In a three-phase, four wire system, which conductor is most likely to be affected by nonlinear loads?

In a three-phase, four-wire system, the neutral conductor is primarily affected by nonlinear loads due to the way these loads draw current. Nonlinear loads, such as computers, LED lighting, and certain types of motors, do not draw a constant current. Instead, they draw current in a non-linear manner, which results in harmonic currents being produced.

These harmonic currents have frequencies that are multiples of the fundamental frequency (e.g., 60 Hz in the U.S.). In a balanced three-phase system, the harmonic currents from the phase conductors can cancel each other out, which means that ideally, the sum of the currents in the three phase conductors should equal zero on the neutral. However, when nonlinear loads are applied unevenly across the three phases, the harmonic currents may not cancel out completely, resulting in a higher current flowing through the neutral conductor.

This increased current can lead to overheating and potential damage to the neutral conductor, as well as other issues such as voltage distortion and increased losses in the system. Thus, it is essential to consider the impact of nonlinear loads on the neutral conductor specifically in a three-phase, four-wire system.