NEI was hired by Utility Engineering of Denver as a sub-consultant to design the utility interconnectoin, all medium and high voltage systems, all protective relaying, and to specify major equipment for the addition of a 50 MW gas turbine to the existing Valmont power plant. The complete design consisted of removing an existing two winding transformer and its protective relaying that served the unit 7 generator, and replacing it with a three-winding transformer that would serve both the existing unit 7 generator and the new unit 8 generator.

The protective relaying for unit 7 was removed and redesigned to accomodate both units 7 and 8. The new unit 8 is a 50 MW General Electric LM6000 gas turbine. The generator transformer is a three-winding 72 MVA base rating 13.2 to 115 kV transformer delivering power to Xcel Energy's 115kV transmission system.

NEI worked with Utilty Engineering's designers and drafting staff to produce the electrical engineering design documents for the interconnection of the plant to the utility and all protective relaying, and meduim and high voltage system designs. NEI performed short circuit and coordination studies and provided relay settings. NEI coordinated the design with the local utility to comply with their interconnection guidelines.

NEI also aided the Utility Engineers to resolve problems during plant startup and commissioning.

We also provided testing and commissioning services and aided in plant startup.

NEI provided the following services:

• Conceptual and detailed design of 115kV and 13.8 kV electrical system
• Protective relay design and wiring diagrams
• Submittal evaluation for major equipment
• Relay settings
• Equipment specifications
• Project engineering support
• Coordination with utility
• Aid during startup

Plant went on line June 2001.

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