Identifying the efficiency decrease factor of motors working under power harmornic in 660V electric mining grids

Abstract

Purpose. Identify the motors efficiency decrease factor corresponding to various values of load-carrying ratio. Methods. Basing on the onsite measurements of power harmonic in 660V low voltage (LV) grids in Vietnam underground mines, simulations have been done on MATLAB and compared with mathematical models. Verifying data will be implemented in Lab-measurements carried out on pumping system to reveal series of decreasing factors. Findings. Series factors present the relation of the level of power total harmonic distortion (THD) and the decrease in motor efficiency with alternative load-carrying ratio. The factors will help mine operators to have better understanding of the power harmonics impact on 660V motors. Originality. The proposed factors and simulation in MATLAB may be applied to all underground mining grids with diffe-rent input parameters of THD. Practical implications. The research is implemented to identify the factors obtained from the operation of motors which work in high power harmonic environment. The resulting factors could be utilized to recalculate mining efficiency.