Rehabilitation – classroom presentations

Presentations are:

Rehabilitation and Modernization of Hydro Generators, presented by Howard Moudy, National Electric Coil

Upper Baker Spillway Stabilization: Construction with Extremely Remote Access—A Contractor’s Perspective, co-presented by Michael Likavec, Puget Sound Energy, and David Laack, J.F. Brennan Company, Inc.

What NOT to do - Lessons Learned in the Rehabilitation of Hydroelectric Power Generating Units, presented by Karen Counes, CDM Smith

Details about each presentation and the speakers are below:

Rehabilitation and Modernization of Hydro Generators
Presented by Howard Moudy, National Electric Coil

The presentation will provide large and small hydro as well as pumped storage users with valuable insight to meet the challenges of planning and executing rehabilitation/modernization of hydro generators. Important planning elements will be shared including timing and duration considerations relative to overall project and components scopes.

Differences between upgrade and uprate will be discussed and important considerations and success factors identified. Supply chain challenges will be discussed, contrasting global and domestic sourcing options and identifying common issues and contingencies. Separate attention will be paid to rotor and stator scopes. New/upgraded components will be discussed with specific focus paid to the important details and factors for the requalification of components intended for continued use.

Critical to quality (CTQ) execution elements will be shared and related to specification elements. Ample photos and illustrations will be used to discuss project execution and will emphasize CTQ elements.

Upper Baker Spillway Stabilization: Construction with Extremely Remote Access—A Contractor’s Perspective
Co-presented by Michael Likavec, Puget Sound Energy, and David Laack, J.F. Brennan Company, Inc.

The Baker River Hydroelectric Project is owned and operated by Puget Sound Energy (PSE) as a multipurpose facility. It is managed for hydropower generation, flood risk reduction, recreation, and fisheries. The Project consists of two developments: Lower Baker Development and Upper Baker Development. Both developments are constructed across the Baker River, a tributary to the Skagit River which flows west into the Puget Sound.

The Upper Baker Spillway Stabilization project targeted potential failure modes identified during the 2019 Part 12D workshop for the Upper Baker Development. Additional evaluation of the geologic conditions, geotechnical analysis, and design were completed to receive Federal Energy Regulatory Commission (FERC)phased authorizations to construct the preferred stabilization alternative.

The project involved constructing a concrete buttress within the river diversion sluiceway channel from dam construction (1956) to stabilize the rock slope that supports the spillway chute. Features of work included developing temporary access to the tailrace, dredging, cofferdam and formwork construction, foundation preparation, concrete placement, drilling, and installation of untensioned dowels.

After temporary access to the river was established, 7,400 CY of material was dredged and unloaded over the course of two months to allow access through the canyon to the abandoned sluiceway. The narrow width of the canyon (60 feet at its narrowest) did not lend itself to traditional dredging methods.

While concrete placement is typically a routine task, the placement location for the 5,200 CY of concrete was over 400 feet away from the delivery location— too far for a pump truck to reach or a crane to swing concrete buckets.

This presentation discusses these challenges the contractor overcame to perform seemingly routine features of work in a remote and difficult-to-access location, the unique procedures and outside-the-box techniques applied, special safety concerns, resolution of schedule impacts, and the critical importance of the strong client/contractor relationship that developed.

What NOT to do - Lessons Learned in the Rehabilitation of Hydroelectric Power Generating Units
Presented by Karen Counes, CDM Smith

There are specific keys to success in the rehabilitation of hydroelectric generation equipment. This session will feature how to plan and execute rehabilitations and upgrades to avoid common pitfalls and implement best practices as experienced by owners, construction managers and engineers.

Planning such a project requires a careful approach and includes such elements as a detailed "bill of materials" (BOM) identifying each component's condition, determination of refurbishment or replacement along with cost estimates. Project delivery method is also critical to determine since each method has its own advantages and disadvantages. Client to determine how much "control or review" is required of the component designs, performance criterion, fabrication and quality inspections. Other things to consider include obtaining reputable vendors and finding available experienced staff willing to commit to the project is very limited. Global sourcing of most equipment is very likely and the present supply chain issues will determine the implementation plan. These planning items, plus others, will be discussed, along with real-world examples of work.

The rehabilitation of hydroelectric generation unit design and construction scope and discussion includes new: turbines, generators (rotors/stator), excitation system, shafts, lubrication systems, seals, servomotors, control systems, instrumentation, wicket gates, bearings and headcovers. Some equipment such as the turbine liner wall and stay ring/vanes may need to be refurbished in place vs replacement. A condition assessment of all equipment and the projected life expectancy is required to determine the overall project scope and cost. Each of these have some specific needs and discussion and cases will be presented to demonstrate key success factors for delivery.

Unfortunately, a substantial amount of existing documentation is required in order to properly perform this assessment. Documentation such as detailed fabrication and installation drawings, material specifications, QA/QC documentation, historical modifications, O&M and performance data, otherwise extensive investigative fieldwork and testing will be required.

Discussion will be presented in cases within the last 20 years and by CDM Smith and the New York Power Authority.

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