Engineering and upgrades for a 500–230kV substation featuring a 500kV ring bus and a breaker-and-a-half (BAAH) configuration on the 230kV system. 

 
Project Scope:

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• Replacement of two banks of single-phase autotransformers (525–230/13.8kV, 600/800/1000 MVA), including reconfiguration of primary, secondary, and tertiary bus systems to align with new bushing arrangements. Work also included updates to disconnect switches and lightning arresters.

• Structural modifications included new steel supports and foundations where required. While existing transformer foundations were reused due to the smaller footprint of the new units, oil containment systems and firewalls were upgraded to meet current standards.

• Containment improvements included removal of existing earthen berms and installation of a new reinforced concrete containment basin and walls.

• All five firewalls were extended by 5 feet to improve separation and protection between transformer banks. This required installation of 16 helical piers per firewall to support the extensions, along with refurbishment using new fireproofing sealant.

• Existing protection and control systems were evaluated and modified to accommodate new transformer features, including integration of online dissolved gas analysis (DGA) monitoring.
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Key Outcomes:

• Increased system capacity and operational flexibility with upgraded high-capacity autotransformers

• Enhanced reliability and protection through modernized bus configurations and control systems

• Improved safety and environmental compliance with upgraded containment systems and firewall extensions

• Optimized use of existing infrastructure, reducing overall project cost and construction impact

• Extended asset life and improved condition monitoring through integration of advanced diagnostics (DGA)

Project: 500-230kV Ring Bus and BAAH