Which type of voltages are multiples of the base frequency?

Harmonic voltages are indeed defined as voltage components that occur at integer multiples of the fundamental frequency. In electrical systems, the fundamental frequency is considered the base frequency, usually at 50 Hz or 60 Hz, depending on the region. Harmonic voltages arise from non-linear loads and can affect the performance and efficiency of the power system.

These voltages can distort the current waveform, leading to inefficiencies and potential damage to electrical equipment if not managed properly. It is essential to understand harmonics in power quality analysis as they can significantly impact systems, especially in industries reliant on sensitive electronic equipment.

The other types of voltages mentioned do not fit the definition of multiples of the base frequency. Variable voltages refer to fluctuating voltages that are not necessarily harmonics. Fundamental voltages are the primary components at the base frequency alone. Residual voltages refer to voltage that remains in a circuit or component after a circuit is turned off and doesn't relate to harmonics or multiples of the fundamental frequency.