Studying the Quality of Electric Power at a Tunneling Machine During the Construction of the Underground System

The authors review the problems associated with assuring the quality of electric power in the power supply system of a tunneling machine (TM) for shield rotor drive upgrade by replacing the soft-start system of the electric motors of hydraulic pumps with a frequency-controlled electric drive of the planetary gear. The authors developed a model of a power supply system and researched the quality of electricity in the electrical complex of the TM. Some regularities were found in the impact of frequency converters on the quality of electric power when filter-compensating devices (FCD) are used. Besides, frequency converters have a mutual influence on the total coefficient of harmonic voltage components in each block of electric motors. The authors recommend accounting for potential resonant processes and performing the required settings of the electric drive control system if FCDs are introduced during the upgrade of the machine.