Submarine cable fault ranging system and method based on optical fiber pulse transmission

Abstract

The invention relates to the technical field of the power cable monitoring, more specifically relates to a submarine cable fault ranging system and method based on optical fiber pulse transmission. The submarine cable is close to a first terminal and a first grounding line is connected with a host; the submarine cable is close to a second terminal and a second grounding line is connected with a slave; the host is connected with a server, and the host communicates with the slave through a communication optical fiber; a pulse transmission optical fiber for sending square wave pulse to the host is connected between the host and the slave; when the submarine cable is in breakdown, a breakdown point produces first fault travelling wave pulse to transmit to the host, and the second fault traveling wave pulse to transmit to the slave; the slave sends the square wave pulse after detecting the second fault traveling wave pulse, and the square wave pulse is transmitted to the host through the pulse transmission optical fiber. The host disclosed by the invention realize the online ranging according to the detected time difference between the first fault travelling wave pulse and the square wave pulse, and the square wave pulse detected by the host is delayed, the system testing dead zone is solved, and the full-length range and high-precision fault ranging of the submarine cable is realized.

Description

technical field [0001] The invention relates to the technical field of power cable monitoring, and more particularly, to a submarine cable fault distance measurement system and method based on optical fiber pulse transmission. Background technique [0002] Submarine cables are an important part of the construction of cross-sea networking projects, and play an important role in realizing the internationalization of power grids and the interconnection of regional power grids. In recent years, with the improvement of the economic level, the demand for electric energy on islands and land is increasing. Many areas of the national power grid have been constructed and a large number of submarine cables and offshore wind power are under construction. In terms of submarine cable operation and maintenance, problems are more prominent due to the lack of relevant technical standards and instruments and equipment in the high-precision monitoring and testing of submarine cables, as well a...

AI Technical Summary

Problems solved by technology

[0003] At present, the status monitoring of submarine cables is mainly for circulation and temperature measurement, which can only detect the circulation and temperature of the cable operating state, but cannot give early warning of fault locations; submarine disturbance monitoring can give early warning of fault locations, but due to poor signal pattern recognition processing, resistance to The interference is poor, resulting in a high false alarm rate of disturbance monitoring, which causes great interference to maintenance work; there are distributed installations of traveling wave ranging terminals on transmission lines, and a terminal is installed every 10 to 20km to collect fault current traveling waves and apply GPS time synchronization, transmits signals to the main station through the 4G network, and judges the fault distance through the main station. The time resolution is more than a few microseconds, and the ranging error is more than a few hundred meters to several thousand meters. The test accuracy is low and the cost is high. However, some high-voltage cable terminals stand underground, and the signal shielding cannot receive GPS signals at all, which makes this method unusable; there is a Chinese patent CN201210297818.5 that connects the first terminal and the second terminal to measure distance through optical fibers, and the resolution is at the nanosecond level. It can meet the precision requirements, but designing a high-resolution synchronous clock is technically difficult and costly and difficult to promote

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