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October 04

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Operations/Performance

Had I written this at the beginning of November, my tone would've been unquestionably different. As I procrastinated…we're now at the end of another long outage…in a rather discouraging game of discovery and repair. We have all worked hard during this month and I would like to warmly thank each of you for a super job, well done. It's been a month of adversity, testing, expectation, and disappointment. It isn't over yet…but I know we'll come out of this period with a true sense of accomplishment. After all, our best thinking is done when we're confronted with a problem. 

October was another extraordinary month, giving us records on Block 2 output and capacity factor. Capacity Factor is the percentage of generation that was actually produced compared to what “could have” been produced. Each month this number is adjusted for ambient conditions so it essentially becomes a rolling average for the year. Both blocks are in the 80's (%) capacity factor for 2004, making it a number our neighbors would envious of. The stats below say it all.

October 2004

  • Production= 633,650 MWhr
  • Block 2 “record month”, generating 343,041 MWhr at a Capacity Factor of 97.1 %.
  • 2004 total generation (as of October): 5,855,241 MWhr
  • October Equivalent Availability:
    • Block 1: 92.3%
    • Block 2: 100.0%
  • Q3 Combined Average Equivalent Availability= 99.4%
    (2004 max target for Q3 is 95%)
  • Average Net Heat Rate: 7081 Btu/kWhr
  • Technical Availability: 100.01%
  • 2004 Technical Availability: 100.04%
  • Combined Q1-Q2 Equivalent Availability= 90.0%
    ( 2004 max target for Q1-Q2-Q4 is 89.7% )

The October 2004 report can be found on the Mesquite webpage ( http://www.mesquitepower.com/business/ppt/Oct-04.ppt).

Shift Operations

500kV Transformers:

I know if I were reading this, I'd want to hear what's going on with the 500 kV transformers and why we can't run the plant. I assure you we could be in much worse shape than we are, having dodged the proverbial bullet once again. Regardless, it's not the best of circumstances and I'll briefly fill you in where we are and also sketch our recovery schedule:

On November 4th, we re-energized the 500 kV autotransformers following repairs on the 230 kV L1 breaker along with routine, non-intrusive testing of the 500 kV autotransformers (no…we can't blame this one on Steve P). Later that day the gas analyzer on the B-phase transformer detected a high gas level on this unit. At some point later that week, the C-phase transformer also detected a high gas reading. The oil was sampled and sent to a lab whereon last Monday (11/22) the results were returned to us showing excessively high hydrogen and combustible gas levels in these two transformers. A decision was quickly made to shutdown the facility and investigate the problem. We were at the time, in a very critical, possibly catastrophic situation.

Gassing of the oil in any transformer can be an indication of arcing between the grounded parts of the unit and the energized portion (coils or leads). Destructive conditions can be created from this anomaly as the transformer oil breaks down into its elemental components. Our Fuji units have onboard gas detectors that detect any changes (in ppm levels) in gas content and these initiated soon after re-energization on the 4 th .  To validate the meters, you would conduct a dissolved gas analysis (referred to as DGA) to determine the specific concentrations of certain gases in the oil such as oxygen, carbon monoxide, carbon dioxide, hydrogen, methane, ethane, ethylene and acetylene. Depending on the concentrations of these gases, you can diagnose certain operational problems with the transformer, which may be associated with a change in a physical or chemical property of the insulating oil. An example would be high levels of carbon monoxide relative to the other gases may indicate thermal breakdown of cellulose paper, while high hydrogen, in conjunction with methane may indicate a corona discharge within the transformer. In our case, we had excessive levels of hydrogen and acetylene, combined with high levels of carbon. Since carbon monoxide levels were relatively low, our indications led us to look for a metal-metal arc, not a core insulation failure.

That was the good news. Our relay and transformer testing company, Hampton Tedder, was able to quickly locate the fault at a failed insulation section between the core centering tie bolts and the beam that holds load force on the transformer coils (see attached file). This failure caused an arc point that led to the creation of acetylene and hydrogen gas in the transformer oil, ultimately detected by our instrumentation and subsequent oil analysis. We were exceptionally lucky to catch this when we did, as continued operation under these conditions could have spelled nothing less than “doom” for Mesquite Power.

As of today, all of the 500 kV transformers have been inspected and an evaluation of their condition has been made. Fuji Electric has sent two of their design Engineers to assist us and they'll stay throughout the repair process and re-energization. The A-phase and the spare transformers both check out in good condition and to improve recovery time, the spare will be placed in service instead of the C-phase. Insulation of the tie-bolts on B-phase and C-phase will require replacement and these transformers will need to be thoroughly cleaned and the oil satisfactorily purified once repairs are done. The repairs will be performed over the next couple days and critical path will become cleaning of the oil in B-phase throughout the rest of the week. If all goes well, plan on backfeed by Friday or Saturday and then moving forward with restoring the facility.

In order of appearance:

We'll have a group of photographers onsite today through Wednesday to shoot Mesquite for the Sempra Energy annual report. Wear your best Mesquite shirts and smiles because they also want to take your photo. Our 2004 Community Event will take place on Friday, December 10 th with Habitat for Humanity, building a house in Phoenix (19 th Ave & Southern, Villas Esperanza). This is a ‘sponsored' event for everyone who can attend. Also, our annual Christmas party will be the following day, December 11 th at Jillian's in Scottsdale .

Congratulations to Shift 1 for their winning the coveted Operational Excellence award in October. A heated battle goes on for the annual prize though November's numbers will not be generated due to the outage. December is all you have left.

Some people probably felt a bit older this month, having gone by their 2 nd anniversary with Mesquite Power. Along with myself, I congratulate Jay, Mike Cox, John, Dave, Steve P, Steve K, Joe, Henry, Kevin, Ed, Troy, Jeff, Ray, Pat, Bob, and Michael Paul (did I miss anyone?) for their continued devotion and perseverance. Hard to believe so much time has gone by…sure was a lot of fun.

ADOSH paid us a visit last Tuesday to kick-off our SHARP process. Other than a few administration objectives, it looks very good for us to earn this certification and important recognition for our facility.

Next Month

There are two significant operational issues that will be addressed in December, one being STG4 restart and the other as additional pretreatment changes. Realistically, we can expect the restart of STG4 will go smoothly with only a few opportunities to correct field issues. However…anything can happen after such a major evolution so plan for the worst…hope for the best.

You'll notice a large stainless tank set-up at pretreatment near the floc-tube assembly. On restart, we'll be injecting a hydrated (lime/magnesium hydroxide) slurry solution from this point and utilizing a sort of “modified cold lime” program in the clarifiers. We want to accomplish two things here, 1.) provide a stabilized process for chemical injection and 2.) obtain moderate results of silica removal that mirror cold lime softening. Following a period of stabilized chemical feed, we'll reintroduce the Purefloc solution in the raw water and continue with this program. Additionally, we've asked GE-Betz to proceed with a new inhibitor treatment that will allow higher levels of soluble silica in our cooling water. This new product introduction will require a monitoring and validation period and will only be (initially) conducted on one cooling tower.

I hope everyone had a safe and Happy Thanksgiving, cheerfully anticipating the holiday season ahead. These are the busiest of times for us: facility recovery, end of year close-outs, and tying up loose ends on everything from warranty to regulatory reporting. Amidst all that, we have a power plant to run. We'll get through it though and start out 2005 looking pretty.

Best Regards,

Merritt

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