What Are Corona Rings on High Voltage Insulators?

[DaveE]

Please explain what these things are for. I'm guessing they reduce the e-field strength at the end of the insulator while maintaining a long creepage path, maybe? Or something about reducing corona discharge?

What are they called? I can't seem to get a good search term.

 

[DaveE]

Found it. It's a "corona ring". More than I really wanted to know in this paper. Although there are some things I still don't really have a good feel for.

https://www.researchgate.net/figure/230-kV-three-dimension-model-of-clean-insulator-with-corona-ring_fig1_303737136

 

[nsaspook]

200kV voltage multiplier with corona rings to help equalize the electric field around the circuits.