PUC authorizes needed equipment purchases
NEW ULM — Switchgear, water line, feed water pump, and backup potential transformer were all part of a list of equipment purchases authorized by the New Ulm Public Utilities Commission.
Several utility projects are currently underway or in the early planning stages. The PUC needed to authorize purchases to keep repairs and replacements on schedule.
The highest cost item was the Cooling Tower Motor Control Center replacement switchgear equipment. The commissioners authorized accepting a $208,100 bid for the replacement equipment.
The PUC previously authorized the replacement of this equipment in January. This equipment was scheduled to be replaced for years. Most of this equipment was installed in 1965. The switchgear equipment located inside the cooling tower has exceeded its useful life.
In addition to replacing the switchgear, public utilities want to relocate it. The switchgear is currently located inside the cooling tower and the damp atmosphere has caused corrosion. The replacement project calls for the creation of a separate enclosure for the replacement.
Utility Engineer Dan Pirsig said this replacement was originally budgeted for 2024 as materials were not expected to be delivered until late into the text year. The lead time is estimated at 55 weeks, meaning the project likely will not be complete until 2025.
The overhaul of the New Ulm power plant’s #4 generator turbine began in August. For insurance purposes, an overhaul of the turbine is required every 10 years or 50,000 hours. Manderfeld said this would be an eight to ten-week completion.
In related news, an emergency repair was needed to replace a cooling water line to the #4 generator turbine. A leak in the 24-inch cooling water line was discovered when putting the #4 generator online as part of a test for Midcontinent Independent System Operator (MISO) that was required by Aug. 31. MISO periodically requires tests of power generations. The feedline was needed quickly to complete the test but was also required as part of the scheduled overhaul of the turbine.
The emergency repair was conducted by Southern Minnesota High-Pressure Piping for $57,048.53.
The PUC also approved a quote to rebuild the feed water pump inside the New Ulm Power Plant. Two bids for the project were received, and the PUC accepted the low bid from Engineered Pump Service for $31,360.
Manderfeld said there could be additional costs with the project once the current feed water pump is opened. The impeller blades inside the pump might need to be replaced, but NUPU will not know if additional repairs are needed until the project starts.
The purchase of a backup Potential Transformer (PT) was approved by the commissions for $7,287.
The PT is typically located on the structural steel at a substation.
Utility Engineer Dan Pirsig explained that last spring there was a leak at The North Substation. The Utility Department used a spare PT in stock to replace and keep the substation in service. However, now the utilities are in need of another spare PT for backup purposes.
With ongoing supply chain issues, Pirsig wanted to place the order for the spare PT now to ensure the substations would remain running in an emergency. It was estimated to take 15 weeks for the spare parts to arrive.