Power Transformers For Optimized Mining Power Systems

The choice of HV/MV transformer short circuit impedance and MV distribution voltage have a major impact in the total cost of mining power systems. Optimized values depend on constraints imposed by starting large MV motors that can often generate unacceptable voltage drops and harmonic distortion. Designs that use HV/MV transformers with low short circuit impedance connected in parallel to minimize voltage drop during MV motor starting results in unnecessarily high short circuit currents that require costly MV switchgear and cables. Power system total cost optimization is an iterative process that is illustrated using a typical mining power system.