CN-116087689-B - Cable fault detection device and method based on optical fiber synchronization

CN116087689BCN 116087689 BCN116087689 BCN 116087689BCN-116087689-B

Abstract

The invention discloses a cable fault detection device and method based on optical fiber synchronization, which belongs to the technical field of cable fault detection and is used for cable fault detection and positioning, two cable fault positioning detection mechanisms are arranged and connected through optical fibers, wherein the lengths of fault cables and the optical fibers are equal, two ends of the fault cables are respectively connected with fault positioning sensors on the two cable fault positioning detection mechanisms, and the waveform oscillation characteristics of fault signals in the cable are obtained, the anti-interference processing is carried out by carrying out threshold setting through a Schmitt trigger, and the inversion of a NOT gate is carried out, the acquisition card is used for triggering acquisition in advance through the transmission of the TTL, so that the positioning calculation of the acquisition data of two monitoring devices is realized, and the fault position of the fault cable is judged.

Inventors

ZHANG YOUPING
ZHANG XU

Assignees

西安博源电气有限公司

Dates

Publication Date: 20260512
Application Date: 20230220

Claims (5)

1. The cable fault detection device based on optical fiber synchronization is characterized by comprising two cable fault positioning detection mechanisms, wherein the two cable fault positioning detection mechanisms are connected through optical fibers, each cable fault positioning detection mechanism comprises a fault positioning sensor, a signal conditioning plate, an optical fiber synchronous transmitting module, an optical fiber synchronous receiving module and a pre-triggering acquisition card, the fault positioning sensor is electrically connected with the pre-triggering acquisition card, the optical fiber synchronous transmitting module and the optical fiber synchronous receiving module are respectively connected with the signal conditioning plate, and two ends of each optical fiber are respectively connected with the optical fiber synchronous transmitting module and the optical fiber synchronous receiving module; the fault positioning sensor comprises two semicircular manganese-zinc materials, wherein the semicircular manganese-zinc materials are used for unilaterally winding a coil, the coil is output through an integrating circuit, and the coil is electrically connected with the pre-trigger acquisition card; The signal conditioning board comprises a detector circuit, the input end of the detector circuit is connected with the first-stage operational amplifier, the output end of the detector circuit is connected with the SMA connector and is connected with the Schmitt trigger, and the output pin of the Schmitt trigger is connected with the NAND gate.
2. The cable fault detection method based on optical fiber synchronization, which adopts the cable fault detection device based on optical fiber synchronization as claimed in claim 1, is characterized by comprising cable fault points, wherein the lengths of the cable and the optical fiber are equal, and the cable fault detection method comprises the following steps: Connecting two ends of the fault cable with fault positioning sensors on two cable fault positioning detection mechanisms respectively, and acquiring waveform oscillation characteristics of fault signals in the cable; Performing threshold setting through a Schmitt trigger to perform anti-interference processing and inverting an NOT gate; and through the transmission of the TTL of the optical transceiver, the acquisition card pre-triggers the acquisition, realizes the positioning calculation of the acquired data of the two monitoring devices, and judges the fault position of the fault cable.
3. The method for detecting cable faults based on optical fiber synchronization according to claim 2 is characterized in that the anti-interference processing comprises the steps of extracting an envelope signal from waveform oscillation characteristics, adjusting the envelope signal into a TTL signal through a Schmitt trigger to generate a negative pulse signal, and reversing the negative pulse signal into a square wave signal through a 74LSO4 circuit.
4. The method for detecting cable faults based on optical fiber synchronization is characterized in that positioning calculation of collected data of two monitoring devices is performed by transmitting the collected data to an optical fiber conversion module of a cable fault positioning detection mechanism from an optical fiber port through a 232-fiber conversion circuit, extracting TTL signals at a level port of the optical fiber port RX, shorting RX and TX electrical port TTL to form a ring, connecting the TTL signals to a pre-trigger port of an FPGA (field programmable gate array) collection card of the cable fault positioning detection mechanism, and pre-triggering the port at the other end to collect hundreds of microseconds of data in advance when TTL rising edge signals are obtained by the pre-trigger port at the other end, so that fault signal loss is prevented.
5. The method for detecting cable faults based on optical fiber synchronization as claimed in claim 2, wherein the fault location calculation process is as follows, the fault signal acquired by the cable fault location detection mechanism A corresponds to the number N1 of acquisition cards, the fault signal acquired by the cable fault location detection mechanism B corresponds to the number N2 of acquisition cards, the cable length L corresponds to 1/N of time of each point corresponding to the sampling rate of the acquisition card, and the optical fiber module delay time is as follows The time difference between the cable fault location detection mechanism A and the cable fault location detection mechanism B is T0= (N1/N-N2/N- ) The fault signal transmission rate is V, the distance from the fault point to the cable fault location detection mechanism a is L1, and the fault distance l1= (V) 0.01 T0 -L)/2。

Description

Cable fault detection device and method based on optical fiber synchronization Technical Field The invention belongs to the technical field of cable fault detection, is used for cable fault detection and positioning, and particularly relates to a cable fault detection device and method based on optical fiber synchronization. Background With the development of national economy and urban power grid transformation work, a large amount of power cables are adopted for power supply of distribution lines, due to factors such as complexity of laying conditions, influence of daily use environment and the like, faults of the power cables occur, particularly single-phase grounding and two-phase short circuits occur, safe operation of a power system and daily life of people are seriously influenced, even safety accidents are caused, life and property safety of people are endangered, an existing cable fault positioning visual simulation test method, cable fault positioning method, device and system are provided with a patent number (CN 102798802B, CN 115267420A) and are used for improving accuracy and working efficiency of simulation test operation, the visual requirements of the power system which are increasing day by day are met, actual fault positions of the cables can be accurately obtained, and in the actual use process, the technology is relatively dependent on a time synchronization module, two equipment synchronous acquisition is carried out through time synchronization, and requirements on the time synchronization period are relatively high, and single types of faults can be positioned only. Disclosure of Invention The invention aims to provide a cable fault detection device and method based on optical fiber synchronization, which are used for carrying out anti-interference treatment and NOT gate inversion according to waveform oscillation characteristics of fault signals in a cable through a Schmitt trigger, and realizing positioning calculation of collected data of two monitoring devices through transmission of an optical transceiver TTL and pre-trigger collection of a collection card. In order to solve the technical problems, the technical scheme includes that the cable fault detection device based on optical fiber synchronization comprises two cable fault positioning detection mechanisms, the two cable fault positioning detection mechanisms are connected through optical fibers, each cable fault positioning detection mechanism comprises a fault positioning sensor, a signal conditioning plate, an optical fiber synchronous transmitting module, an optical fiber synchronous receiving module and a pre-triggering acquisition card, the fault positioning sensor is electrically connected with the pre-triggering acquisition card, the optical fiber synchronous transmitting module and the optical fiber synchronous receiving module are respectively connected with the signal conditioning plate, and two ends of each optical fiber are respectively connected with the optical fiber synchronous transmitting module and the optical fiber synchronous receiving module. The fault positioning sensor comprises two semicircular manganese-zinc materials, wherein the semicircular manganese-zinc materials are wound on one side to form a coil, the coil is output through an integrating circuit, and the coil is electrically connected with the pre-trigger acquisition card. The signal conditioning board comprises a detector circuit, the input end of the detector circuit is connected with the first-stage operational amplifier, the output end of the detector circuit is connected with the SMA connector and is connected with the Schmitt trigger, and the output pin of the Schmitt trigger is connected with the NAND gate. A cable fault detection method based on optical fiber synchronization, comprising a cable fault point, wherein the cable is equal to the optical fiber in length, and the cable fault detection method comprises the following steps: Connecting two ends of the fault cable with fault positioning sensors on two cable fault positioning detection mechanisms respectively, and acquiring waveform oscillation characteristics of fault signals in the cable; Performing threshold setting through a Schmitt trigger to perform anti-interference processing and inverting an NOT gate; and through the transmission of the TTL of the optical transceiver, the acquisition card pre-triggers the acquisition, realizes the positioning calculation of the acquired data of the two monitoring devices, and judges the fault position of the fault cable. The anti-interference processing comprises the steps of extracting an envelope signal from the waveform oscillation characteristics, adjusting the envelope signal into a TTL signal through a Schmitt trigger to generate a negative pulse signal, and reversing the negative pulse signal into a square wave signal through a 74LSO4 circuit. The positioning calculation of the collected data of the two monitoring devices is as