A method is described for examining a propagative medium, such as a signal transmission cable, that requires the acquisition and examination of a minimum number of data points to determine the presence of an anomaly in the medium When an anomaly is detected, its characteristics, such as location, type and amount of loss are determined The characteristics are then displayed If the anomaly is a reflectionless loss, the region containing the anomaly is examined repetitively to determine its location and to improve the accuracy of its location measurement With each successive level of examination, additional samples are collected within the region The new samples are combined with the existing samples to reduce random noise in the data Through this method the location of the anomaly is re-determined with greater accuracy

Method of detecting and characterizing anomalies in a propagative medium

Apparatus for detecting and locating a fault in an electric cable or cable installation using a pulse-echo or impulse current technique comprises a low voltage pulse generator for injecting a series of pulses into a cable or cable installation; a digital store and memory for recording a predetermined number of pulses and for digitizing and storing the waveforms obtained under two different conditions of the cable; means for terminating the recording of pulses a predetermined time after a fault condition is detected; and means for retrieving the signals obtained under the two separate conditions, comparing them and thus locating the position of the fault

Apparatus for locating faults in electric cables

A high-voltage transformer-rectifier device comprising a step-up three-phase transformer with a spatial magnetic circuit made up of three vertical stacks (7) of closed cores (9) insulated from one another and secured in an insulating frame (8), having a common window and carrying the sections (10) of a secondary winding (2). A primary winding (1) comprises three flat rectangular coils (11) whose vertical parts are arranged to lie pairwise along the axis of the common window in each stack (7) of the cores (9). A bridge rectifier section comprises individual bridge rectifiers connected to the sections (10) of the secondary winding (2), and each of the potential screens is formed by ring sections (6 and 20) arranged one on top of another along the stacks (7) of the cores (9).

High-voltage transformer-rectifier device

A hybrid circuit breaker for interrupting a fault current in an electrical circuit line having a line impedance, the hybrid circuit breaker including a mechanical circuit breaker adapted to interrupt the line upon detecting the fault current, a semiconductor device arranged in parallel with the mechanical circuit breaker to conduct the fault current when the mechanical circuit breaker is disconnected, a branch connected between the electrical circuit line and ground, the branch including an impedance unit and a control unit configured, upon detecting the fault current, to connect the impedance unit in parallel with the line impedance.

Hybrid Circuit Breaker

A method and apparatus for detecting fluid level in a tank in the vicinity of a transmission line (1), the fluid level being such as to cause reflection of a signal transmitted along the transmission line. The method includes the steps of: a) transmitting a signal along the transmission line; b) monitoring the transmission line for any reflections of the signal; c) generating an analysis window of time (t 1 , t 2 , t 3 ) if the magnitude of a given characteristic of the reflected signal is greater than a predetermined threshold value; and d) analyzing the reflected signal received during the period of an analysis window to provide the required information on the fluid level.

Method and apparatus for determining a fluid level in the vicinity of a transmission line

The invention relates to a combined current and voltage converter for metal-enclosed high-voltage installations with compressed-gas filling. In order to be able to avoid any passages for the connecting leads through the housing (1, 2), the electrode of the capacitive voltage converter part consists of an intermediate element (3) inserted into the housing in an insulated and gas pressure-tight manner. The intermediate element (3) has on its outside a layer of insulating material (9) and on top of this a metal layer (10). The whole (3, 9, 10) forms a support body for current converter cores (11) surrounded by secondary windings. The low-voltage capacity between the intermediate element (3) and the metal layer (10) is fed to an electronic measuring amplifier (14) via a screened measuring cable (12/12a). The current converter cores (11) are protected mechanically by a sheath tube (16), the latter simultaneously conducting housing currents. FIG. 1.

Combined current and voltage converter for a compressed-gas insulated metal-enclosed high voltage installation

To locate faults in electrical lines (9, 10) by means of the pulse echo method, two pulse echo curves (3) of structurally identical lines are compared, one curve having been recorded by a faultless line and the other curve having been recorded from a line with a fault (F) to be found by means of a pulse echo measuring instrument (1) and stored by means of a signal storage device (15). To be independent of the specialist knowledge of an expert in the evaluation of curves, an evaluating device is specified which synchronously compares the two pulse echo curves to be compared or, respectively, the signal voltages and/or the time delays of these signal voltages, derived from these curves. In dependence on the signals to be compared exceeding predeterminable limit values, an error signal is generated, the transit time of the transmitted pulse from the start (A) of the line to the fault location (F) is determined and the fault distance (1F) is calculated and indicated. The width of the transmitted pulses (16) is preferably less than 2 ns, and the voltage used is lower than 60 V. The method specified is also suitable for fault location on high-voltage tubular gas-filled lines.

Fehlerortung auf elektrischen leitungen

Short-circuit limiting device

Transformer for transmitting pulses or power at stepped high-voltage potential

In order to avoid taking leads through the envelope (1, 2) the electrode of the voltage transforming capacitive part comprises an intermediate piece (3) insulated and tight to the pressure gas, inserted in the envelope. This piece comprises, outwardly, an insulating material coating (9) and a metal layer (10) on said coating. The three (3, 9, 10) form a support for the current transforming cores (11) wound with the secondary winding. The low voltage between the intermediate piece (3) and the metal layer (10) is led by an armoured measuring able (12/12a) of an electronic measuring amplifier (14). The current transforming cores (11) are mechanically protected by a cylindrical screen which, at the same time, leads the envelope currents.

Hans Hartmann

Papers

Combined current and voltage converter for a compressed-gas insulated metal-enclosed high voltage installation

Fehlerortung auf elektrischen leitungen

Short-circuit limiting device

Transformer for transmitting pulses or power at stepped high-voltage potential

Combined current and voltage transformers for a high voltage installation enclosed in a metal envelope filled with pressure gas