Arcing Horn Design: Ensuring Safety in High Voltage Applications

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 overvoltage 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 

Animation of Safety Factor results – detection of breakdown voltage  

SUMMARY AND TAKEAWAYS 

Arcing horns play a pivotal role in safeguarding high-voltage infrastructure against overvoltage damage. By utilizing EMS for virtual prototyping, engineers can refine the critical air gap dimensions, ensuring optimal performance and reliability. This approach not only enhances the safety and efficacy of arcing horns but also reduces the time and costs associated with their development, marking a significant advancement in the protection of electrical systems.

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