Cable Discharge

Other issues, such as the zero-missing phenomenon, the leading current interruption, and the cable discharge, also stem from the large charging capacities of cables. The effects of these issues on the cable system design are discussed in Section 3.5. The discussion includes countermeasures for the problems and suggestions for equipment selection. 

There are several methods to determine and compare the resistance to partial discharges. Some tests are done on finished cables, such as the U-bend test, and others are done on laboratory samples molded from the insulation, that are subjected to partial discharges created by sharp objects, such as needles under high voltages. The tests compare either the energy required or the length of time required to erode or fail (short circuit) samples of similar thickness. 

Safety Showers. Safety showers and eyewash fountains or hoses should be installed where corrosive or toxic materials are handled. A large-volume, low velocity discharge from directly overhead should effect continuous drenching, ie, a minimum flow of 20 L/min (50 gal /min). Water to outside showers may be heated to a maximum temperature of 27°C by an electric heating cable. The valves for all safety showers should be at the same height and relative position to the shower head, and they should operate in the same way and direction. The shower station should be identified by paint of a bright, contrasting color. In areas where chemicals harmful to the eyes may be encountered, an eyewash fountain or spray should be available in case of splash accidents. 

The severity of corrosion interaction will depend on the density of the stray current discharged at any point on the secondary structure. This may be assessed by measuring the changes in structure/soil potential due to the application of the protection current. Potential tests should be concentrated on the portions of pipe or cable which are close to the structure to be cathodic-ally protected, where the potential change is likely to be more positive. 

Bugna GC, Chanton JP, Cable JE, Burnett WC, Cable PH (1996) The importance of ground water discharge to the methane budgets of near shore and continental shelf waters of the northeastern Gulf of Mexico. Geochim Cosmochim Acta 60 4735-4746... 

Martin JB, Cable JE, Swarzenski PW (2000) Quantification of groundwater discharge and nutrient loading to the Indian River Lagoon. St. Johns River Water Management District Report, Palatka FI Martin J-M, Meybeck M, Pusset M (1978a) Uranium behavior in the Zaire estuary. Netherlands J Sea Res 12 338-344... 

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