Harmonics in an electrical context are sinusoidal components of a signal occurring at frequencies multiple of the fundamental frequency. The fundamental frequency is the main frequency of a periodic signal and is usually the frequency at which an electrical system is designed to operate. Harmonics can be the result of disturbances or distortions in the waveform of the electrical signal. They are represented by integer multiples of the fundamental frequency. Harmonics can cause several problems in an electrical system, including: 1. Heating and energy losses: Harmonics increase the effective current and voltage in an electrical system, thus causing increased energy losses and heating in cables, transformers and other equipment. 2. Waveform distortion: Harmonics can distort the signal waveform, causing a non-sinusoidal voltage. This distortion can affect the operation of sensitive devices, such as computers, and cause overheating or faults in electrical equipment 3. Electromagnetic interference: Harmonics can generate electromagnetic fields that can interfere with other electronic devices, causing electromagnetic compatibility (EMC) problems. 4. Transformer overheating: Harmonics can cause overheating in transformers, reducing their service life and efficiency. 5. Equipment malfunctions: Harmonics can affect the operation of electrical equipment and motors, leading to sub-optimal operation, lower efficiency and more frequent failures. To address these problems, it is often necessary to use filters, power factor correction capacitors and other devices to eliminate or reduce harmonics in electrical systems. Standards and technical guidelines set acceptable limits for harmonics in distribution systems and provide guidelines for handling harmonics to ensure a high quality power supply.