Obstacle detection and localization

This first section is devoted entirely to the detection and location of obstacles in transmission lines. Whether transmitting low-amplitude analog signals, digital signals or electrical energy, lines can be subjected to a variety of stresses that can momentarily or permanently impair their function. As a general rule, such damage takes the form of a conductor break or short-circuit. In other cases, the deterioration in line operation may be more gradual, with the appearance of a localized fault in an undetermined longitudinal position. Deterioration of the primary insulation following the initiation of an electric arc is the most typical example of an event which, sooner or later, can interrupt signal or power transmission. Experience shows that this type of anomaly very often manifests itself by the establishment of a resistance R _d between...