POWER June 2014 - 18

Robust Bearings Tested for Brazil's Belo
Monte Hydro Project
Brazil's Belo Monte hydropower project includes a complex of
dams, numerous dikes, and a series of canals supplying two different
power stations with water. With a rated capacity of 11,233
MW, it will be the country's second-largest and the world's thirdlargest
hydropower generating station behind China's Three Gorges
and Brazil's Itaipu installations.
Project owners wanted a reliable, water- and debris-resistant
material that would allow extended service for the facility's wicket
gates. The components needed to withstand the harsh 24-hour
operating conditions at the dam and provide a minimum service
life of 20 years.
As part of the search process, Norte Energia-the company
formed to build and operate the Belo Monte hydroelectric
plant-tested GGB Bearing Technology's HPM self-lubricating,
filament-wound bearings (Figure 1) to determine their suitability
for the wicket gate application. The materials used in the
bearings were specifically developed for hydropower applications
and offer resistance to impact and corrosion, high static
and dynamic load capacity, and 75% less weight than equivalently
sized metallic bearings.
Powertech Labs conducted the testing in accordance with
U.S. Army Corps of Engineers specifications. The testing simu1.
A 3D view of a self-lubricating, filament-wound
bearing. There have been some locations using this type of bearing
since 2007 with no failures reported. The life expectancy for the material
is at least 20 years. Courtesy: GGB Bearing Technology
lated actual operating conditions at Belo Monte, including the
use of water from the Xingu River, where the project is being
constructed. The bearings were subjected to tests that were
modified to simulate 30 years of operation rather than the standard
13 years.
The bearings-consisting of a fiberglass-reinforced, epoxy
resin support layer and a sliding layer of polyester fibers
with polytetrafluoroethylene and other additives-were first
subjected to a static load with rotary and oscillating motion
under both dry and wet conditions. They then underwent accelerated
wear testing with a dynamic radial load on a journal
moving continuously plus or minus one degree. The static load
remained constant, but the dynamic load was paused every 15
minutes to simulate a turbine wicket gate opening plus or minus
15 degrees.
The bearings performed well with little evidence of operating
stress. Significantly, it was demonstrated that their coefficient of
friction and wear rate decreased as running time increased, which
allowed the project engineers to design the turbines with smaller
servomotors. Engineers now use the essential data provided from
the testing when specifying self-lubricating bearings in hydropower
turbines to achieve longer service life and maintenancefree
operation.
GGB HPM bearings are used in more than 25 hydropower projects
worldwide, including on the largest water turbine in the
world at the Chinese Xiangjiaba hydropower plant. That Three
Gorges Corp. project contains four Francis turbines, each with a
rated capacity of 850 MW, which were fitted with bearings with
an inner diameter of 520 mm and a length of 370 mm. ■
-Edited by Aaron Larson, a POWER associate editor
(@AaronL_Power, @POWERmagazine).
New Enclosure Solution Enables Remote
Monitoring of Battery Backup Systems
With 4.4 million customers and nearly 46 GW of generating capacity,
Atlanta-based Southern Co. has doubled the size of its super2.
GE-MDS radio enclosure system with battery test
remote monitor. The remote monitoring of battery backup systems
was an essential reliability feature for Southern Co.'s supervisory
control and data acquisition system. Courtesy: Ventev
18
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POWER June 2014

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