Anne Arundel Substation aerial

Substation Transformer and Breaker Replacement

One of Delta’s recent projects was replacing the transformer and breaker for a substation that has been in service since the late 1920s or early 1930s. The failed 110/33 kV transformer was originally commissioned in 1970.

Service: Substation Construction

Location: Anne Arundel County, MD

Scope: Delta Utility Services installed an auto transformer (HV 110 kV; LV 34 kV) manufactured by Delta Star to replace an existing station transformer. Replacing this aging asset increases system reliability.

Delta also installed an R-MAG Vacuum Circuit Breaker (34 kV; 2000 A; 40 kA), manufactured by ABB, to replace the existing low side bus breaker. The R-MAG is based on magnetic actuation. Compared with traditional spring mechanisms, it is advantageous because it has fewer moving parts and is mechanically simpler.

Additionally, Delta replaced both the transformer oil retention pit and mother pit.

Safety: Adhering to established safety procedures, Delta had the whole area M-scoped and tested. We also used our hydro-excavator to dig safely and avoid hitting any of the underground utilities.

Quality Management: Delta proficiently navigated the challenges of this long-established substation, which has existed for over 90 years. We provided turnkey services and maintained regular communication with the client to make sure they were satisfied throughout the project. Ultimately, by replacing the failed transformer with an updated, larger transformer, we have improved the reliability and efficiency of electricity for the community.

Anne Arundel Mobile transformer

A mobile transformer helps provide customer reliability until the new transformer has been commissioned.

Anne Arundel Mother pit

The clay mother pit is being replaced with a new concrete lined mother pit to protect the environment from the transformer’s insulating oil.


The original prints for this substation were hand-drawn by drafters and engineers. Delta reconciled the original prints with these modern, computer-generated prints.

Anne Arundel Substation aerial

Delta provided turnkey services for this substation project and worked safely and effectively to meet the client’s needs.

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