Powering Mobile Mining Machines: DC Versus AC Power

To achieve higher profitability, an important objective in mining applications is to minimize the cost per ton of material moved, which leads to the use of more efficient mining machines and systems. Among open-cut excavating machines, preference is often given to electric draglines and rope shovels due to their high productivity and efficiency. Since they are the biggest machines in a mine, any efficiency improvements to their electric systems would result in significant energy savings. The dc distribution has been historically known as an effective method of power delivery. Due to recent developments in power electronics, dc distribution systems are now being seriously considered for various medium-voltage (MV) applications.

DC on the Upswing

AC power has been widely used in both generation and transmission due to the ease of stepping up and stepping down voltage by means of transformers. Various aspects of ac power, such as load flow, harmonics, transients stability, and efficiency, have been extensively studied, and solutions to the existing issues have been developed. AC power standards are well known to both equipment manufacturers and end users. Consequently, ac power is the default option for most industrial applications.