![[ Visit Client Website ]](images/banner.gif)
Monday, March 15, 2010: 10:35 AM
214 B (Henry B. Gonzales Convention Center)
An electrical substation copper grounding system has suffered a severe corrosion rate due to the presence of DC stray current, coming from an aluminum plant. A study was done to demonstrate the presence of unsteady DC stray current as the source of the copper corrosion.
To decrease the influence of the DC stray current over the copper grounding system and to facilitate the application of cathodic protection, the electrical substation grounding mat was disconnected from the aluminum plant grounding mat and reconnected through Polarization Cell Replacement (PCR) devices.
Since the DC stray current could not be disconnected to measure structure to soil true potentials, three different types of IR drop free test stations were designed and installed.
To protect the substation grounding mat from corrosion, three impressed current distributed groundbed systems were installed and adjusted. To ensure the copper grounding system was protected a polarization potential criterion of at least -300 mV with respect to a Cu/CuSO4 was used.
To decrease the influence of the DC stray current over the copper grounding system and to facilitate the application of cathodic protection, the electrical substation grounding mat was disconnected from the aluminum plant grounding mat and reconnected through Polarization Cell Replacement (PCR) devices.
Since the DC stray current could not be disconnected to measure structure to soil true potentials, three different types of IR drop free test stations were designed and installed.
To protect the substation grounding mat from corrosion, three impressed current distributed groundbed systems were installed and adjusted. To ensure the copper grounding system was protected a polarization potential criterion of at least -300 mV with respect to a Cu/CuSO4 was used.