Complex Projects: Upgrading Utility Interconnection Substations

Recently, one of IEA’s larger manufacturing customers negotiated an agreement with its utility supplier to replace the three substations powering its largest manufacturing facility and corporate headquarters. The existing substations were 1960s vintage and suffering from reliability problems and were also overloaded during peak summer weather months. The utility was also upgrading its distribution system from 34.5 KV to 69 KV.

The challenge: Two of the new utility substations could be constructed on property adjacent to the old substations. To complete the cutover from old to new construction, it was necessary to disconnect the old power connections, reconnect to the new utility substations then test everything without forcing the customer to experience an electrical outage.

The solution: IEA already owned a standby generation facility at the customer’s site consisting of ten 1,600 KW generators. IEA developed a plan that allowed all plant loads to be carried off a single utility feed while the changeover from the old utility feed to the new substation was completed. Because of phase shifts between the utility company substations, IEA operated its generation plant to accept load and then permit manual transfer of loads between substations.

IEA developed a detailed plan for this load transfer, which had never been attempted before in a manual mode. Checklists were created which instructed system operators exactly how to start all engines manually, synchronize manually, then transfer loads by operating breakers manually. Several variations were created because the cutover to the new substations took place in several steps.

The result: IEA coordinated multiple parties working cooperatively to complete the project in a successful manner.

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