Tech Briefs

First gas-insulated transformer in U.S. installed at Osage

AmerenUE has installed a gas-insulated transformer supplied by Toshiba International Corp. at its 230.75-MW Osage project, marking the first use of this technology at a hydro plant in the U.S.

This transformer uses SF6 gas for insulation and cooling instead of oil. This type of transformer is non-flammable and non-explosive. In addition, use of the gas eliminates the chances of an environmentally-unfriendly oil spill. The unit is more compact than a traditional transformer because it does not require a conservator or pressure relief arrangement, says Yasushi Abe with the transmission and distribution division of Toshiba.

The original transformers at Osage had been in place for nearly 80 years. It was necessary to monitor the transformers continually and to sample the oil every three months to ensure safe operation, says Phil Thompson, plant supervisor at Osage. Because the transformers sit under a highway and above the Osage River, AmerenUE decided to invest in technology that would minimize fire concerns and potential damage to the roadway while also eliminating environmental concerns related to an oil spill.

The remaining six original transformers at this facility are scheduled to be replaced by 2013. Each gas-insulated transformer replaced three of the older transformers, increasing transmission from 14 kilovolts to 140 kilovolts.

The installation was completed in December 2010.

Toshiba has supplied more than 700 gas-insulated transformers worldwide since 1967.

Reclamation releases book on Colorado River management

The Bureau of Reclamation, U.S. Department of the Interior, offers The Colorado River Documents 2008.

This book discusses the Secretary of the Interior’s management of the Colorado River from 1979 through 2008. The book details the statutes, policies, agreements, and court decisions relating to river operations, environmental matters, Mexican treaty deliveries, water development, water entitlement actions, Native American water settlements, proceedings in Arizona v California, and power generation and distribution issues that have occurred over the past 30 years.

This book is the fourth of a series describing influential legislation and actions affecting the Colorado River, says Lorri Gray-Lee, regional director of Reclamation’s Lower Colorado Region. The other three books are Updating the Hoover Dam Documents 1978.

The book comes with a DVD that includes the complete text of all four books and all source documents.

– The book and DVD can be purchased for $87 or the DVD alone for $14 at

Developing a method to determine equipment obsolescence

Engineers with Avista Corp. have developed an objective method for determining when a component or piece of equipment is obsolete.

Rodney Pickett, PE, and Steve Wenke, PE, used multiobjective decision analysis. This method uses value functions to convert qualitative and quantitative measures into a quantitative value that can be used for specific guidance on equipment obsolescence. These quantitative values represent the decision-maker’s values associated with each evaluation measure and its associated scale. When the method is complete, the outcome reflects a unique value for the decision-maker. The multiobjective decision analysis method incorporates not only ranking of work but also a go/no go decision point.

This method allows Avista to use evaluation measures as inputs to the quantitative model. The six evaluation measures chosen are:

– Meet data requirements, the ability to meet necessary data requirements for the operation and management of the asset or piece of equipment;

– Maintenance personnel training and experience, the experience and training programs for personnel or manufacturers to support an asset;

– Equipment manufacturing life cycle, where the asset is in terms of the manufacturing life cycle;

– Spare parts availability, the availability of spare parts to continue to maintain the asset;

– Software life cycle, where the product is in terms of its software life cycle; and

– Security requirements, the ability of the asset to meet the security requirements for cyber or physical security.

Pickett and Wenke then developed units of measure for each of the evaluation measures and translated these units into a value function. An Excel spreadsheet was used to implement the multiobjective decision analysis process. The equation uses the value function and its associated weight factor for each evaluation measure. An evaluation was performed in May 2010 of several components, including generator breakers, governors, programmable logic controllers, and penstocks. Results of this evaluation indicated which items were obsolete and provided a numerical ranking for prioritization.

The method has been successfully applied on a limited basis. The tool focuses strictly on obsolescence, not on risk of failure of the financial impacts of those failure risks, Pickett and Wenke say. Thus, it is part of a broader effort to establish a more sophisticated asset management program. When used with a more traditional risk-based life cycle asset management system, the tool provides a more complete picture of the condition of the asset and acts as an input to developing an overall plan for managing hydro assets.

Bartojay named Reclamation engineer of the year

Katie Bartojay has been named Engineer of the Year by the U.S. Department of Interior’s Bureau of Reclamation for her work on several high-profile projects, including 198.72-MW Folsom and the Warren H. Brock Reservoir.

Bartojay is a civil engineer in Reclamation’s Materials and Engineering Laboratory in Denver, Colo. She manages large-scale laboratory investigations for mass concrete mixtures and field investigations of deteriorating concrete. She provides technical advice throughout Reclamation to resolve concrete construction problems and to assist in creating project specifications for a wide variety of concrete features. Bartojay also is the primary technical construction materials contact for Reclamation with the U.S. Army Corps of Engineers.

Significant work is under way at Folsom to address hydrologic risk identified by Reclamation’s Safety of Dams program, including construction of an auxiliary spillway and control structure. For the Warren H. Brock Reservoir, Bartojay wrote the materials section of the Quality Assurance Manual. The new reservoir is being built at a cost of $250 million to capture water being lost from the Colorado River’s water delivery system.

Reclamation operates 58 hydro plants that annually provide more than 41,000 gigawatt-hours of electricity.

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