Single point and
double point arcing horns in galvanized mild steel flat type upto 69 kV, round ball ended type upto 138 kV and Pipe Type upto 230
kV are available.
For voltage of 380 kV or above corona rings are supplied normally made of
aluminiun alloy.
The values for radio interference voltage , corona protections are always kept below the normal internationally specified limits.
Power Transmission Lines should be provided with maximum
possible service safety to avoid possible damages to
insulators and conductors.
Flashover is often the cause of outages due to high arc
temperature which may damage the conductors and destroy
the insulators. Arcing protections an important feature
of equipment design. They consists of horns, Grading
rings, the shapes and sizes of which are in accordance
with system voltage and standardised by High Voltage
Electrical Tests. Aluminium Corona Control Rings are
supplied for High Voltage applications above 330 KV. A
properly designed protection device will avoid the
flashover damaging the insulator string. It will make
the arc start away from the line conductor and ensure
that during all the flashover time the arc is kept away
from the insulator string. The ring shape design give a
more linear voltage distribution all along insulator
string, thus avoiding bottom insulator from Electrical
over stress. While for system voltage upto 220KV
conventional flat type, ball and rod type and tubular
racquet type arcing horns are adequate for UHV lines
i.e. 400KV and above special designs are developed.
RUL
has conducted extensive test on various design to
optimist its performance under fault conditions. The
range is wide both from configuration and size and this
catalogue illustrates the basic form of some of the
commonly used designs. The arcing/grading rings are
produced both in steel (HDG) and satin finish aluminium
alloy tube (UHV application).
