Electrical Safety for Refining Systems

The large crucibles and vats used in smelting systems are often moved by electric motors with various voltages and currents. Reliable, uninterrupted power is required to prevent the molten metal from solidifying in these containers. The power supply or transformer grounding is often designed ungrounded or resistance grounded. In refining systems, Neutral Grounding Resistor configurations are crucial for managing fault currents and protecting sensitive equipment from potential damage, thereby enhancing system reliability and safety. Bender fault location systems are available for resistance grounded and ungrounded systems to quickly and automatically locate defective power circuits. When using permanent insulation monitoring and insulation fault location systems, the cost of maintaining plants is considerably reduced, and the availability and safety of both plant and personnel are increased significantly. 

The power supply is critical to refining and smelting systems. The medium voltage supplied to the facility is transformed down to 480 V or 600 V and distributed through the facility via electrical cables or busbars, often referred to as branch feeders. It is then either connected to loads or transformed to lower voltages. Depending on the system grounding, either a Bender ISOMETER®s or RCMS residual current monitoring relays (ground-fault monitors) monitor these and help ensure continuous operation. Fault detection is only the first step in troubleshooting. Adding downstream monitors and current sensors can allow for quicker and safer location of ground faults. References mention that approximately 80-95% of the faults in a facility start as a phase-to-ground fault - making this time savings compound the return of investment.