What is the Pantone equivalent to color RAL 3020?
I cannot give you an answer. First of all the Pantone system is proprietary and not related to colorimetry. Second the RAL designation you gave is also a simple index and not related to colorimetry. Some RAL designations are directly related to CIELAB coordinates, but even with such an RAL designation, it would be impossible to convert to Pantone numbers without their proprietary look-up tables (or licensed software that includes them). Your best bet is to inquire with Pantone on how to do this conversion.