High-resistance ground retrofits in pulp and paper mills

The safety and reliability of low-voltage, high-resistance grounding (HRG) schemes have made them an excellent choice for applications in the pulp, paper and other process industries. As facilities shift toward this technology for reliability in low-voltage substations, retrofitting existing grounded systems becomes the focus of several critical application considerations. This article briefly reviews different grounding methods and their theories of operation. Examples of actual installations are presented that identify potential misapplications of high-resistance ground retrofits. The authors discuss typical ground voltages and currents, and present important considerations for reliable and safe installation of HRG equipment.