| 摘要 |
<p>A device for monitoring an electrical cable (2) composed of a conductor surrounded by insulation, to locate insulation defects, while a signal is impressed on the conductor, in the presence of noise fields, the device including an ion generator (4) for creating an ionized atmosphere to envelop the cable (2), a sense wire assembly (6,8) arranged to be disposed in the vicinity of the cable (2) and within the ionized atmosphere so that the signal impressed on the cable (2) conductor is coupled into the sense wire assembly (6,8) when the ionized atmosphere envelops an insulation defect, and a circuit (18,24,30) for monitoring the signal coupled into the sense wire assembly (6,8) from the cable (2) conductor. The sense wire assembly (6,8) is composed of a first wire (8) presenting a low resistance to the ionized atmosphere, a second wire (6) presenting a high resistance to the ionized atmosphere, and a circuit unit (12,14) connected for producing a sense wire signal which is a function of the difference between the signal coupled into the first wire (8) and the signal coupled into the second wire (6). The device may further include a reference conductor (10) arranged to extend along, and in a fixed position relative to, the cable (2), a signal generator (20) connected for applying an alternating reference signal to the reference conductor (10), a signal detector (26) connected for producing a correction signal representative of the degree of resistive coupling of the reference signal into the first sense wire (8), and a correction circuit (34) connected for correcting the signal produced by the monitoring circuit (18,24,30) as a function of the value of the correction signal.</p> |
