Pressure stress of switchgear and compact substations in case of internal arcs

The internal arc tests of compact substations to prove the safety of personnel in case of internal arcs can be divided in two separate tests if there are maximum permitted values of pressure stress in the different compartments. To ensure that the pressure stress is lower than the pressure withstand capability, pressure relief devices and pressure reducing means are necessary. Under these conditions, the pressure withstand capability of the housing of the compact substation and the incorporated medium voltage switchgear can be tested with simplified, minor expensive tests. However, tests to prove the impact of hot arc gases requires tests under real conditions