Customer presentation, PG Service, BU Motors and Generators ABB LEAP Stator Winding-Condition & Lifetime assessment

Transcription

1 Customer presentation, PG Service, BU Motors and Generators ABB LEAP Stator Winding-Condition & Lifetime assessment

2 ABB LEAP Overview ABB LEAP - Benefits for customer Motivation to perform LEAP Failures statistic Consequences of stator failure Basic LEAP Theory LEAP levels and measurements LEAP versus traditional measurements LEAP report LEAP case studies May 13, 2013 Slide 2

3 ABB LEAP Introduction ABB LEAP (Life Expectancy Analysis Program) is unique diagnostic tools for motors and generators which assesses the condition of the stator winding insulation, evaluates the remaining life of the stator winding insulation Site measurements are performed by trained personnel in the ABB Service Center network and the data analyzed at the ABB LEAP Center of Excellence at Mumbai Service is performed by Local ABB Service Providers Benefits for customers ABB LEAP creates optimized maintenance plans that helps our customers to minimize unplanned downtime extend motors and generators lifetime boost return on investment reduce operating risks May 13, 2013 Slide 3

4 Failure Statistics IEEE and EPRI 70% 60% 61% 50% 40% 30% 37% 33% 20% 10% 8% 8% 6% 5% 5% 2% 4% 3% 7% 11% 10% 0% May 13, 2013 Slide 4 Failures observed in motor during normal operating condition Failure identified in motor when carrying out activities such as: Preventive Maintenance Condition Monitoring

5 Stator Failure Consequences. What is the time for repair? What are the costs involved in a complete stator replacement or rewinding? What are the losses related to production due the stator failure Downtime cost May 13, 2013 Slide 5

6 Factors influencing stator winding life Age, voltage, speed, operation Total Failure Rate Vs Age %wdg. Failure Rate % Age (Years) % Pole Number Series1 %wdg Failure Rate Wdg Failure Rate % Series % or less More than 1 Voltage(Volts) No of Starts/day May 13, 2013 Slide 6

7 Stress, strength Basis of LEAP Stress & Strength vs Time Strength Premature Failure Transients Failure Stress Residual Life Time May 13, 2013 Slide 7

8 Life Expectancy Analysis The Benefits Strength Condition assessment and taking suitable actions at this point. Transients Adv. 1: No Premature Failure Stress Failure Residual Life Adv. 2: Increase in Life May 13, 2013 Slide 8

9 LEAP The levels May 13, 2013 Slide 9

10 LEAP Measurements General Information Can be applied on Machines from any Manufacturer Time for data collection approximately 4 hours with machine stopped (off line tests) Not necessary to open covers / machine for data collection Only need access to the terminal boxes Non destructive tests May 13, 2013 Slide 11

11 LEAP Measurements Standard Package DC measurements gives more information on the surface of the insulation AC measurements gives more information on the volume of insulation DC Measurements PDCA-Polarization Depolarization current analysis AC Measurements Tan delta(tan δ) /Capacitance analysis Partial discharge (PD) NLIBA-Non linear insulation behavior analysis May 13, 2013 Slide 12

12 LEAP measurements Salient points DC measurements: Conventional IR,PI values may be satisfactory even for highly contaminated windings AC measurements: Conventional measurement interpretation is based on trend DC Measurement By measuring leakage and absorption current, PDCA test helps quantify and identify location of charge storage within the machine Identifies contamination even when IR, PI values are acceptable Determines state of winding insulation, ageing, contamination etc AC Measurement Confirm the results from DC Measurements Assess the condition of Corona protection shield Determine the extent of delamination or void content in terms of a percentage of discharging Air Volume to Insulation Volume Assess condition of the Stress Grading system at slot ends Trend Ageing effects Q3 Q1, Q2 May 13, 2013 Slide 13

13 LEAP Vs Traditional measurement How is it different? Traditional measurement looks at values such as IR, PI, Tan δ, whereas LEAP looks from point of strength aspects of insulation Trend of data required in traditional analysis. With LEAP finger print can be established with one set measurement 65-72% of failures are related to Thermal (aging) and Ambient reasons which may not be detected by measurements that rely only on partial discharges. ABB s measurements and analysis focuses also on detection non-partial discharge related problems Analysis software is UNIQUE and parameters derived from analysis can be utilized in Life Expectancy Calculations Can be related to time and shall be integrated into the Maintenance Plan May 13, 2013 Slide 14

14 LEAP Reports Provides condition assessment of stator winding Helps make short term maintenance plan Provides remaining lifetime of stator winding Helps make long term maintenance plan Provides recommendation What maintenance needs to be done When maintenance needs to be done What winding areas to attend When to perform rewinding or buy new stator May 13, 2013 Slide 15

15 LEAP Benefits to customer Compliments maintenance planning of electrical machines Helps extend life of machine by suggesting correct maintenance at appropriate time leading to better return of investment Facilitates decision making in short and long run Provides lifetime inputs to make realistic calculation of lifetime costs May 13, 2013 Slide 16

16 LEAP Cases Contamination 11 MW, 11KV, 1500 rpm Synchronous motor Purpose of test: The motor was in operation for 69,000 hours with no outage. LEAP Standard carried out to determine the need for L3 or Level 4 Inspection. On-line pd alarm had appeared Results PDCA test: IR Meg ohm PI (Limits) Q1(%) 9.63 (<7%) Q2 (%) (<10%) Q3 (%) (< 20%) Key findings LEAP Standard indicated presence of oil/carbonized contaminants predominantly on the overhangs Recommendation Benefits Open the end covers and clean end windings. No immediate need of overhaul with rotor removal Optimized maintenance planning May 13, 2013 Slide 17

17 LEAP Cases Insulation wear 725 KW, 6.6KV, 990 rpm Sector Petrochemical Industry Purpose of test: Routine shutdown checks Results Performed LEAP Standard Evidence of Slot PD recorded from PD pattern Key findings Substantial erosion of corona protection field indicated Recommendation Customer advised to open the machine and re-impregnate the windings with resin Benefits Life extension May 13, 2013 Slide 18

18 Stress/Tensile Strength (MPa) Equivalent Operating Hours ( x 1000 ) LEAP Cases Lifetime optimization Present Equivalent Operating Hours LIFE ESTIMATION Remaining Life ( eq. hrs) Equivalent Operating Hours at Intersecting Points Stress Developed (9240 psi or MPa) MW, 23KV, 2 pole Generator Sector Power Plant Purpose of test: Results To validate health condition since machine is in operation for 20 years Performed LEAP Premium Tests done: LEAP Standard Wedge deflection Bump test Key findings Looseness in wedges and end windings Recommendation Benefits Customer advised to do re-wedging and implement new tie ups between coil and support structure. Life extension May 13, 2013 Slide 19

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