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Arcing Horn

Arcing horns are projected conductors used to protect insulators in high voltage transmission lines. They provide a path for flashovers to occur through the air between the horns, rather than damaging the insulator. This allows excess voltage from events like lightning strikes to arc between the horns, which are more durable, rather than going through the insulator. They work by creating a small spark gap with a lower breakdown voltage than the air path along the insulator, diverting overvoltage away from the insulator surface. This gives time for faults to be detected and cleared by circuit breakers.

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616 views2 pages

Arcing Horn

Arcing horns are projected conductors used to protect insulators in high voltage transmission lines. They provide a path for flashovers to occur through the air between the horns, rather than damaging the insulator. This allows excess voltage from events like lightning strikes to arc between the horns, which are more durable, rather than going through the insulator. They work by creating a small spark gap with a lower breakdown voltage than the air path along the insulator, diverting overvoltage away from the insulator surface. This gives time for faults to be detected and cleared by circuit breakers.

Uploaded by

Sureshraja9977
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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2/21/2017 What is an Arcing Horn?

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What is an Arcing Horn?
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and Working Principle
take place which will shatter the Insulator. To prevent Insulator
Symmetrical Fault and Short from such an occurrence, it is very important that flashover do
Circuit kVA not take place through the Insulator. Arcing Horn serves this
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http://electricalbaba.com/what­is­an­arcing­horn/ 1/4
2/21/2017 BOOKS What is an Arcing Horn? | Electrical Concepts

 
As  shown  in  figure  above,  Arcing  Horn  isnormally  paired  on
either  side  of  the  Insulator,  one  connected  to  the  high  voltage
side of Insulator and the other to ground.
Working Principle of Arcing Horn:
Arcing  Horn  bypasses  the  high  voltage  across  the  Insulator
MY FAVORITE BOOKS using  air  as  a  conductive  medium  between  the  Horns.    The
small gap between the horns ensures that the air between them
breaks  down  resulting  in  a  flashover  and  conducts  the  voltage
surge rather than cause damage to the insulator.
 
Arcing  Horn  basically  form  a  Spark  Gap  across  the  Insulator
with  a  lower  breakdown  voltage  than  the  air  path  along  the
insulator  surface,  so  an  overvoltage  will  cause  the  air  to  break
down and the arc to form between the arcing horns, diverting it
away  from  the  surface  of  the  insulator.  An  arc  between  the
Horns  is  more  tolerable  for  the  equipment  because  it  provides
more  time  for  the  fault  to  be  detected  and  the  arc  to  be  safely
cleared by remote Circuit Breakers.
 
At  medium  voltages,  one  of  the  two  Horns  may  be  omitted  as
the  Horn  to  Horn  gap  can  otherwise  be  small  enough  to  be
bridged by a bird.
 
The presence of the arcing horn necessarily disturbs the normal
electric field distribution across the insulator due to their small
but significant capacitance. More importantly, a flashover across
arcing horn produces an earth fault resulting in a circuit outage
until the fault is cleared by circuit breaker operation. For this
reason, non­linear resistors known as varistors can replace
arcing horns at critical locations.

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1. Theory of Arcing Ground-Ungrounded System 
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