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Designed in the early 1950s and opened in September 1956,
California's Richmond-San Rafael Bridge is a 5.5-mi.-long
structure spanning the southern end of San Pablo Bay. The
four-lane cantilever and truss bridge is part of I-580 and
connects the cities of San Rafael in Marin County and Richmond
in Contra Costa County.
Now carrying more than 12 million vehicles per year, the
Richmond-San Rafael Bridge is a vital part of the traffic
network in the San Francisco Bay Area. The bridge, however,
is located between the San Andreas and Hayward faults. A major
seismic event in this geologically active area could result
in catastrophic damage to the bridge.
The California Department of Transportation, Caltrans, currently
is conducting a $363 million seismic retrofit of the Richmond-San
Rafael Bridge. This retrofit is designed to protect that bridge
against failure during future earthquakes.
A continuous power source is critical during nearly five
years of construction on the bridge. Two different power grids,
emanating from each end of the bridge, supply permanent electrical
power. Power outages are common, however, necessitating the
use of reliable backup power for deck illumination, United
States Coast Guard navigation lights, traffic control, call
boxes, and the toll plaza.
Morisoli Construction Inc., the electrical contractor on
the Richmond-San Rafael Bridge retrofit project, selected
gensets from Generac Power Systems Inc. to provide the critical
standby power system. Four diesel gensets have been put into
place: two 150-kW units, one 200-kW unit, and one 300-kW unit.
Four units were necessary due to the length of the bridge,
which includes the approach, and because two different grids
provide power from either end.
The 200-kW unit is located on the western
shore, and the 300-kW unit is located at the toll plaza on
the eastern shore. The two 150-kW units are located on bridge
Piers 34 and 48. The units all are subject to extremely harsh
environmental conditions, including salt spray, salt fog,
and high humidity. Generac's Mike Kirchner notes that his
company's genset enclosures are designed to withstand harsh
environments. "Our standard is powder-painted steel, which
has very good environmental characteristics in that it's 1,000-hour
salt-spray powder paint." Even so, the two units on the piers
are installed inside weatherproof shipping containers for
additional protection.
Remote Monitoring
The harsh environmental conditions increase the need for
monitoring of the units, especially when they are needed to
supply power for such critical applications. Monitoring is
facilitated through the use of remote computer connections
to the genset controllers. Each controller is supplied with
a modem connected to a dedicated telephone line. This allows
Morisoli's electricians to connect to each genset controller
from a remote PC. "By communicating into the controller,"
explains Kirchner, "you can monitor its output, its voltage,
its frequency; you're able to see all of the engine operating
conditions." By periodically connecting with the unit while
it is running, "you get an idea if the engine is performing
within acceptable parameters. Or [you can determine] if you're
seeing a trend in some parameters starting to elevate; for
instance, if the radiator is blocked, you might start to see
an elevation over time of coolant temperatures."
Communication isn't only one-way for the controller. "It
also has the capability, when a controller has a problem,
to call out to a PC that's running the software and to log
that it had an alarm condition." Problems can be diagnosed,
and possibly solved, remotely from the office.
Unauthorized access to the gensets' controls is a natural
concern in today's terror-threatened environment. Access,
however, is password-controlled to allow only authorized users
to remotely interact with the genset controller software.
Kirchner relates, "There is a multilevel password scheme,
such that it's one application program, but if you don't have
adequate passwords for that controller, you can't get into
certain features. There are certain things that an end user
just doesn't need access to on a regular basis."
Communication lines were already in place on the Richmond-San
Rafael Bridge, so the basic telephone landlines were a simple
choice for this application. For more remote applications,
however, nearly any other communication medium can be used.
Generac is migrating to a controller that has multiple communication
ports, including RS-232 and RS-485 ports in addition to the
standard internal modem. "Fiber, satellite, or cellular can
be arranged external to the controller," says Kirchner.
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| The Richmond-San Rafael Bridge
carries an average of 65,000 vehicles per day. Four Generac
diesel generators are providing standby power during a
multiyear seismic upgrade project that will improve the
bridge's ability to withstand earthquakes. |
Remote access has not always been a primary feature of Generac's
products. "The software we use to communicate to our controllers
has kind of evolved over the years," Kirchner explains. "As
we offered the engine controller for gensets of a digital
nature that had communication capabilities, we wrote a software
program to communicate to our controller to allow it to pass
information back and forth. For the most part, it was something
that most of our dealers and most users in the standby market
didn't leverage very heavily."
Generac currently is improving the capabilities of its controllers
and remote-access software. "We're in the process of relaunching
our digital control platform," Kirchner says. "In the most
recent release, that communication software is going to be
a pivotal component of the product. We've reached the point
where it's just not feasible to interact and interface with
the control system because it's gotten so capable and full-featured,
and we need to interface with it through software."
The new control platform can perform additional functions,
such as remote data trending. "I can choose certain parameters
to log and trend and pass from the controller to our software,"
Kirchner notes. "The software is also going to be the interface
for all sorts of programming and reprogramming of our controllers.
It will be possible to download a complete configuration into
a genset remotely. It's even possible to totally reprogram
from the ground up one of our controllers using our software
remotely."
Other Features
In addition to the genset controllers, Generac makes other
customizations to the generator engines. The Richmond-San
Rafael Bridge generators use 7.5- and 12-lit. long-block engines
that were supplied by a third-party manufacturerÑGenerac works
with large suppliers such as General Motors, Ford, Toyota,
Mitsubishi, John Deere, and Detroit DieselÑand customized
by Generac according to Generac's own specifications.
"We source long-block components, basically a seven-eighths-complete
engine," says Kirchner. "Then we will redefine that engine,
Ôreturbomap' it, and Ôre-production-' and Ôreprototype-test'
it to our standards. We take on full parts-service, warranty,
and emissions responsibility." If necessary, the original
engine manufacturer will redesign the engine before production
to meet Generac's specifications for piston and head design,
compression ratios, cam profiles, rods, crankshafts, and bearings.
Generac adds its own external fuel-supply systems, air-supply
systems, and fuel-ignition systems. Customized cooling and
exhaust also are added to optimize the systems for their intended
uses.
For More Information
The following companies were discussed in this article and
can be contacted directly for additional information:
- Generac Power Sytems Inc.
www.generac.com
P.O. Box 8
Waukesha, WI 53187
262/544-4811
- Morisoli Construction, Inc.
5933 Northfront Rd.
P.O. Box 2762
Livermore CA 94550
925/455-1931
- Energy Systems
7100 Longe St. #300
Stockton, CA
209/983-6900
Author THOMS M. ROTH, P.E., is a geological
engineer with Parson's Engineering Science in Atlanta, GA.
DE - March/April 2004
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