Energy conservation with sodium cables

Technical Report · Thu Jan 01 00:00:00 EST 1976

OSTI ID:7304171

The safe, reliable, economic and convenient use of energy conserving sodium cables on U.S. electric utility systems is discussed. The economic merit of various conductor metals is defined in terms of the conductance (conductivity x conductor cross-sectional area) that can be purchased per dollar. At current metal prices, the dollar will buy one unit of conductance in copper, 2.6 units in aluminum, and 8.7 units in sodium. By the use of Kelvin's Law it is shown that the optimum aluminum conductor would nominally operate near 60/sup 0/C and the optimum sodium conductor between 40 and 50/sup 0/C. For optimum sodium and aluminum conductor sizes, the sodium metal saves nearly half the energy wasted in conductor heating. It also produces a significant reduction in the cost of transmitting electricity. In a number of worked examples in the 15, 35, and 138 kV voltage classes, Joule heating conductor losses are compared in overhead lines, 90, 75, and 60/sup 0/C aluminum conductor underground lines, and 50/sup 0/C sodium conductor underground lines. The results are used to determine the total transmission cost in terms of three components: (1) installed line cost; (2) installed cost of the generating capacity needed to meet the peak line loss; and (3) cost of the dissipated energy at 50 percent cable load factor. In the most widely used 15 kV voltage class, but even at 138 kV, the sodium cable can economically compete with conventional overhead lines provided all energy related charges are taken into account.

• Research Organization: Underground Power Corp., Weston, MA (USA)
• OSTI ID: 7304171
• Report Number(s): NP-22213
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
24 POWER TRANSMISSION AND DISTRIBUTION
ELECTRIC CABLES
ECONOMICS
ENERGY CONSERVATION
HVAC SYSTEMS
ALUMINIUM
COMPARATIVE EVALUATIONS
COPPER
ENERGY LOSSES
FABRICATION
PERFORMANCE
POWER TRANSMISSION LINES
RESOURCE CONSERVATION
SODIUM
UNDERGROUND POWER TRANSMISSION
USES
AC SYSTEMS
ALKALI METALS
CABLES
CONDUCTOR DEVICES
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
METALS
POWER SYSTEMS
POWER TRANSMISSION
TRANSITION ELEMENTS
320303* - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Equipment & Processes
200301 - Power Transmission & Distribution- AC Systems
EHV & UHV- (-1989)