Measure and Suppression of Harmonic Currents for Heavy-duty Hoisting Machines

The heavy-duty hoisting machines powered by thyristor-controlled converter become the dominating harmonic source in coal mine power supply system. The high-order harmonics will interfere on the triggering angle of control circuit in AC-DC drive system and cause the stall fault of hoisting machines. Based on that, the measurement and analysis of harmonic current are carried out in field, a lot of harmonic current waveforms and practical data are obtained during the operation of hoisting machines. One method to suppress harmonic pollution is adopted by installing passive power filter. The design method and procedure of passive power filter are presented through a practical device. The newly designed filter is installed and applied in field. The results show that the filter can decrease harmonics and improve the power quality obviously. At the same, these heavy-duty hoisting machines run normally since the installation of filter