Abstract: An apparatus and method applicable to an electric power distribution installation, the electrical power distribution installation comprising: at least one main common bus bar; a plurality of main transformers, each main transformer being configured to step down a received power supply voltage and to supply the stepped down power supply voltage to a load via the main common bus bar; and a plurality of power generators, each power generator being connected to the main common bus bar, and the apparatus comprising: a first grounding device including at least one grounding transformer connected to the main common bus bar, a neutral point of the grounding transformer being grounded in a form of a predetermined low impedance grounding; and a second grounding device connected to each neutral point of the power generators to always ground each neutral point directly in a form of a predetermined high resistance grounding.