Incomplete-penetration hysteresis losses in transmission line cables

Autor: Lawrence Dresner
Rok vydání: 1998
Předmět:
Zdroj: Physica C: Superconductivity. 310:213-217
ISSN: 0921-4534
DOI: 10.1016/s0921-4534(98)00464-x
Popis: At 77 K, the resistivity of ceramic, high-temperature superconductors grows gradually rather than sharply with increasing current. The critical-state theory of hysteresis losses therefore needs to be modified. This has been done for slab conductors whose resistivity can be taken proportional to a power of the current density. Simple formulas have been derived in the limiting cases of incomplete penetration and full penetration when the losses are driven either by a sinusoidal transport current or a sinusoidal external magnetic field. These formulas can be applied to multilayer transmission line cables once the current distribution within and among the layers has been determined. This distribution has been calculated (in the incomplete penetration limit) by solving Maxwell's field equations. A formula is presented for the dependence of the hysteresis loss on winding angle. The formula is used to determine the optimum winding angle.
Databáze: OpenAIRE