| 摘要 |
Improved transmission line voltage breakdown strength is achieved by applying magnetic fields in transmission lines. In colinear transmission lines, particularly coaxial cables, one means of magnetic field introduction is accomplished by applying an axial magnetic field about the transmission line, which together with the self-induced power current magnetic field creates a net helical magnetic field whose pitch is dependent upon the relative magnitudes of the azimuthal component of the self-induced magnetic field and the axial component of the applied magnetic field. The applied magnetic field may be achieved by a permanent field or by directing either an alternating current or direct current through a helical winding defining a solenoid coaxial with the transmission cable. Alternatively, the applied field may be achieved by surrounding the grounded sheath with oriented ferrite or other magnetic material in a suitable support medium such as a pliable plastic bond form to produce a multipole magnetic field.
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