Electronic – Handling Hi voltage and very low current (10 mA) will need to prevent arc and corona effects on the PCB

high voltageleakage-currentpcb-designrelay

I' m following this guide; concretelly 3 and 4 chapters for High Voltage (HV) PCB design:

https://www.magazines007.com/pdf/High-Voltage-PCDesign.pdf

The fact is that I have read interesting ways to avoid arcs and coronas between to high voltage conductors.

I have found here some of them as for example:

  1. Field gradient rings
  2. Routed Slots
  3. Inert Insulators
  4. Cover Coats for solder mask with Kapton
  5. Dielectric strength sheets material
  6. Rounded copper shapes

I must to design a board with some HV relays, 8 points x 2 relays. Every relay will connect some of these points to a source positive terminal. This High voltage will arrive to the every relay by a wire from an industrial HV source.

HV source is an external device that brings energy to the board relays towards H and L terminals:

enter image description here

Although the board or relays will handle a max of 10KV the application only will need a few mA from the HV source.

Board will only have relays, connectors and not too much elements apart of these; maybe some diode, decoupling C if needed or even some R (depends on relay specs). Relays coils will be fed by low voltage (12V or 24V).

My question here are:

  • Will I really have arc and coronas problems to avoid with this little
    current consumption: few mA (5, 10, etc)?
  • Will I really need to use those techniques: upper dielectric strength material for the sheet, routed slots to prevent carbonation of board, Kapton Cover Coats for increasing the dielectric strength of the board, etc.. or can I still using low voltage PCB design materials and techniques?
  • At page 14 autor says that "corona and leakage current from the field must be calculated o experimented with" when designing pcb. How can I calculate corona and current leakage effects? So in case I get them, how must I use them?

Best Answer

I'd also take a look at the IPC 2221[edit: Electrical Clearances] standards before going any further with the PCB design. For a high voltage PCB, the one thing that matters the most is the material selected for the core/prepreg. Depending on the availability and budget, you can go with extra overcoats and better alternatives/versions of FR4. Also, consider a Kapton Overcoat if possible.