Monitoring of Electrical Equipment Failure Indicators and Alarming

Transcription

1 Past, Present and Future Maintenance Practices: Monitoring of Electrical Equipment Failure Indicators and Alarming Author: Gabe Paoletti, P.E. Eaton Corporation Senior Member, IEEE Cell #

2 PAST: TIME BASED MAINTENANCE Past maintenance practices were based on original equipment manufacturers or industry standard guidelines. While some of these guidelines were based on the number of equipment operations, the majority resulted in a time-based maintenance program. 2

3 PAST: TIME BASED MAINTENANCE EXAMPLE TIME-BASED PREVENTATIVE MAINTENANCE (Minimum) Equipment Type Mechanical Operation Check Visual Inspection Energized Infrared Inspection and/or Oil Testing Outage Preventive Main.& Testing Cables Terminations & Connections 1 year 1 year 3 year Liquid filled transformers 1 year 1 year 3 years Dry type transformers 1 year 1 year 3 years Metal-clad switchgear Monthly 1 year 3 years MV Circuit Breakers 1 year 1 year 1 year 3 years Buses and Bus ducts 1 year 1 year 3 years Protective relays 1 year 1 year Automatic Transfer Equipment 1 year 6 months 1 year 3 years Low Voltage Equipment 1 year 1 year 3 years Dry type transformers 1 year 1 year 3 years Switchgear 6 months 1 year 3 years LV Circuit Breakers 1 year 1 year 1 year 3 years Panel boards 1 year 1 year 3 years Direct-Current Systems: Batteries 3 months 1 year 1 year Direct-Current Systems: Chargers 3 months 1 year 6 months Electrical Safety Equipment Per OSHA Per OSHA Per OSHA Ground-Fault Protection Systems 1 year Motor Control Centers 1 year 1 year 1 year 3 years Rotating Machinery: AC Motors 1 year 1 year 1 year 1 year Rotating Motors & Generators 1 year 1 year 1 year 1 year Metering 1 year 1 year 3 years 3 Outdoor Bus Structures 1 year 1 year 3 years

4 PAST: TIME BASED MAINTENANCE ISSUES Circuit breaker guidelines would recommend detailed inspections following a fault interruption, but when a fault occurs most of the resources are diverted to identifying and correcting the down steam fault, and restoring power as soon as possible, therefore the circuit breaker was usually neglected Past Time-Based Maintenance is VERY DIFFICULT to properly implement 4

5 PRESENT: MAINTENANCE NEEDS Present maintenance has been driven by a reduction in maintenance budgets, while the need for electrical uptime has become even more critical. Resources reduced, expectations the same When the equipment is available for maintenance, there is no funding to perform the maintenance, and when the funding is available, the equipment is not accessible to perform the required maintenance. 5

6 PRESENT: MAINTENANCE ISSUES 100% 80% 60% 40% 20% 100% 0% % 60% 40% 20% Resources Resources Expectations Uptime Catastrophic Risk Expectations Uptime Catastrophic Risk 0% PAST Reduced Resources Uptime may be reduced Potential Failure Risks increase Management Expectations expect continuous Uptime FUTURE Unique Solutions Technology 6

7 PRESENT: NEW MAINTENANCE APPROACHES Review past maintenance records and observe equipment operating conditions and determine the level of maintenance required based on this historical data. Maintenance work scopes would also be adapted to Full-Maintenance which involved the traditional maintenance practices and a lesser level of maintenance, referred to as Operational Maintenance. 7

8 PRESENT: NEW MAINTENANCE APPROACHES The equipment would be rated and ranked based on the past maintenance records and ongoing visual inspections. Low-resistance (Doctor) measurement across a circuit breaker contacts Insulation resistance of electrical distribution equipment, as well as gas-in-oil testing results for transformers. 8

9 PRESENT: FULL VS. OPERATIONAL MAINT. LV BREAKERS LV BREAKERS FULL MAINTENANCE OPERATIONAL MAINTENANCE INSPECT AND OPERATE INSPECT AND OPERATE CHECK RACKING CHECK RACKING LUBRICATE LUBRICATE MEGGER (INS RESISTANCE) MEGGER (INS RESISTANCE) HIGH-CURRENT TESTING - ALL PHASES LOW-CURRENT TESTING - ONE PHASE CLEAN CONTACT RESISTANCE TESTING INSPECT ARC CHUTES, CONTACTS CHECK AUXILIARY DEVICES CHECK MECHANISM MAN-HOURS MAN-HOURS Savings exceed 30% during a typical scheduled outage. In a case study involving 390 low voltage circuit breakers, 52.8% of the circuit breakers were candidates for a reduced scope of maintenance (Operational Maintenance).

10 FUTURE: MAINTENANCE REQUIREMENTS End-User Needs Fewer Outages Possible Lower Capital & Maintenance Budgets Higher reliability required Unknowns of the current state of the electrical system My current budget is limited Let me know that I must do maintenance and when. 10 Let me know that I must investigate a potential problem now.

11 FUTURE: CONTINUOUS MONITORING Continuous monitoring of critical failure modes, while performing this monitoring in a cost effective manner What to monitor? (IEEE Gold Book) 11 Parameter IEEE Standard Failure Contributing Causes App E, Table XVIII, (Ins & Bare Bus Gear) IEEE Failure Causes Humidity 23.1% Dust Sensors 14.9% Temperature 9.0% Relay Outputs 7.2% Motion 4.9% Water 3.6% Smoke 3.4% Total 66.1% Gold Book data from 1970 s on old electrical equipment.

12 IEEE Failure Data (e.g. Switchgear Bus) Switchgear Bus Failure Contributing Causes (%) From IEEE Std Ins. Bare Pro-Rated Monitoring Options Appendix E - Table XVIII Bus Bus Total to 100% Expected Application 5/15kv 480volt Thermocycling 6.6% 6.6% 3.4% Temperature 3.4% Mechanical Structure Failure 3.0% 8.0% 11.0% 5.6% Mechanical Damage From Foreign Source 6.6% 6.6% 3.4% Motion 3.4% Shorting by Tools or Metal Objects 0.0% 15.0% 15.0% 7.7% Shorting by Snakes, Birds, Rodents, etc. 3.0% 3.0% 1.5% Motion 1.5% Malfunction of Protective Relays 10.0% 4.0% 14.0% 7.2% Relay Trouble Contacts 7.2% Improper Setting of Protective Device 0.0% 4.0% 4.0% 2.1% Above Normal Ambient Temperature 3.0% 3.0% 1.5% Temperature 1.5% Exposure to Chemical or Solvents 3.0% 15.0% 18.0% 9.2% Exposure to Moisture 30.0% 15.0% 45.0% 23.1% Humidity 23.1% Exposure to Dust or Other Contaminants 10.0% 19.0% 29.0% 14.9% Special Airborne Sensors 14.9% Exposure to Non-Electrical Fire or Burning 6.6% 6.6% 3.4% Smoke 3.4% Obstruction of Ventilation 0.0% 8.0% 8.0% 4.1% Temperature 4.1% Normal Deterioration from Age 10.0% 4.0% 14.0% 7.2% (Temp is some benefit) Severe Weather Condition 3.0% 4.0% 7.0% 3.6% Humidity/Temperature/Wate 3.6% Testing Error 0.0% 4.0% 4.0% 2.1% Total 94.8% 100.0% 194.8% 100.0% 66.1% Other Relay Outputs; Surges, Sags, High Loads 12 Patent Pending

13 IEEE Failure Data (e.g. Switchgear Bus) Switchgear Bus Failure Contributing Causes (%) From IEEE Std Ins. Bare Pro-Rated Monitoring Options Appendix E - Table XVIII Bus Bus Total to 100% Expected Application 5/15kv 480volt Thermocycling 6.6% 6.6% 3.4% Temperature 3.4% Mechanical Structure Failure 3.0% 8.0% 11.0% 5.6% Mechanical Damage From Foreign Source 6.6% 6.6% 3.4% Motion 3.4% Shorting by Tools or Metal Objects 0.0% 15.0% 15.0% 7.7% Shorting by Snakes, Birds, Rodents, etc. 3.0% 3.0% 1.5% Motion 1.5% Malfunction of Protective Relays 10.0% 4.0% 14.0% 7.2% Relay Trouble Contacts 7.2% Improper Setting of Protective Device 0.0% 4.0% 4.0% 2.1% Above Normal Ambient Temperature 3.0% 3.0% 1.5% Temperature 1.5% Exposure to Chemical or Solvents 3.0% 15.0% 18.0% 9.2% Exposure to Moisture 30.0% 15.0% 45.0% 23.1% Humidity 23.1% Exposure to Dust or Other Contaminants 10.0% 19.0% 29.0% 14.9% Special Airborne Sensors 14.9% Exposure to Non-Electrical Fire or Burning 6.6% 6.6% 3.4% Smoke 3.4% Obstruction of Ventilation 0.0% 8.0% 8.0% 4.1% Temperature 4.1% Normal Deterioration from Age 10.0% 4.0% 14.0% 7.2% (Temp is some benefit) Severe Weather Condition 3.0% 4.0% 7.0% 3.6% Humidity/Temperature/Wate 3.6% Testing Error 0.0% 4.0% 4.0% 2.1% Total 94.8% 100.0% 194.8% 100.0% 66.1% Other Relay Outputs; Surges, Sags, High Loads 13 Moisture & Dust: 38% Patent Pending

14 FUTURE: FAILURE CONTRIBUTING CAUSES IEEE Standard Failure Contributing Causes App E, Table XVIII, (Ins & Bare Bus Gear) Parameter IEEE Failure Causes IEEE Failure Causes Failure Contributing Causes End-User Feedback (April, '08) Humidity 23.1% Humidity (LV), Discharges (MV) Humidity (LV), Discharges (MV) Dust Sensors 14.9% 26.7% 24.9% Temperature 9.0% Dust, Smoke Dust, Smoke Relay Outputs 7.2% 18.3% 16.6% Motion 4.9% Heat, Fire Heat, Fire Water 3.6% 9.0% 12.5% Smoke 3.4% Total Total Total 66.1% 54.0% 54.0% 14 IEEE data was then grouped into sub-sets in three categories: Humidity/Water-Discharges, Dust-Smoke and Heat-Fire and correlated against end-user surveys which were conducted at random IEEE regional meetings

15 FUTURE: FAILURE CONTRIBUTING CAUSES IEEE Standard Failure Contributing Causes App E, Table XVIII, (Ins & Bare Bus Gear) Parameter IEEE Failure Causes IEEE Failure Causes Failure Contributing Causes End-User Feedback (April, '08) Humidity 23.1% Humidity (LV), Discharges (MV) Humidity (LV), Discharges (MV) Dust Sensors 14.9% 26.7% 24.9% Temperature 9.0% Dust, Smoke Dust, Smoke Relay Outputs 7.2% 18.3% 16.6% Motion 4.9% Heat, Fire Heat, Fire Water 3.6% 9.0% 12.5% Smoke 3.4% Total Total Total 66.1% 54.0% 54.0% 15 IEEE data was then grouped into sub-sets in three categories: Humidity/Water-Discharges, Dust-Smoke and Heat-Fire and correlated against end-user surveys which were conducted at random IEEE regional meetings

16 FUTURE: MONITORING REQUIREMENTS Approximately 50% of potential failure contributing causes of electrical distribution equipment can be monitored, trended and alarmed to provide the desired future maintenance mode of operation. Humidity and the presence of water Partial Discharges (MV Equipment) Dust Trending and Smoke Detection Temperature trending of cubicles, bus-duct, critical cable joints and/or bus connections Bus / Cable Connection Point-Temperature sensors Load Current, Heater and Fan Circuit Currents Intrusion or motion 16 Additional Options for rotating apparatus: Vibration of rotating apparatus Exert herm IR sensors

17 FUTURE: MAINTENANCE REQUIREMENTS Internal Copper Bus Internal Void Bus Insulating Sleeve Internal Void Cubicle Barrier MV Partial Discharge Detection in MV Gear (13.8 / 34.5kv+) Partial discharges emit high-frequency radiation and the application of specifically designed sensors, with filtering and data analysis equipment allows for the continuous monitoring of these partial discharges which will lead to eventual equipment failure 17

18 FUTURE: MONITORING REQUIREMENTS Partial discharge detection and temperature sensors, when combined with sensing options such as humidity, floor water, dust, smoke, load/heater/fan currents, cubicle or bus-duct temperatures provides a robust predictive monitoring package for both low voltage and medium voltage equipment. By adding available vibration sensors to the above, this is adapted to rotating equipment. Patented Algorithms, based on historical and designedbased operating conditions, which will alarm when a parameter is considered out of the normal operating range and provide maintenance recommendations. 18

19 FUTURE: SAFETY & SMART GRID FACTORS Safety: Thermographic surveys require direct viewing of energized connections, requiring removal of panels and exposing of energized equipment. With the Arc-Flash protection requirements, difficult to safely implement. One safety solution: infra-red viewing windows Surveys must still be scheduled and therefore do not provide continuous monitoring Solution is remote continuous cubicle temperatures trending with algorithms Smart Grid: Being notified of a potential pending failure, before it occurs, provides us with a smarter grid. 19

20 Characteristics of Air: With increased temperature - air changes from an insulator to a conductor - Flashover becomes self-conducting Ionized Air Ref: W. Rieder, Circuit Breakers: Physical and Engineering Problems, IEEE Spectrum, July

21 PREVENTABLE FAILURE CASE STUDIES 21 Monitor Humidity, PD, Dust & Contamination (Moisture) Life Ext: Vacuum Replacements ANSI Tested Monitor Cubicle and/or Point Temperatures (Overheated finger cluster) Monitor Cubicle Humidity & Heater Current (Heater Failure)

22 PREVENTABLE FAILURE CASE STUDIES 22 Monitor Floor Water (Overhead water & upstream breaker failure Life Ext: ArcFlash Reduction Switch, Arc Res MCC s Monitor Cubicle and/or Point Temperatures (Improper Maintenance) Monitor Cubicle Temperature (Finger Cluster Failure)

23 FUTURE: MONITORING CASE STUDY Case Study: Monitoring of the above parameters would have warned of a pending major equipment failure due to severe weather conditions and the subject equipment could have been de-energized and isolated from the electrical grid. Since the monitored environmental parameters where not available to the remote operator, the equipment was re-energized in an attempt to clear an anticipated minor fault and resulted in the completed melt-down of the medium voltage circuit breaker and the associated enclosure. 23

24 Diagnostic Remote Monitoring Automatic Report Example Red Light = Alarm Yellow Light = Inspect soon Green Light = Good

25 Customized Automatic Reporting Red Light = Alarm Yellow Light = Inspect soon Green Light = Good

26 Temperature Sensor Alarm Level: Text Message Voice Message Text Message: High Temp Cub XX Bus B

27 Alarms - Blogs Global Coverage Iridium Satellites

28 SUMMARY The future of maintenance is here today Economic swings are preventing past maintenance practices Review available IEEE failure contributing causes Combined with recent end-user surveyed data Identify parameters to be continuous monitored, trended and alarmed Application of new technologies (PD, temperature, algorithms) IT-independent or integrated into a facility monitoring and alarming Smart-grid systems that can self-predict a pending failure and also provide for ongoing maintenance recommendations Technological solutions exist today to support this future maintenance mode. Tell me when I need to do maintenance & what maintenance to do. Tell me that I have a problem now and what I should do about it. 28

29 Questions? Past, Present and Future Maintenance Practices: Monitoring of Electrical Equipment Failure Indicators and Alarming Author: Gabe Paoletti, P.E. Eaton Corporation Senior Member, IEEE Cell #