HOW TO DESIGN AN ARCING HORN FOR SAFE FLASHOVER IN HIGH VOLTAGE LINES

high power High voltage Transformers
By Majdi EL Fahem | 01/09/2021

WHAT IS AN ARCING HORN? 

Arcing horn is made of two conductors where one is connected to the high voltage line and the other one is connected to the ground, separated by an air gap.  If and when an over voltage occurs due to a lightning strike, a sudden load variation, or any other faulty condition, a flashover shall take place through the conductors and the airgap arc.  Otherwise, the flashover would go through the bushing insulators and damage them. 


Arcing horn [1] 


THE ARCING AIRGAP 

The spacing between the two conductors, or the airgap, gets ionized and, ironically, becomes a conducting medium. Thus, the flashover finds a safe path to the ground.  Consequently, the size of the airgap is the most critical parameter in the entire design.  It must be carefully dimensioned for a variety of faulting and voltage conditions.  


SIMULATE IT BEFORE YOU MAKE IT 

Don’t make your arcing horn and start testing it! It is expensive and time consuming! Use the popular EMWork’s virtual prototyping workbench, EMS, to simulate and optimize your design.  Because EMS is an add-in to SOLIDWORKS and Inventor, virtual prototyping your arcing horn has never been this easy.  Being inside the CAD, you shall not need to import, export, or heal geometry.  In addition, EMS is equipped with a powerful post-processor to view field results such as voltage, electric field, displacement field, and more.


Vector plot of the electric field at 50kV  


Electric field lines at 250kV  


Animation of the electric field versus applied voltage


Voltage plot