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Substation — Welded/EHV
BURNDY
®
Canada: 1-800-387-6487
www.burndy.com
US: 1-800-346-4175
M-8
RADIO INTERFERENCE
VOLTAGE
There is serious question as to whether
measurement of RIV on connectors makes a
meaningful contribution to quieter station
operation.
Under test conditions, there is generally no
significant indication on the radio noise
meter until the onset of visible positive coro-
na. At this point, the RIV reading goes into
the hundreds of thousands of microvolts.
The effect of this phenomenon is to provide a
visibly discernable point at which RIV will
become excessive. It eliminates the necessi-
ty to make, record and plot RIV measure-
ments. Where there is no corona, there is no
RIV. So our test criterion calling for no visible
corona insures that there will be no radio
interference generated by the connector
under operating conditions.
EFFECT OF CONDUCTOR
SIZE ON TESTING
Conductor diameter has a significant effect
on potential corona problems. The larger the
diameter, the lower the surface voltage gradi-
ent for a given test voltage. This means that
smaller conductors produce corona at lower
voltages than larger ones.
Many connector designs have the same
basic configuration for various conductor
sizes. The only difference being the size of
the attaching elements. This is particularly
true for many of the welded type connectors.
Where this is the case, it is often sufficient to
test the connector only on the smallest con-
ductor, since it yields the lowest corona
extinction voltage. When there is any doubt,
each size is tested.
CONTAMINATION
Much work has been done to establish the
relationship between the corona onset
voltage for contaminated as compared to
clean hardware. Experiments in the
BURNDY
®
laboratory indicate that this value
can be reduced to half of the voltage for
clean hardware. However, the relationship
varies with the kind of contamination, atmos-
pheric condition and type of connector.
There have been a number of attempts to
produce artifical contamination and atmos-
pheres in laboratories. However, there is as
yet no clearly established relationship
between the corona performance of hard-
ware contaminated in the laboratory. Until
such a relationship is established, the only
testing that provides comparable data is on
clean hardware under fair weather
conditions.
CONCLUSION
For more than 80 years, BURNDY
®
has been
designing connectors for the industry’s most
critical applications. Connectors for EHV are
an outgrowth of this tradition. Whether your
need is for catalog items or special designs,
you can count on electrical, mechanical and
corona-free performance, commensurate
with the application.
TYPICAL CURVE