CITY COUNCIL AGENDA ITEM
ACTION REQUESTED:
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Approve the award of Bid 25-074, Field Services for Tollway Substation Transformers, to Reinhausen Manufacturing and Transfluid Services, Inc. for an amount not to exceed $597,079
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DEPARTMENT: Electric Utility
SUBMITTED BY: Brian Groth
BOARD/COMMISSION REVIEW:
N/A
BACKGROUND:
The City of Naperville Electric Utility (Utility) is responsible for maintaining electric service to approximately 63,000 residential and commercial customers. A key component of the 16 electrical substations owned by the Utility, and used to distribute electricity around the city, are transformers that step the 138kV transmission voltage down to lower voltages. At its Tollway Substation, the Utility owns a three-winding transformer referred to as 30XA. This transformer was built in 1971 and steps down voltage from 138kV to 34.5kV and 12.47kV, respectively.
In September 2024, the transformer tripped offline, the Utility attempted to re-energize the transformer, but it was not successful. Subsequent laboratory analysis of the oil showed an alarming increase in combustible gases, including acetylene, suggesting internal arcing within the tank of the transformer. City crews performed additional electrical testing and discovered evidence of a fatal secondary winding to ground failure on one of the 12kV windings. The Utility hired a consultant to verify the test results and enter the transformer to perform a visual inspection. The consultant confirmed catastrophic physical damage within the transformer.
After confirming that the transformer had catastrophically failed, City staff evaluated options and developed multiple bid packages to obtain the best combination of pricing and lead times for the replacement/refurbishment of 30XA. Ultimately staff recommended, and the Council concurred with, awarding Bid 25-029 in June of 2025 to procure a replacement for the Utility's system spare transformer.
Due to redundancy in design of the sy...
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