ABB began to re-design its OVR (Out-
door Vacuum Recloser) in 2000. Using
an international design team, the end
result is a “small” power switch princi-
pally used in power distribution net-
works.
The integrated current sensor and
communication units permit the use
of remote control and the immediate
location and identification of faults. A
compact lightweight housing, devel-
oped in the course of the re-design
process, facilitates fast and easy instal-
lation of the device as a unit. It con-
sists of a housing with three poles, a
drive, position indicators and a con-
trol and remote communication unit.
The main component of the recloser
is the vacuum interrupter chamber,
encapsulated in outdoor epoxy resin.
The chamber enables all necessary
switching operations. Such chambers
are capable of completing a very large
number of switching cycles without
the need for maintenance, and pres-
ent no ecological threats. The resin-
molded enclosure reduces the number
of moving components and extends
maintenance intervals. It also im-
proves the resilience to acts of vandal-
ism. Polyurethane has been replaced
as an insulating material by Cy-
cloaliphatic epoxy resin. This material
is suitable for outdoor applications
and ensures longer fault-free opera-
tion of the device.
Two types of devices were developed:
One for operational voltage levels
ranging between 15.5 and 27 kV; and
the second one for voltage levels up
to 38 kV. The higher voltage levels
required a different type of vacuum
chamber, and hence larger dimen-
sions. The structure of the OVR, how-
ever, for both types remained basical-
ly the same .1
The reactive molding simulation
(based on the Automated Pressure
Gelation (APG) process) used tech-
niques developed by ABB Corporate
Research during the RAMZES project.
RAMZES (ReActive Molding ZEro-de-
fects Solution) is a 3-D computer sim-
ulation tool that provides information
to identify what happens during the
critical molding and gelation process.
The data can be applied to the design
of the mold itself, and to key variables
like resin temperature, injection pres-
sure, mold temperature scheme, posi-
tion of inlet channels and the initial
temperature of internal parts. This in-
formation helps overcome common
molding problems, such as premature
gelation, undesired weld-lines and air
traps.
These simulation methods are based
on the commercial, three-dimensional
FLUENT software. They incorporate
two models: the Macosko viscosity
model and the Kamal curing kinetics
model - both describing the ther-
mosetting material (epoxy resin).