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Topic:
Special
Exception (SPEX06-CR-001) for a New 500 kV Switching Station
(Bristers Station) and A Comprehensive Plan Conformance
Determination (CCRV06-CR-002) for the Proposed Switching
Station
Topic
Description:
Dominion
Virginia Power has made application to the State Corporation
Commission for authorization to construct:
1)
A new 500 kV transmission line approximately 8 miles
long, entirely within existing right-of-way and parallel to
the existing Morrisville-Loudoun 500 kV line from the
company’s existing Morrisville substation to a proposed 500
kV switching station in Bristersburg;
2)
Approximately 4 new structures outside the fence at
the Morrisville substation in connection with the
reconfiguration of the termination of the existing 500 kV
lines to accommodate the new 500 kV line; and
3)
The new 500 kV Bristers Switching station to be
located on land previously acquired by the company.
The Special
Exception request is for item 3 above - the new Bristers
Switching Station and future substation equipment that will
eventually be located within the same fenced area. Dominion
Virginia Power has owned this property since the 1970’s.
The site is currently crossed by two (2) existing 500 kV
lines and, according to the applicant, it is electrically a
natural junction point for such a facility. The proposed
Bristers 500 kV switching station will be built to split one
of the existing lines that crosses the site, and become a
terminating point for the new 500 kV line from Morrisville,
creating a three breaker ring.
Background:
The ends of
transmission circuits terminate in switching stations and/or
substations. Equipment at these facilities sense faults on
the transmission lines and open the lines to protect the
system. If a circuit is temporarily out of service, other
circuits connected to the station can carry the additional
load and maintain the power flows needed to serve electric
customers. The proposed new line and station will maintain
and enhance the reliability of the electric transmission
grid. According to the applicant, the facility is necessary
to assure the company’s 500 kV transmission facilities in
Virginia’s Northern Piedmont Region will continue to meet
projected load growth in a manner consistent with North
American Electric Reliability Council (NERC) reliability
contingency guidelines for transmission facilities.
According
to the applicant, if this facility were not built and there
was a loss of a portion of the bulk power system, it would
not only impact the applicant’s customers, it would impact
customers in adjoining utilities including electric
cooperatives such as those that serve a large portion of
Fauquier County. Both Rappahannock Electric Cooperative
(REC) and Northern Virginia Electric Cooperative (NOVEC)
serve portions of Fauquier County and depend entirely on
Dominion’s transmission system to transfer bulk power to
their substations.
Facility:
The
switching station will be a fenced and graveled area (all
within Dominion Virginia property). It includes
installation of three (3) 500 kV breakers, three (3) 500 kV
backbone structures, a control enclosure, aluminum bus,
steel support structures and other ancillary equipment as
required. To accommodate future transmission needs, the
site is planned for two (2) future 500 kV lines and three
(3) future 230 kV lines when they are required. Eventually,
one bank of 500-230 kV transformers consisting of four (4)
single phase units will be required at the site. The new
switching station is designed to accommodate the future
proposed facilities with minimal impact. The site will be
graded and fenced such that the future facilities will not
require expansion of the station.
This site
will be a continuously operating unmanned facility.
Approximately five (5) trips per week would be made to the
site. Control equipment will be housed in appropriate
enclosures. Two 250 watt, HPS 120 V, Photoelectric control
lights with recessed lenses that are rated “dark sky
friendly” by the manufacturer, and two (2) porch type lights
on each side of the control enclosure will be installed.
Site
Selection:
This site
was selected due to its close proximity to the existing
transmission lines to each other and the electrical hub that
it creates. There is no other location in Fauquier County
that is comparable to it. The property is not conducive to
other uses as it already contains 500 kV lines on both its
east and west sides. The fenced area has been located to
the rear of the property to remove it from roadside view,
make use of the area most constructable, and to avoid the
wetlands. Because the facility will be located between the
existing transmission lines, no existing homes will be
closer than they presently are to existing lines.
There are
wooded areas on the site, some of which will be cleared for
the new station and the new 500 kV line entering the
station. Landscaping is proposed at the site; however,
because of clearance issues related to overhead lines,
Dominion must exclude trees from those areas under the
lines. The applicant is currently investigating the
possibility of adding additional screening off site to help
buffer views from adjacent homes.
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