I am controlling a high voltage power supply to generate corona discharge. To switch it on and off I am using an AC relay controlled by a microcontroller as shown in the figure.
Now the problem which I am facing is that sometimes during corona discharge there are sparks and when ever it sparks the microcontroller restarts(I know this because when it boots the LEDs blink on the board) and the HV power supply turns off before that one minute duration.
I tried putting the micro and the relay inside a Faraday shield and grounded everything but it does not seems to work. Also, other thing I noticed is that whenever I removed the relay and drive the HV power supply without the microcontroller the sparks have no effect on the controller.
Any suggestions on how to use the HV power supply with the microcontroller and protect it from the sparks?