Substation Projects

Substation projects can range in complexity from relay control panel upgrades, to feeder bay or capacitor bank additions, to construction management of complete new substations. S&C’s Power Systems Services has the experience and background to handle all aspects of such projects including preliminary engineering, permitting, design, construction management, testing, and documentation. S&C is recognized in the industry as a top-quality provider of substation services and can deliver them in a cost-effective, expeditious manner.

Here are just a few substation related projects S&C has completed:

Relay Control Panel Upgrades

A southeastern U.S. utility wanted to add control and metering to its distribution substation feeders. They decided that a microprocessor- based relay interfaced to their SCADA system would provide the desired control and metering functions plus enhanced protection. It also offered the added benefit of reduced maintenance calibration and testing. But because of their already-demanding workload, the utility could not pursue the project. S&C was contracted to do the work.

S&C’s project manager and team of engineers, designers, and field service specialists:

Provided the site-specific design and documentation required for upgrading the relaying at each feeder,
Contracted a panel fabricator to supply the new relay panels, and
Installed, tested, and commissioned the new control equipment.

The utility saved money because only minimal oversight was required by its project manager, and the cost of overtime by an already-overburdened staff was avoided.

Turnkey Transformer Protection Upgrades

Another southeastern U.S. utility wanted to upgrade the protection at its substations, but didn’t have the staff to accomplish the task. Their existing protection scheme used a motor-operated disconnect to isolate a faulted transformer from the substation high-side bus, after the fault was cleared by line breakers. Through the SCADA system, system operators could determine the location of the fault, re-energize the high-voltage bus and bring the unfaulted transformers back on-line. However, this procedure could take several minutes — or even longer during a storm, when the operators were responding to multiple outages. In the process, power was needlessly interrupted to users served from unfaulted transformers. By applying an S&C Circuit-Switcher or Trans-Rupter II® Transformer Protector at each transformer — with relaying coordinated with bus relays — a faulted transformer could be locally isolated, so service to users served from unfaulted transformers would not be affected. S&C was contracted to:

Provide the Circuit-Switchers and Trans-Rupter II Transformer Protectors,
Design the physical installation of the new equipment,
Design the relaying and controls to interface with the existing relaying, and
Provide construction, testing, and startup services.

All work was completed in advance of the aggressive project timetable, surpassing the customer's expectations.

Turnkey Substation Upgrades

A semiconductor manufacturer in Texas wanted to upgrade an aging 138-kV substation to increase capacity and reliability. They had the general requirements in mind, but turned to S&C for the details and the wherewithal to complete the project. S&C provided a complete 138-kV substation on a turnkey basis — from concept to concrete — in accordance with the company’s engineering standards and operating philosophy. Specific responsibilities included the following:

Concept design — S&C’s team of designers and engineers worked with the customer to complete the concept design, in sufficient detail to ensure the layout would provide adequate clearances and allow for efficient operation and maintenance of the equipment. The new substation includes two 70-MVA 138/13.8-kV transformers with associated circuit breakers and motor-operated disconnects, and 13.8-kV metal-clad switchgear buildings.
Approvals and permitting — Once the concept design was accepted, plan and profile drawings were prepared and the design was presented to the customer's upper management. Local government officials were involved at this stage, to ensure an unencumbered licensing and permitting process.
Design and engineering — All the details of the substation were worked out, including grading, drainage, oil containment, retaining wall location and design, foundation design, replacement and re-location of the two 138-kV transmission towers supplying the substation, bus work connecting the transformers to the switchgear buildings, and underground ductwork and manholes for cut-in to the existing 13.8-kV underground feeders and the new switchgear buildings.
Drafting and construction specifications — Complete, accurate drawings and specifications were developed to facilitate review of contractors’ bids. “Out-of-scope” charges were thus avoided, and bidders could offer their most competitive prices without having to hedge because of unknowns.
Analytical studies — S&C performed harmonic studies and power-factor correction studies to determine the need for, and appropriate size and placement of, harmonic filter banks.
Construction management — S&C provided project scheduling to ensure uninterrupted operation of the facilities while construction was under way, bid package evaluation, subcontractor hiring and oversight, permitting, and close coordination with the local electric utility supplying the facility.
Demolition of existing plant infrastructure and environmental restoration.
Equipment procurement, witnessing of factory tests, field installation, and commissioning of equipment.