The Dalles Exciters

There are four families of generators at The Dalles powerhouse.  The excitation systems for these units vary in model and installation dates and there has generally been decreased availability of spare parts and support from the original equipment manufacturers (OEMs) for all units with one, as well as other ongoing maintenance and cybersecurity concerns.  The objective of the Phase 1A report was to capture the existing conditions and concerns, to identify performance requirements and criteria and constraints for various potential paths forward (called “Alternatives”), evaluate these various alternatives for viability and comparative value, and perform scoping and economic analysis to progress towards successful execution of the selected alternative.

Based on comments made by the PDT, the Value Team identified the most important functions that needed to be addressed were to reduce unplanned outages by reducing risk, improving reliability, eliminating obsolescence, increasing redundancy, and simplifying maintenance.  Numerous risks (primarily to the project cost and schedule) were also identified including a limited skilled construction labor force, limited number of bidding supply and install contractors, potential bottlenecks in the manufacturing process, and inexperience in the complexity associated with installing brushless exciters in a retrofit scenario.

The VE study focused on reducing risk, improving reliability, eliminating obsolescence, increasing redundancy, optimizing procurement, promoting constructability, preserving standby power, and simplifying maintenance.  The proposed VE savings were approximately 42% of the capital cost.