Power Definitions for Nonsinusoidal Unbalanced Three-Phase Four-Wire Systems with Different Neutral Conductor Resistance

This paper defines active currents that minimize line losses while ensuring the same active power transfer to the load in a three-phase four-wire system, where the neutral conductor resistance differs from that of the phase conductors. The problem is analyzed using the calculus of variation technique. The proposed minimization approach results in power definitions that, in specific cases, align with well-established power definitions for sinusoidal, nonsinusoidal, balanced, and unbalanced conditions.