Harmonics refer to voltage or current components whose frequencies are integer multiples of the fundamental frequency. In power systems, the fundamental frequency is generally 50Hz or 60Hz, so the harmonic frequency is an integer multiple of 50Hz or 60Hz. The generation of harmonic voltage and harmonic current mainly comes from nonlinear loads, such as arc furnaces, inverters, electronic equipment, etc. These nonlinear loads will cause voltage and current distortion and generate harmonic components.

1. Filters can be used to suppress harmonics. A filter is a circuit that can selectively pass or block signals in a specific frequency band. By properly configuring the filter, the propagation and diffusion of harmonic voltages and currents can be effectively suppressed.

2. Harmonic suppressors can be used to reduce harmonics. A harmonic suppressor is a device that can generate harmonic currents that are opposite in phase to the harmonics, and reduce the harmonic level by superimposing and canceling the harmonics with the harmonic currents.
3. Suitable power equipment can be used to reduce the generation of harmonics. For example, the use of low-harmonic motors, transformers and other equipment can effectively reduce the harmonic level.
4. Harmonic problems can be avoided through reasonable grid planning and design. For example, the reasonable configuration of the capacity and number of power equipment to reduce the load rate of the grid can reduce the generation and propagation of harmonics.

Harmonic voltages and harmonic currents are common problems in power systems, which will have an adverse effect on power equipment and grid operation. In order to reduce the impact of harmonics, we can control harmonics through filters, harmonic suppressors, suitable power equipment and reasonable grid planning, etc. This can ensure the normal operation of the power system, improve power quality, reduce equipment damage and electromagnetic interference, ensure the accuracy of power metering, and also protect the environment and the safety and stability of other electronic equipment.