Sodium Conductors Research Articles

Insulated Sodium Conductors

The development and characterization of a new polyethylene insulated sodium conductor are described. The resistivity, specific gravity, and cost of sodium are compared to corresponding properties of copper and aluminum. While the alkali and alkaline earth metals have relatively good electrical conductivity, sodium was chosen because of its light weight, low cost, and availability. Physical properties of the polyethylene insulated sodium conductor were determined. Potential areas of question, such as service life, reaction of water with damaged cables, and combustion characteristics are covered in detail.

Field Trials on 15-kV and 600-Volt Sodium Cable

The use of sodium conductor cable presents an opportunity for reduction in cost of cable for underground residential distribution systems. In order to evaluate its usage a direct buried test installation was made involving both 15-kV and 600-volt sodium cable. Testing the 15-kV cables consisted in load cycling, short-circuit faulting, and fault location tests. After the completion of tests on the 15-kV sodium cable, a service installation was made in a rural area west of Chicago. Load cycle tests were also made on the 600-volt sodium cable. This included an overload which resulted in the failure of the cable at the terminal. Insulation damage tests were made to determine the corrosive properties of the conductor. Fault locating tests made on the 600-volt cable, as on the 15-kV cable, showed that presently available equipment should be adequate.

Evaluation of Sodium Conductor Power Cable

The suitability of the newly developed polyethylene- insulated sodium conductor for use in electrical power cables was evaluated electrically and mechanically. Polyethylene-insulated sodium conductors are shown to lend themselves to a wide range of constructions manufactured on standard cable-fabricating equipment. Because of the plastic nature of metallic sodium, neither conductor stranding, nor helical assembly in the case of multi- conductor cables, is required for flexibility.

Insulated sodium conductorsߞa future trend

Polyethylene-insulated sodium conductors, having economic advantages over conventional conductors, have been developed. The sodium conductors are light in weight and can be manufactured on standard cable-fabricating equipment. The light weight and the usual flexibility of the sodium cable should afford greater ease of installation in direct-buried and overhead power cable applications. Extensive tests indicate that this system is tough and resilient, and can withstand considerable abuse. Sodium's electrical conductivity ranks just below copper and aluminum. A useful service life of 40 years, under normal ambient conditions, is predicted for direct-buried cable.