Corrosion of the concentric neutrals of buried URD cables. Final report

Technical Report · Wed May 01 04:00:00 EDT 1985

OSTI ID:5322558

Hennessey, M G; Prime, Jr, J B; Compton, K G; Valdes, J G; Burns, J G

The corrosion of the wire concentric neutrals on buried URD cable has been studied in a test plot in South Florida. The backfill was a combination of sand and muck to give a resistivity of about 2500 ohm. cm. Various wires were used for the neutrals, some wires and cables received impressed ac current, other received no impressed current, thus making a good spectrum of actual practice. It was found that ac shifted the potential to earth of the neutrals, both negatively and positively, depending upon the ac current density, thus creating long corrosion cells. A threshold of ac current density was found, above which corrosion was greatly accelerated, at 1.5 mA/cm/sup 2/ in the soil used in this test. This confirms similar thresholds found by others (37 and 38). Simple cable to earth potential measurements did not reveal the presence of corrosion. A historical review of the subject of ac corrosion and its mechanism is given. AC is shown as a clearly significant factor in the corrosion of concentric neutrals of buried URD cable in the soils of the FPL Test Plot.

• Research Organization: Florida Power and Light Co., Miami (USA)
• OSTI ID: 5322558
• Report Number(s): EPRI-EL-4042; ON: TI85920822
• Country of Publication: United States
• Language: English

Related Subjects

200301* -- Power Transmission & Distribution-- AC Systems
EHV & UHV-- (-1989)
24 POWER TRANSMISSION AND DISTRIBUTION
ALTERNATING CURRENT
CABLES
CHEMICAL REACTIONS
CONDUCTOR DEVICES
CORROSION
CURRENT DENSITY
CURRENTS
ELECTRIC CABLES
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
EQUIPMENT
POWER DISTRIBUTION SYSTEMS
POWER TRANSMISSION
SOILS
UNDERGROUND POWER TRANSMISSION