levels via early engagement with company corporate and plant site leadership (Arc Flash Criteria document nearly two years in advance of project execution) Execution of the project only after a well-developed project scope document was established and circulated Set clear expectations of the plant sites and the global services provider on schedule and costs of the project Selecting a service provider with the appropriate scale with the local presence to efficiently execute to meet the project schedule. Aligned with a supplier with capabilities both in engineering services and product technologies available to assist in managing the arc flash hazard down for critical plant systems. Leveraged scale across the enterprise, driving standards for data collection, studies, reports, labels and also site safety training.

15 Case #2: Arc Flash Compliance Open Pit Mine Background: Global Miner Compliance program for large copper mine in Arizona USA (led by one individual!) Accident rate in the mining industry 3 to 7 times greater Incentives Family history Personal experience Education Management Workforce

16 Case #2: OSHA versus MSHA OSHA Code of Federal Regulations Title 29, Part 1910, Subpart (S), Occupational Safety & Health Administration (OSHA) recognizes NFPA-70E, Standard for Electrical Safety in the Workplace MSHA Code of Federal Regulations Title 30*, Part 56, Subpart K, The Mine Safety and Health Administration (MSHA) is responsible for enforcing electrical safety in mining operations * Note: CFR 30 does not reference personal protective equipment (PPE) to protect electrical workers.

17 Case #2: Step by Step Procedure Collect the system and installation data Determine the system modes of operation Determine the bolted fault currents Determine the arc fault currents Find the protective device characteristics and duration of the arc Document the system voltage and classes of equipment Select the working distance Determine the incident energy Determine the flash-protection boundary Data Collection System Modeling Analysis

18 Case #2: Data Collection Rugged Terrain Equipment spread over several square miles Creating an accurate model Documenting deficiencies: Over-dutied equipment Overloaded cables Improper over current device settings

19 Case #2: Data Collection - Challenges Long distance between poles Difficult terrain Large equipment Snakes! Wheel Chock

20 Case #2: Data Collection, View of the Pit Distribution loop runs around the perimeter of the pit Radial feeds from loop serve equipment

21 Case #2: Data Collection, Shovel 101 Shovel Shovel

22 Case #2: Data Collection 2 miles! Radial Feed Shovel

23 Case #2: Creating an Accurate Model Mobile substations Pole-mounted distribution feeders using odd size wire (several kilometers long) Portable shovel trailing cables (up to 1500 meters long)

24 Case #2: System Analysis, Trailing Cables Trailing Cable Shovel Box

25 Case #2: System Analysis, Trailing Cables Shovel Box Feed Through Pot Head Mobile shovel box feeding shovel 7200 V Fed from perimeter loop Over Current Relay Power Meter Ground Check Monitor

26 Case #2: System Analysis Considerations Consider all possible ways electrical workers interact with energized equipment. Trailing cables are moved or repositioned with hook stick while energized. How is the electrical worker contacting the cable and at what distance from the source? Calculated incident energy and arc flash boundary at various points along the length of the conductor Recognized that the worst-case arc flash hazard may not correspond to the highest fault currents

27 Case #2: Arc Flash Mitigation Lower protective device pick-up where possible, while maintaining selectivity The easiest way to lower incident energy is by reducing the operating time of the over current device. Increases awareness of equipment condition and maintenance schedule Several other methods: Should be considered on a case by case basis

28 Case #2: Lessons Learned - Success Factors One person can in fact make a difference in pushing to improve a culture, including a culture to make a commitment to life safety The mining industry often involves mobile equipment where multiple scenarios should be considered to assure calculations are accurate System changes can impact the risk. Permanent labels indicating required PPE in a dynamic system can improve safety, but also can present a chance for mistakes down the road Added benefits including increased awareness of required periodic maintenance and identification of over-dutied system equipment can be realized from completion of an arc flash hazard assessment

29 Case #3: Chemical Processing Plant - Overview Background: US Chemical Plant Review of an Arc Flash incident occurring during energized work Illustrates what can be achieved by properly applying Workplace Safety (NFPA 70E) Demonstrates you must plan for the unplanned event Supporting evidence that state of the art technology can save lives and equipment

30 Case #3: Chemical Processing Plant Set-up Extensive Rework of 480 Volt Distribution System Last Portion Of Project Included Removal of a 3- Conductor Cable From Energized Gear Section Where Work Would Be Performed Was De-Energized Upstream Breaker Employed Arc Reducing Technology Cubicle 1 Cubicle 2 Cubicle 3 Cubicle 5 De-energized Cubicle 9 Cubicle 13 Cubicle 17 Cubicle 6 De-energized Cubicle 7 De-energized Cubicle 4 Cubicle 8 De-energized Cubicle In Which Work Was Being Performed Cubicle 10 Cubicle 14 Cubicle 18 Cubicle 11 Cubicle 15 Cubicle 19 Cubicle 12 Cubicle 16 Cubicle 20 Physical Layout of this Situation Is Important To Understanding The Sequence of Events

31 Case #3: Working Conditions 1000kVA Transformer Upstream 21,000 Amps of Available Fault Current Energy: 17.7 Cal/cm2 : No Arc Reducing Technology 2.9 Cal/cm2 : With Arc Reducing Technology PPE Utilized - 8 Cal 40 Cal/cm 2 & Less 8 Cal/cm 2 & Less

32 Case #3: Arc Reducing Technology Upstream Switch Utilized When Needed Employs Technology To Clear Fault Faster Than Microprocessor Based Instantaneous Reduced Energy From 17.7 Cal/cm2 to 2.9 Cal/cm 2 Maintenance switch total clearing time = 40ms

33 Case #3: Leveraging Workplace Safety (NFPA-70E) Pre-Planning Included Reviewing the Safety Plan Built From The Foundation of NFPA 70E NFPA 70E Section 130.4(A) and 130.5(B): A shock and arc flash work hazard analysis was performed NFPA 70E section 120.2(D)(2): Complex lockout and safe work permit was required / obtained Project plan review was conducted prior to work being performed Cable was removed from cable tray exiting the switchgear before work in the switchgear began

34 Case #3: Planned Tools and Equipment Arc Reduction Technology upstream of switchgear would be utilized Rope and/or other non conductive equipment would be utilized for work Only Qualified Persons were utilized for this project The Tools Used On Any Project Are Important To The Success of That Project

35 Case #3: The Unplanned Event The Rope Method Was not Working Team Secured A Come Along The Come Along Was Not An Approved Tool Per The Work Permit This Product Was Conductive

36 Case #3: The Arc Flash Event Cubicle 1 Cubicle 5 De-energized Pulling cable out of top of this cubicle Cubicle 9 Cubicle 13 Cubicle 17 Come Along Chain Extended Below Cubicle 5 But Drifted Into Cubicle 4 Cubicle 2 Cubicle 3 Cubicle 4 (Energized Cubicle Where Fault occured) Cubicle 6 De-energized Cubicle 7 De-energized Cubicle 8 De-energized Cubicle 10 Cubicle 14 Cubicle 18 Cubicle 11 Cubicle 15 Cubicle 19 Cubicle 12 Cubicle 16 Cubicle 20 Chain From Come Along Became Energized In Cubicle 4 Chain From The New Tool Drifted Into an Energized Cubicle Causing The Event

37 Case #3: Post Event Analysis Plant Shut Down No Loss of Equipment No Loss of Life or Injury Overall Damage Was Minimal Re-Energizing Was Quick The Event Itself Was Not Desired Given the Potential, The Results Were A Relief To All Involved

38 Case #3: Lessons Learned Planning for the Unplanned Event Mistakes will happen on even the best planned projects. A change in tool lead to this event. Applying Workplace Safety Standards Proper planning and leveraging of all accessible resources prevented what could have been a catastrophic arc flash incident Leveraging Technology Reducing the available energy in case of a mistake anticipated an unforeseen problem occurring and maximized the uptime of this plant

39 Case #4: Coal Prep Plant NSW Australia Greenfield Preparation Plant Challenge Corporate directive to reduce cost of capital for expansion of New South Wales coal mine New coal prep plant goal: Lead the industry in safety

40 Safety by Design: Low-Voltage MCCs Type Tested to IEC (IEC criteria 1 through 7)

41 Safety by Design: Low-Voltage MCCs (IEC) Arcing Current = 5.6kA Normal: HRC = 3 (11 cal/cm 2 ) Maintenance: HRC = 1 (3 cal/cm 2 ) Type Tested to IEC (IEC criteria 1 through 7) Internal Arc Classified Assembly!

42 Safety by Design: Low-Voltage MCCs (ANSI) Only Two LV MCC Activities While Energized 1) Insertion/Removal of starter unit from energized bus 2) Troubleshooting with starter unit door open Integral Racking Device Unit Door Open Connected-Test-Disconnected LV MCC UL485 Arc-Resistant designs?? ANSI C does not apply! CSA C22.2 No does apply! Eaton Freedom Low-Voltage Metal-Enclosed MCC Arc Flash Reduction Maintenance Switch Recommendation: Specify integral unit racking and ARMS!

43 Case #4: Coal Prep Plant Success Low-Voltage MCC Integrated e-house Maintenance Switch Low-Voltage AF Drives Integrated e-house with restricted access to only qualified persons Arc Reduction Maintenance System for all LV MCCs Low-voltage AF drives through 900KW for energy efficiency

44 Case #4: Lessons Learned Take the opportunity to apply the latest technologies designed to address Arc Flash for new construction. For both ANSI/NEMA and IEC low and medium-voltage assemblies, arc resistant designs should be considered, especially for Greenfield sites. Assure that only qualified persons have access to areas where an arc flash event might occur is a best practice for both new and existing industrial facilities

45 Conclusions It is important to understand the hazards of Arc Flash, the Standards and importance of implementing a compliance program Understand the proper steps in effectively modeling electrical systems and leverage scale to assure repeatable processes New technologies have proved effective in mitigating arc flash hazards for both existing and Greenfield sites. New construction provides a unique opportunity to design electrical systems based on a safety by design approach which should be leveraged for any new project, since the cost to remedy system deficiencies after the fact comes at a significantly higher cost.

46 Arc Flash Compliance Implementation at Mining & Minerals Processing Facilities Questions? David B. Durocher, Senior Member, IEEE Global Industry Manager, Mining & Minerals Eaton Corporation SW Kinsman Rd Wilsonville, OR USA