Electrical Safety for Surface and Underground Mining

Global mining operations have long used resistance-grounded power systems for portable and fixed medium-voltage and low-voltage applications. Control of ground-fault current and the capability to restrict the touch potential on portable and mobile equipment are among the reasons for using resistance grounding in mines. Ground-fault tripping is most often used in ore extraction areas, while in refining and processing areas, alarm-only systems are often selected for their ability to improve continuity of service. Bender offers grounding systems and relays including ground-fault and neutral-grounding resistor monitors and ground-continuity monitoring devices.

Bender roots in mining run deep and the need for insulation monitoring devices in those systems are still vast. The iso685 insulation monitor has many uses in mining applications, from monitoring the DC field in dragline MG sets to monitoring the ungrounded outputs on sophisticated medium voltage AC drives.

In addition to the iso685 for ungrounded systems or circuits, Bender offers many products which can be used in a mine’s grounded power systems, including the popular NGRM500 and NGRM700 neutral grounding resistor monitors. These are often used in conjunction with RC48C ground-fault and ground continuity monitors which detect faults in trailing cables and their connected loads. Integrated product solutions, such as high-resistance grounding systems that communicate site conditions over a data network (locally and remotely) can provide timely information for remote staff and provide enhanced safety at remote sites.

Electrical safety for battery operated vehicles in mines

Products such as the IsoEV425 insulation monitoring interrupter ensure that the electric vehicle’s high voltage battery packs remain isolated from the frame of the vehicle. These devices constantly monitor for insulation breakdown and provide valuable read outs in terms of ohms. Various communication protocols can be used to relay the insulation status to the vehicle’s central processing system. Bender also employs similar safety circuits on DC fast charging stations to protect personnel and equipment from high voltage hazards and break downs. Here, insulation monitors check once again for insulation breakdowns and also for hazardous leakage currents in the ever changing EV charging landscape. The trend is moving towards higher voltages and amperages to decrease charging time, bringing higher demands on materials and safety for personnel.