arcing horns on distribution line insulators

[KillBill7]

Anyone here with the experience of using arcing horns on distribution voltage (35kV) overhead Powerline insulators? We have one old line which has ceramic insulators with the creepage distance not suitable for the area, so we are evaluating the option to replace the insulators with the polymer type with higher creepage distance. The existing installation has arcing horns installed on each side of the insulator, I haven't seen arcing horns in distribution application and my understanding was as the distribution insulators are small, adding arcing horn would further reduce the air gap and offer alternate path for arcing current. So I am wondering would it be even worth it to change insulator to polymer type with higher creepage distance while leaving the arcing horns on each side? or would it be better to consider removing the arcing horns in addition to changing the insulators.

 

[RRaghunath]

Arcing horns are not required at this voltage level, that too, with the use of Gap-less surge arresters, the residual voltage is low at the time of Lightning strike. (Hope Gap-less surge arresters are installed at the transformer terminals and at the cable/OHL interconnections)
The lightning strike risk for 35kV OHL being low, there is no need to protect the insulators with arcing horns across the insulators.

R Raghunath

 

[waross]

Are you sure that those are arcing horns and not bird deterrents?

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[KillBill7]

@Waross... yes they are arcing horns

 

[cuky2000]

Using an arcing horn on the insulator helps smooth the potential gradient profile across the insulator and therefore requires less creepage distance.
The voltage profile between the conductor supported by the insulator and the ground is not uniform and is mainly shared in relationship to its self-strait capacitance. Also, the horn gap performs to a certain degree as a surge arrester.