Two Recent Case Studies in the Mining Industry

Transcription

1 Two Recent Case Studies in the Mining Industry Remote Isolation Arc Flash Remediation David B. Durocher Senior Member, IEEE Global Industry Manager, Mining Eaton Corporation SW Kinsman Rd Wilsonville, OR USA

2 Case Study #1: Remote Isolation October 2016 IEEE IAS Mining Industry Conference Paper Traditional Isolation on a Mining Conveyor Switchroom Safety Rated Controller Motor Control Center Control Signal Power Cable Motor Drive 2

3 The Case for Change Case Study: ASARCO Mission Arizona Copper Mine 2013 upgrade project: replace 5kV air magnetic switchgear 1960 s vintage obsolete air-break switchgear Parts were no longer available Loads were 1960 s vintage 4.16kV MCCs with manual isolation switch, fuse, air-break contactor Service of downstream MCCs presented a significant safety hazard Narrow Design: 2-high to 2000A, 5kV 26 (660.4mm) wide 95 (2413mm) high or 80 (2032mm) high New 5kV vacuum switchgear installation 3

4 The Case for Change Case Study: ASARCO Mission Arizona Copper Mine Leveraging new technology Integral motor is part of the breaker cell Racking of breakers and auxiliaries (CPT, VT) Pendent station or remote (connect, test, disconnect) Optional pendant station Integral motor operator in breaker cell New 5kV vacuum switchgear installation 4

5 The Case for Change Case Study: ASARCO Mission Arizona Copper Mine Marshalling panel installed in adjacent room Kirk Key at 5kV vacuum circuit breaker. Operator applies lock here after breaker is disengaged from bus Open-Close-Trip breaker control switch PBs to rack breaker and lights indicating Connected-Test- Disconnected 5

6 A Look at Existing US Lockout/Tagout Standards NFPA70E: Electrical Safe Work Condition. OSHA: The control of hazardous energy (lockout/tagout). Article 100: A state in which an electrical conductor or circuit part has been disconnected from energized parts, locked/tagged in accordance with the established standards, tested to ensure absence of voltage, and grounded if determined necessary. Basis is to protect against the risk of injury from electrical hazards (c)(3)(i) When a tagout device is used on an energy isolating device which is capable of being locked out, the tagout device shall be attached at the same location that the lockout device would have been attached MSHA: Work on electrically powered equipment 30 CFR 56/ Power switches shall be locked out or other measures taken which shall prevent the equipment from being energized without the knowledge of the individuals working on it 6

7 Leveraging Integral Racking/ Remote Isolation Many mine sites have electrical loads that are kilometers from electrical switch rooms Existing systems are often antiquated and nearing end of life Isolation takes time and presents a significant workplace safety risk due to potential arc flash hazards 7

8 Remote Isolation Integration on a Conveyor Safety Rated Controller 8

9 Field Isolation Station Overview Mimics traditional lockout/tagout and try of traditional switch room isolation The system is operated by nonelectrical personnel Switch room includes warning alarms to evacuate prior to isolation 9

10 Field Isolation Station Sequence of Operation 1) Request to Isolate 2) Requesting/Approved 3) Checking/Proceed 4) Isolate 5) Try 6) Lift Flap/Lock & Tag 10

11 Safety Controller & Rated Hardware 11

12 Global Functional Safety Standards 1) Two points of Isolation 2) Complies with industry functional safety standards IEC Safety of Machinery Electrical Components IEC Functional Safety of electrical/electronic/programmable electronic safety devices (for SIL rating) IEC Safety of Machinery Functional Safety of safety-related electrical, electronic & programmable electronic systems NFPA 70E Reducing exposure to injury from electrical hazards ANSI/ISA IEC Functional Safety Safety instrumented systems for the process industry sector 12

13 Case Study: Port Hedland, Western Australia 13

14 Case Study: Conveyor Tunnel Portals 14

15 16 mile trip from portal to portal 15

16 Field Isolation Station on Conveyor 16

17 Existing Switchgear Retrofit Before After 17

18 MV Switchgear Truck Conversion Before During After 18

19 No. of Isolations per month Summary of Case Study Production Benefits 80 Production Gains with Remote Isolation Conventional isolation time (Mins) 3 Remote IsolationTime (Mins) Monthly Production (KT) Derived No. Monthly Isolations Gained Production in Kilo Tonnes (KT) 45 Time lost using existing system for isolations INVESTMENT BREAK EVEN POINT Tonnes per hour Isolations per month Conventional isolation time (Mins) 42 Number of isolations to break even Days to break even Minimum REMSAFE isolation time (Mins) Gained production time (Mins) with Remote Isolation ,

20 Case Study #2: Arc Flash Remediation May 2017 IEEE IAS Cement Industry Conference Paper Global Cement Producer Arc Flash Compliance program for 14 plants in the USA and Canada * Center Led: Arc Flash Compliance Document Review of corporate culture Build awareness at all levels of the enterprise Supplier Scope of Work Document Field Data Collection Modeling & recommendations Site implementation labels Safety training * G.M. Kemper, W.S. Vilcheck, D.B Durocher, The Journey of an Enterprise in A Process Industry Toward Improved Electrical Workplace Safety," IEEE Transactions on Industry Applications,

21 Electrical Workplace Safety Standards Arc-Flash Calculations and Workplace Safety Standards NFPA70E-2015 IEEE CSAZ

22 After Completion of 14 Plant Studies Affix labels from arc flash study so workers are aware of the hazard and required PPE Company issued uniforms (8 cal/cm 2 ) and PPE suit for higher hazards (40 cal/cm 2 ) For calculated hazard areas above 40 cal/cm 2 Easy/Lower Cost Modify Setting on Existing Relays & CB s Not Easy/Higher Cost Replace MV and LV switchgear and CB s to modern devices IMPLEMENTATION PRIORITY CRITICAL: Issue must be addressed immediately. HIGH: Address issue within 4 months. MEDIUM: Address issue within one year. LOW: Address issue within 5 years or monitor situation only. 22

23 Project Deliverables Identify Areas for Concern Arc Flash Results Device Name Bus Device Bkr. Working Incident Arcing Trip Time AF Bus kv Bolted Bolted Opening Distance Energy Fault ka (s.) Boundary Fault ka Fault ka (s.) (in.) (cal/cm 2 ) HRC 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 The 18 heat 0.8 reaching the #0 skin is T_M2_001_FUSE dependent on: #3 T_M2_001_FUSE #3 1) The power of the arc at the arc T_M1-101 FUSE #3 location T-M1-102 FUSE #3 2) The distance of the worker from T_M1-201 FUSE the arc 17.7 #3 T_M1-201 FUSE ) 24 The time 41.5 duration DANGER of the arc T-M1-202 FUSE cal/cm PPE exposure 41.9 DANGER T_M1-204 FUSE cal/cm DANGER M3_003_1B 0.48PPE #3 T_M1_203_FUSE DANGER 23

24 Arc Flash Remediation by one Plant in Canada One plant Authorization for Expenditure (AFE) to upgrade ten LV substations Ten (10) critical Low Voltage Substations identified as high incident energy areas where upgrades to reduce the hazard were identified Local service provider was selected to provide turn-key install 24

25 Issues with Low Voltage Substations Safety: Unit Substation Design Typical LV Substation with Fused Load-Break Switch Arc Flash Study Results 13.8kV 480Y/277V 1200A 125E 2000kVA 5.75%Z 3200A 1200A 1200A 1200A Fault at 480V Switchgear Bus 31.8kA Symmetrical Fault current 1167 AF Boundary UNAPPROACHABLE: IEEE & NFPA70E-2015 No PPE available 25

26 One Plant s Remediation: Fused Switch Retrofit Improved Unit Substation Design 15kV Vacuum Breaker LV Substation with Retrofit Vacuum Primary Breaker 50/51 Relay 86 ST Integral 50/51 Relay Before After Arc Flash Study Results Sym. Fault at 480V Switchgear Bus 31.8kA 31.8kA AF Boundary Cal/cm NFPA70E HRC UNAPPROACHABLE 1 26

27 Medium-Voltage Substation Upgrades MV Switch Upgrade 10 Locations Remove fuses from switch Retrofit in Mini vacuum breaker with external relay trip Relays have ARMS switches which allow for greater protection for personal performing maintenance/troubleshooting tasks 27

28 Cement Plant Arc Flash Remediation MV Switch Upgrade Primary CTs added to MV compartment Primary fuses removed from fused load-break switch New Eaton VCP-T Vacuum Circuit Breaker Installed, replacing fuses 28

29 Cement Plant Arc Flash Remediation Substation MV Switch Upgrade Secondary CTs added to transformer bus Wall mounted enclosure with breaker controls, ARMS switch & light and 50/51 overcurrent relays for primary & secondary protection 29

30 Upgrade Secondary Main LV Circuit Breakers LV Breaker Upgrade 5 Locations Replace old circuit breakers with limited selectivity on trip units with new breakers that have updated trip units Trip Units have ARMS switches which allow for greater protection when engaged by personal performing maintenance/troubleshooting 30

31 Upgrade Secondary Main LV Circuit Breakers LV Breaker Upgrade Arc Flash Reduction Maintenance System LV Switchgear assemblies upgraded with new main circuit breakers with AMRS RESULTS: Substation Arc Flash Incident Energy Reduced from 100 to 130 cals/cm 2 to below 8 cal/cm 2 in critical areas. 31

32 LV Substation Single Line Diagram Primary/Secondary Overcurrent Relays Arc Flash Reduction Maintenance System 32

33 Arc Flash Study Updated 10 Upgraded Low-Voltage Substations Bus Name 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 ) MCC 2408E (Line) RLY SUB2402E ' 8" MCC 2408E (ARMS) RLY SUB2402E ' 8" MCC 2413E (Line) RLY SUB2403E ' 9" MCC 2413E (ARMS) RLY SUB2403E ' 5" 18 7 MCC 2436E (Line) RLY SUB2404E ' 2" MCC 2436E (ARMS) RLY SUB2404E ' 5" 18 7 MCC 2430E (Line) RLY TX-A ' 12" MCC 2430E (ARMS) RLY TX-A ' 7" BUS A2 2500A RLY SUB2432E ' 11" BUS A2 2500A (ARMS) RLY SUB2432E ' 2" MCC 2457E (Line) RLY SUB2457E ' 1" MCC 2457E (ARMS) RLY SUB2457E ' 12" MCC 2475E (Line) RLY SUB ' 7" MCC 2475E (ARMS) RLY SUB ' 2" SEC SUB 2490 (Line) RLY SUB ' 11" SEC SUB 2490 (ARMS) RLY SUB ' 2" Bus 2445 T1 SEC (Line) RLY T1 01/ ' 7" Bus 2445 T1 SEC RLY T ' 7" Bus 2445 T1 SEC (ARMS) RLY T1 01/ ' 2" Bus 2445 T2 SEC (Line) RLY T2 01/ ' 7" Bus 2445 T2 SEC RLY T ' 7" Bus 2445 T2 SEC (ARMS) RLY T2 01/ ' 2"

34 New Grinding Mill Addition Electrical Equipment Designed for Safety LV Switchgear New Low Voltage Substation 34

35 Results from Arc Flash Compliance Project Expected results Ability to perform energized work safely Improved safety during lockout/tagout Unexpected results New relay protection perhaps too effective Video 35

36 Other Electrical Issues Identified Ground Grid As found Ground rods unearthed, damaged or heavily oxidized Severe ground grid damage 36

37 Other Electrical Issues Identified Ground Grid As found ohms resistance between grid and ground conductors (should be 1-2 ohms) 37

38 Other Electrical Issues Identified 5kV Cables As found Significant corona damage 38

39 Other Electrical Issues Identified 5kV Cables As found and replaced Installed new 5kV cables and cable tray 39

40 Reliability Upgrades following the Arc Flash Project Rebuild of plant ground grid Replaced 5kV cables feeding substations (AFE) Annual testing of all 5kV synchronous motors Substation transformer testing Annual main substation (138kV/5kV) testing 40

41 Recommendations - Lessons Learned Completion of an arc flash assessment delivers a look under the hood for the entire plant site. Take action with plant upgrades based on a defined priority list Operational reliability can be enhanced as an unexpected benefit following implementation of safety based upgrades This plant went from middle of the road productivity to top of the pack for 14 North American plants Although manual racking of medium-voltage circuit breakers and contactors from energized bus was once commonplace, the known risk in this procedure has rendered the activity obsolete Current standards/regulations for lockout/try/tagout need to be reviewed and updated to align with the latest technologies Remote isolation systems are operational today and have proven to reduce workplace safety risks and also enhance productivity 41

42 Questions? Two Recent Case Studies in the Mining Industry Remote Isolation Arc Flash Remediation David B. Durocher Senior Member, IEEE Global Industry Manager, Mining Eaton Corporation SW Kinsman Rd Wilsonville, OR USA