General

Keeping OPPD’s balancing stations in top shape

OPPD relies on its balancing stations – also known as peaking stations – to help produce power when the region needs it most. Those same stations have to be cared for much like the larger base-load stations that produce the bulk of the power used by customers.

This spring, OPPD’s Cass County Station was placed on an extended planned maintenance outage. Such outages are done so inspections, parts replacement and overall upkeep can be done.  Think of it like having your vehicle or furnace serviced, but on a much grander scale.

“It was a successful outage,” said Greg Schroeder, supervisor of Maintenance Services at OPPD. “There were no injuries, which is always our highest priority. Everyone had a good, questioning attitude, and that’s what we want to see.”

Extended maintenance outage

The outage spanned from March 21 to May 24, a long haul for the workers and contractors involved, especially given the always unpredictable Nebraska weather.

“There was a stretch where we worked for two weeks straight, 12-hour days, no days off,” Schroeder said. “If it wasn’t raining, it was snowing or icing on us. We had a few times where the deck froze over. There were a few high wind days where we had to collapse the crane so it wouldn’t blow over.”

Schroeder said he was pleased with how well the OPPD employees worked with the Siemens workers. All turbine parts that were replaced came from Siemens. The field techs from the company were there to help OPPD employees with that process.

“The Siemens techs were great advocates and worked side by side with our machinists and steams fitters and were very willing to share their knowledge, which was great to see and which helps our people going forward.”

Planning and scheduling

Spring and fall are the preferred times for planned outages on generating stations. At those times, there is a lower load demand around the region.

So the outage at Cass County wasn’t the only one going on at the time. When the Cass outage started, Nebraska City Unit 1 was in a three-week planned outage and North Omaha Station Unit 5 was also in a three-week planned outage. Another maintenance project and a repair project were also happening at the time.

Schroeder credits the planning and scheduling groups at OPPD for ensuring that were no logistical problems.

Those groups “kept everyone moving forward,” he said.

Safety first

Though not nearly as high up the priority list as some of the repairs and parts placements done, there was also a potential safety hazard was also quickly addressed. The walking paths around the Cass County Station contained large pieces of rock and gravel. Such a hazard could mean a big delay if one of the crafts people were to turn an ankle due to the uneven footing, and that could throw a planned maintenance outage off schedule.

“That might seem like a small thing, but when you are in critical path on an outage, little things like that can make a big difference,” he said. “We want to do everything we can to make this as safe as possible. It goes back to everyone really being in tune and watching out for each other.”

Some Cass County maintenance outage facts and figures:

• Replaced both inlet and exhaust bearings and shipped the used ones back to Siemens.
• Opened both ends of the generator and did extensive testing, including adding blocking to the generator windings.
• Removed all four upper and lower diaphragms and replaced with new veins.
• Removed and replaced all four rows of turbine blades.
• With all the hours worked and several crane lifts, not a single employee was injured and there were no vehicle incidents.