Density of currents and of withstand electric charges admissible for the conductors

The designer of electrical power systems needs rules of thumb to maintain a full understanding of the circuits sizing and of the results obtained adopting available software programs. At this aim, it appears useful to consider characteristic current densities for the conductors in a tentative of a new approach. Steady current densities support the criteria of sizing the circuits for their continuous operation in the time and for their configuration in the load “space” of the system. Transient current densities characterize the cables withstand behavior. The paper identifies withstand electrical charge densities for overcurrents in relation to assigned intervals of overtemperature. For each assumed transient time, the current densities in the conductors are admissible until they accumulate a charge density not greater than the withstand value.