What is harmonics issues in AC and DC grid?

In AC and DC grids, harmonics refer to the presence of frequency components that are integer multiples of the fundamental frequency. Harmonics can be problematic because they can cause various issues such as:

Voltage and Current Distortion: Harmonics in the grid can distort the shape of the voltage and current waveforms, resulting in distorted sine waves. This distortion can lead to increased heating of electrical equipment, reduced power quality, and increased losses in the system.

Overloading: Harmonics can lead to increased current flow in the electrical system. This increased current can overload transformers, capacitors, and other equipment, potentially leading to equipment failure and reduced system reliability.

Resonance: Harmonics can cause system resonance, which occurs when the natural frequency of the system matches the frequency of the harmonics. Resonance can lead to excessive voltage and current levels, equipment damage, and even system instability.

Interference with Communication Systems: Harmonics can interfere with communication systems, such as telecommunication lines and control systems. The harmonic frequencies can overlap with the communication frequencies, causing data errors and communication breakdowns.

Power Quality Issues: Harmonics can affect the overall power quality of the grid, leading to flickering lights, damaged sensitive equipment, and malfunctions in motor drives and other electronic devices.

To mitigate the harmonics issues, various measures can be taken, including the use of harmonic filters, active power filters, and the implementation of standards and regulations for harmonic control. These measures aim to reduce the distortion caused by harmonics, enhance power quality, and ensure reliable operation of the electrical systems.

What are the solutions?

At low voltage side, we can use Active Harmonic Filter to compensate the harmonics

At medium voltage side, we can use Statcom or Passive Filter(FC) to compensate the harmonics.