By hvhipot 
Harmonics, electromagnetic interference, and power factor reduction are listed as the three major public hazards in the power system. Therefore, understanding the mechanism, hazards, detection methods, and treatment methods of harmonics is of great significance for ensuring the safe operation of power systems.
Harmonic waveform and current
What are the hazards of harmonics in the power system?
1. Harmonics can cause additional losses to power equipment in the power grid, reducing the efficiency of power generation, transmission, and equipment. A large amount of third harmonic flowing through the centerline can cause overheating of the line and even lead to fires.
2. Harmonics can affect the normal operation of electrical equipment, causing mechanical vibration and noise faults in motors. Local overheating of transformers, overheating of capacitors, cables, and other equipment, aging and deterioration of insulation parts, reduced equipment lifespan, and ultimately damage.
3. Harmonics can cause grid resonance, which may amplify harmonic currents several times or even tens of times, posing a significant threat to the system, especially to series capacitors and reactors. Grid resonance often leads to its combustion.
4. Harmonics can cause misoperation of relay protection and automatic devices, resulting in unnecessary power outages and losses.
5. Harmonics can cause inaccurate electrical measuring instruments, resulting in measurement errors and direct economic losses to power supply departments or power users.
6. Harmonics can cause interference to communication systems near equipment, generate noise, and reduce communication quality. In the worst case, information loss may cause the communication system to malfunction.
7. Harmonics can interfere with the normal operation of electronic devices such as computer systems, leading to data loss or crashes.
8. Harmonics can affect the performance of wireless transmission systems, radar systems, nuclear magnetic resonance equipment, and cause noise interference and image interference.