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Enhancing Grid Infrastructure: Warrick North 138kV Ring Bus & Line Terminal Installation

Project Overview

Initially designed by NEI in 2011, the 138 kV switchyard located in Warrick, IN underwent a significant upgrade in 2021. CenterPoint Energy contracted NEI to integrate a new line terminal into the switchyard and convert the existing 5-breaker ring bus configuration to a 9-breaker, breaker-and-a-half configuration.

Technical Highlights

Notable milestones included relocating the existing line terminal and 138kV revenue metering connections from the east end of the ring bus to a new dead-end structure, the addition of four new 138kV, 3000A breakers for the breaker and a-half build-out, and further critical updates.

Electrical engineers discuss upgrade plans at the 138 kV switchyard in Warrick, IN, showcasing the new line terminal and gravel-covered ground, with high-voltage equipment and a clear blue sky in the background, for the Project Overview.
View of ongoing construction at the 138 kV switchyard featuring new 3000A breakers being installed, surrounded by electrical infrastructure, with a crane and construction materials in the foreground, under a partly cloudy sky, representing the Technical Highlights of the project.
Upgraded switchyard structures under a blue sky with complex electrical apparatus, illustrating the breaker-and-a-half configuration and engineering advancements for the Project Overview, with the silhouette of power lines in the background.

Engineering Collaboration

Collaboratively, NEI’s team of electrical and civil engineers partnered closely with CenterPoint’s team to adhere to the deliverable timelines, ensuring the project remained on track. The project requirements presented some unique challenges, particularly from a relaying, protection, and control engineering standpoint.

Expanding the layout from a 5-breaker ring bus with 5 transmission lines to a 9-breaker, breaker-and-a-half arrangement with 6 transmission lines required careful analysis of how the existing relaying zones of protection would need to change to accommodate the new arrangement, and new transmission line. Primary and backup high-impedance bus differential relaying needed to be added to each end bus of the breaker-and-a-half scheme, adding to the complexity. Breaker failure trip and lockout schemes also required careful analysis of how those schemes would need to change to accommodate the reconfigured system, and additional breakers on the main buses. The final result was a protective relaying scheme that would provide complete system protection for all major equipment, and also provide a dependable and secure system to prevent unnecessary and undesirable outages.

Grid Upgrade Success

The upgrade of the 138 kV switchyard in Warrick, IN, demonstrates the importance of engineering in improving grid infrastructure. The transition to a more advanced configuration enhanced efficiency and reliability, serving as a model for future projects.

For guidance on engineering solutions that improve infrastructure, NEI provides expertise. Contact us for innovative approaches to your energy projects.