| 摘要 |
A method, in a high-voltage cable (1) comprising a central conductor (2) consisting of one or more strands (2a), an inner semiconductive layer (3) and a surrounding insulating layer (4), of measuring the topography (3a, 3c, 3d, 3e, 3f, 3g) at the interface between the inner semiconductive layer (3) and the insulating layer (4). A plurality of probes are used, arranged in a fixed array, spatially fixed at the outside of the cable, to emit ultrasound, with a frequency of between 0.1 MHz and 20 MHz, preferably between 0.5 MHz and 5 MHz, in the form of pulses, and to receive (detect) reflected sound (echo). The probes are activated systematically, one at a time, or a few at a time, such that the pulses are emitted from the probes cyclically with a time lag between the pulses, whereas reflected sound is detected in a plurality of, or in all of, the probes. |
