What is the method to calculate the radius for barrication during HIPOT Test of Gas Insulated Switch Gear (GIS)?

Commissioning tests are the final check on the cable, in order to pinpoint eventual problems caused during the installation process.These tests consist in the application of Hipot Test for 1 hour thanks to an external source (RTS - resonant testing system). The level of the overvoltage is specified by the specific international regulation.Techimp personnel will provide an accurate measurement in order to verify absence of dangerous Partial discharge phenomena discriminating between possible noises or disturbances.

Sorry, I am into Banking domain. So I couldnt answer this question