Electrifying tale

-- A NEW electronic
device, called thyristor-controlled series
compensator (TCSC),
may "revolutionise
the way electricity is
delivered to customers globally".
The first such system was recently
dedicated in the US to the Bonneville
Power Administration's (BPA) Slatt substation in Antral Oregon.

According to a report in (Power
Engineering International, Vol 2,
No 3) of US, the new equipment uses
advanced solid state switches to
expand the capacity of existing
transmission lines, while improving
power quality and systems security.
The recent dedication marked the
successful checkout of the device,
which may ultimately save the US
Utilities an estimated US $6 billion in
construction costs for transmission line
expansion. In addition, Utilities will be
able to delay costly investments in
power plants because the TCSC will
accommodate trades of large blocks of
power between regions, which was previously impossible.

Concept development for the US $19
million demonstration began in 1990.
The project is being co-funded by the
Electric Power Research Institute (EPRI),
BPA, Portland GE, and General Electric,
which designed and manufactured TCSC
under license from EPRI.

The Slatt substation was selected as
the test site because of its high continuous current (2900A) and high short-circuit current (22,000A) ratings. Staged
tests will examine the TCSC's reaction to
a range of challenging conditions and
results will be monitored to ensure that
all aspects of the controller's response
are as planned.

BPA executives expect that the cost of
the new device will be two to three times
that of a conventional series capacitor,
which reduces line impedence but does
not control subsynchronous resonance or damp system oscillations.