What defines a nonlinear load in an electrical system?

A nonlinear load in an electrical system is characterized by the condition that the wave shape of the steady-state current does not follow the wave shape of the applied voltage. This behavior occurs because nonlinear loads generate harmonic distortion in the electrical system. When the voltage is applied, the current does not respond in a proportional manner, which leads to distorted waveforms.

Examples of nonlinear loads include devices such as computers, LED lighting, and variable frequency drives. These devices draw current in a manner that can vary significantly with the voltage, unlike linear loads (such as resistive heating elements) which draw current that is directly proportional to the applied voltage and thus maintain a direct relationship in waveform shapes.

Understanding this concept is essential in electrical engineering and the implementation of power quality measures, as nonlinear loads can lead to issues such as overheating of conductors, increased losses, and interference with other equipment in a power system.