Views: 0 Author: Site Editor Publish Time: 2026-10-19 Origin: Site
Analysis of Harmonics in Coal Mine Power Grids
Coal mine power grids have unique characteristics and require power supply that is reliable, safe, technically sound, and economical. Therefore, in addition to ensuring reliability and safety, the power supply system of a coal mine grid must also guarantee power quality. Since harmonics are an important indicator of power quality, the study and control of harmonics in coal mine power grids are particularly important in modern mine power supply systems.
Harmonic Mitigation Measures for Coal Mine Power Grids
Harmonics in power grids exert harmful impacts on the complete power supply network, so harmonic mitigation has become a pressing task requiring immediate attention. Major harmonic reduction methods for power systems are as follows:
Passive mitigation: Carry out modifications to equipment that generates harmonics.
Active mitigation: Fit harmonic mitigation equipment to deal with harmonic-producing loads. The prevailing technologies now include passive filtering, active filtering, and hybrid filtering.
Determining Harmonic Mitigation Solutions for Coal Mine Power Grids
Most coal mine power grids use reactive filter solutions nowadays. However, these devices are vulnerable to variations in system parameters and may trigger resonance. Coupled with coal mine grids’ concentrated high-impact loads that switch frequently, active filters have become the dominant filtering technology for coal mine power systems.
The above test results reveal major harmonic issues on-site: the 6 kV busbar voltage THD and 5th harmonic current exceed permitted limits, and the auxiliary shaft winch produces 5th, 7th, 11th and 13th harmonic currents above the allowed values.
Hence, harmonic reduction for this coal mine grid needs to prioritize the 5th harmonic, with the 11th and 13th harmonics also considered. Given the mine’s large load concentrations and the requirement for prompt, reliable compensation under sudden load surges, active filters (the state-of-the-art mitigation approach) are chosen for this harmonic control scheme.
