Trials and Tribulations of Transformers and Turbines at a Pesky Peaking Power Plant

Transcription

1 Eugene Water & Electric Board Trials and Tribulations of Transformers and Turbines at a Pesky Peaking Power Plant NWHA Technical Seminar May 7 th, 2015

2 Carmen- Smith Diversion Smith Dam Storage Trail Bridge Dam Re-regulation Plant Peaking-Carmen Plant

3 Seasonal Reserve Margin

4 Carmen Peaking Service

5 HydroAMP Condition Assessments Power Train

6 90-Percent Fish Passage Design!

7 Electric Utility Competitiveness Electric Bill Utility 1 Utility 2 Utility 3 Utility 4 Utility 5 20 Utility 6 0 EWEB Utility 1 Utility 2 Utility 3 Utility 4 Utility 5 Utility 6 EWEB Utility 8 Utility 8 7

8 Electric Long Term Financial Plan - Projected Debt Service Coverage Ratios 2.50 Debt Service Coverage Policy Target Coverage for Additional Bonds

9 Rate Increase Mitigation (March 2012 vs. December 2012) 21.5% March 2012 Projection Wholesale Market & Other Factors 8.5% Carmen 5.5% Mid-year layoffs and O&M cuts to mitigate market factors 4% May Rate Increase 4% Projected BPA November Projected November BPA 7.5% March 2012 Projection Redo of Carmen- Smith CIP (slower) Lower estimate of BPA increase Market & Other 2% Carmen 2% Projected November BPA 4% December 2012 Board Approved 9

10 CIP Adjustments & Deferrals 2014 Financial Impact $60,000,000 $50,000,000 $19.3MM Planned Reduction from August 2012 $40,000,000 Type 3, $21,648,000 $30,000,000 $20,000,000 Type 2, $7,670,987 Type 3, $8,222,000 Type 2, $5,300,000 $10,000,000 Type 1, $20,641,949 Type 1, $17,109,062 $0 Approved CIP August Proposed 2014

11 Life Cycle of a Dam from ADSO 2

12 HydroAMP Condition Assessments Power Train

13 Carmen Turbine Protection Efforts

14 Observations O&M Increasing maintenance Access Concerns (TSV) Mechanical Components

15 Observations Vibration Monitoring System Shaft Draft Tube Mechanical Components

16 Observations Operation of units Units and the associated equipment are over 50 years old Cycling: Unit 2 cycled twice as often as Unit 1 A lot of low load operation Mechanical Components

17 Making Sense of It All Guidelines for Damage Evaluation Relative Vibrations Literature Industry Best Practices Overall Conservative Mechanical Components

18 Goals Make lots of power and never fix anything again Reduce of risk of unscheduled outages Extend economic life (aka: avoiding major repairs) Mechanical Components

19 Solutions Work with on-site O&M staff Bring observations and conclusions to Traders (Remote Operators) Path Forward Operational Guidelines Continue Inspections/ Monitoring Fine tune plan with help from Traders and Operators T/G Overhaul with new runners in 2019,2020 Mechanical Components

20 Carmen Transformer 2 DGA Triggered Testing & Inspection

21 XFMR Specs 1963 GE 132.5kV:11.5kV 50MVA (T2) ~7,000 Gal Oil Tank Forced Oil/Air Cooled DGA Monitors installed in 2008

22 Event Timeline May 22: Online DGA monitor high rate-of-rise alarm. May 23: Monitor data shows gas trend increase. June 5: DGA Sample Sent to Lab June 23: 12 ppm of Acetylene! Second sent for rush processing. June 25: DGA sample returned same result unit de-energized. July 23: Decision to perform testing and inspection September 14: Testing and inspection started.

23 Carmen Transformer 2 DGA Trend ppm/day ppm/day (17.5x orig trend) ppm/day Monitor Commissioned Unknown Decrease 1010 Breaker Failure Event Power Outage/Unit shut off Test, Inspect, Filter Oil ppm/day

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28 Inspection and Testing Findings All as-found and as-left testing showed no issues (PF, IR/PI, Core Ground, Winding Resistance). Internal inspection on accessible and visible components showed no indications. All auxiliary components tested (CT/PT, HV/LV Bushings, Pumps, connections). Oil filtered to remove moisture and dissolved gases. Root cause of acetylene unknown. Decision to restore unit to service and monitor closely.

29 Carmen Transformer 2 DGA Trend (to present) ppm/day (2.6x original trend) Test, Inspect, Filter Oil

30 Post Inspection Monitoring Plan DGA Lab Samples gathered every 2 weeks to establish new trend After 2 months, TDCG trended up and 2 ppm of acetylene appeared Load limit put in place at 30MW to determine load dependency PPM decreased, acetylene dissipated after 2 months of load limit 250 TDCG PPM Load Limit Started 0 10/1/ /1/ /1/2014 1/1/2015 2/1/2015 3/1/2015 4/1/2015 5/1/2015

31 Summary Equipment is beyond useful life (stick a fork in it). Equipment condition must be monitored closely. Additional risks must be taken to allow for operation. Projects must be prioritized minimal resources and funding

32 Questions/Comments??? Are we alone? We are interested in other s similar experiences, tactics and projects. Speak now, or find one of us during a break.