Save Article Instructions
Close 

Tech Briefs

NEMA releases new motors and generators standard

The National Electrical Manufacturers Association announces release of a new standard, MG 1-2006, Motors and Generators. This standard, an update to the 2003 edition, provides more than 500 pages of manufacturing and performance data related to electric motors and generators.

MG 1-2006 is intended to assist users in the proper selection and application of motors and generators. It contains practical information concerning performance, safety, testing, construction, and manufacturing of alternating- and direct-current motors and generators. Revisions since 2003 are designed to address changes in user needs, technology advances, and changing economic trends.

In addition to being available in hard copy, the standard can be purchased as a CD-Rom. A network pricing option allows simultaneous users. Costs range from US$290 for a network version with one user to US$970 for a network version with 11 to 20 users.

– To purchase a CD-Rom version or hard copy for US$236, a CD-Rom and hard copy set for US$355,or a network version, call (1) 303-397-7956 or visit the Internet: www.nema.org/stds/ mg1.cfm.

Reclamation releases guidance on fish protection at water diversions

The U.S. Department of the Interior ’s Bureau of Reclamation offers Fish Protection at Water Diversions: A Guide for Planning and Designing Fish Exclusion Facilities. This technical publication is intended to provide guidance for fish protection at small dams and water diversion structures by providing fish exclusion alternatives.

Click here to enlarge image

The 480-page manual, published in April 2006, focuses on Reclamation ’s experience in planning and designing fish exclusion facilities for water resources projects. The manual covers several topics:

– Responsible fish resource management;

– Regulatory responsibilities with regard to fish protection;

– Design criteria and guidelines (biological, behavioral, and hydraulic considerations);

– Fish exclusion alternatives, including screens, upstream and downstream barriers, and behavioral avoidance methods;

– Design details for positive barrier screens and behavioral barriers;

– Case studies;

– Post-construction and performance evaluation; and

– Exclusion barriers for upstream migrating fish.


Hydropower Generation Report
Click here to enlarge image

Reclamation plans to develop a second volume of this report that covers fish passage using fish ladders, including upstream and downstream passage for adult and juvenile fish; improvements in reservoir and river operation for control of temperature and dissolved gases; and habitat enhancement.

– To print a copy of the manual, visit www.usbr.gov/pmts/hydraulics_lab/ pubs/manuals/fishprotection/index.html.

Geomembrane liner reduces seepage through a dam

Installation of a geomembrane liner on the upstream face of Salt Springs Dam reduced seepage through the structure by nearly 50 percent in the first year, says dam owner Pacific Gas & Electric Co. (PG&E). Water from the reservoir supplies a 44-MW powerhouse.

During construction of the concrete-faced rockfill dam between 1928 and 1931, initial rock placement techniques resulted in poor consolidation. This fact was recognized as a result of large settlements measured during the first year of construction. Placement techniques used during the following years of construction were improved by reducing the lifts and sluicing with more water to achieve better consolidation. However, the initial rock placement procedures left the dam with an inherent settlement problem. This necessitated numerous repairs to the concrete face over the following decades to reduce seepage.


The geomembrane liner installed on the upstream face of Salt Springs Dam in California reduced seepage through the structure by nearly 50 percent in the first year.
Click here to enlarge image

Because of continued settlement of the rockfill, concrete repairs to the face did not provide for a satisfactory long-term solution. After considering several alternatives, including concrete refacing and an asphaltic concrete overlay, PG&E proposed installing a flexible geosynthetic membrane system over about 65 percent (about 226,000 square feet) of the existing concrete face. This proposal was endorsed by PG&E ’s independent board of technical consultants and approved by the Federal Energy Regulatory Commission and the Division of Safety of Dams in 2003.

Installation of the geosynethetic membrane system was performed by Carpi USA Inc. of Roanoke, Va. The system consists of a geotextile, placed directly on the rough surface of the upstream side of the dam to smooth irregularities. The geotextile is covered by a 2.5-millimeter-thick geocomposite material.

Installation took place over two winters and was completed in the spring of 2005. Cost to install the liner was about $26 per square foot, PG&E says.

Gannett Fleming in Camp Hill, Pa., performed a seepage analysis in 2005 to determine limits for the liner installation to optimize seepage reduction. Overall seepage with a full reservoir was reduced nearly 50 percent, to 15.9 cubic feet per second (cfs) from 30 cfs in the first season of operation. Seepage in 2006 dropped to 12.2 cfs, probably as a result of resilting of the groins that had been exposed beyond the limits of the liner.

Dam removal clearinghouse announces official launch

The Clearinghouse for Dam Removal Information is now available. This clearinghouse is the result of a five-year joint effort by the Aspen Institutes Dialogue on Dams and Rivers – Clearinghouse Task Committee and the University of California, Berkeley ’s Water Resources Center Archives. The goal of the clearinghouse is to serve as an unbiased repository of literature and a place to access electronic information and resources for those making decisions about, or carrying out, a dam removal.

The clearinghouse is available on the Internet at www.lib.berkeley.edu/WRCA/ damremoval. Resources include:

– Case studies of completed or proposed projects, with lessons learned;

– Engineering design plans;

– Dam removal estimates and final costs;

– Permitting documents and applications;

– Monitoring plans and results;

– Modeling data and analyses;

– Scientific studies;

– Project reports;

– Images;

– Conference, symposium, and workshop announcements;

– Proceedings, presentations, and papers; and

– Websites.

In particular, the clearinghouse seeks to capture “gray literature ” that is transiently available when a dam removal is taking place or being considered. Eventually, developers hope the clearinghouse will serve as a platform for posting events and become a forum for carrying on discussions for those interested in dam removal issues.

– To submit information about a dam removal project, visit www.lib. berkeley.edu/WRCA/damremoval/submit.html.

Map shows generating facilities in the Pacific Northwest

The Northwest Power and Conservation Council announces availability of a brochure and website, Electricity Generation for the Pacific Northwest. This brochure – and the corresponding website at www.nwcouncil.org/ maps/power/Default.htm – provides detailed information about all electrical generating facilities in Washington, Oregon, Idaho, Montana, and Wyoming.

Information provided in the brochure includes: type of project, megawatt capacity, owner, and state. Clicking on a project marker on a map on the website provides basic information, as well as a link to more information, both on the Northwest Power and Conservation Council and on websites hosted by the owner/operators.

Click here to enlarge image

The brochure summarizes the electricity supply capacity in the Pacific Northwest by fuel type. Total capacity is nearly 53,000 MW. A vast majority – 63.6 percent – of this capacity is provided by hydroelectric facilities. Coal provides 14.3 percent, natural gas 14.2 percent, and wind 3 percent. Nuclear, biomass, and other facilities provide the remaining 4.9 percent.

In addition, over the past 23 years (since 1983), energy conservation measures have equated to 2,900 MW.

Because of the large quantity of power plants in the Pacific Northwest, those in the brochure and on the website are 50 MW or larger. For a complete list of power plants in the area, visit www. nwcouncil.org/energy/powersupply/ existingprojects.xls.

– To print a copy of the brochure, visit www.nwcouncil.org/maps/power/ print.pdf.

Evaluating fish passage alternatives at Rocky Reach

Chelan County Public Utility District (PUD) is using a computational fluid dynamics (CFD) model of the reservoir upstream of its 1,287-MW Rocky Reach Dam to determine the most cost-effective way to improve guidance and survival of juvenile sockeye salmon passing the project.

Current fish passage tools in place at the project, which is on the Columbia River in Washington, consist of a surface-oriented bypass system and bar screens in two units near the heaviest fish passage area. A conduit conveys fish to the tailrace.

Now, Chelan County PUD is looking at finding ways to further improve fish passage via changes to powerhouse operations and/or physical structures at Rocky Reach Dam. The CFD model covers an area extending 5,000 feet upstream of the project.

A team of fish passage, hydrodynamics, and fish behavior experts are reviewing the alternatives developed via CFD. The work is to be completed by August 2007.

Preliminary results of model testing indicate that modifying the loading of the powerhouse during the outmigration of sockeye may increase the number of sockeye using an existing turbine bypass route.

Development of the CFD model and assessment of the alternatives is estimated to cost about $185,000. The Iowa Institute of Hydraulic Research developed the model.


To access this Article, go to:
http://www.hydroworld.com/content/hydro/en/articles/hr/print/volume-26/issue-1/departments/tech-briefs.html