High-voltage cable metal outer sheath grounding loop current on-line monitoring system

Abstract

The invention discloses a high-voltage cable metal outer sheath grounding loop current on-line monitoring system, and solves the technical problem that a power cable cannot be effectively detected inreal time. The high-voltage cable metal outer sheath grounding loop current on-line monitoring system comprises a front-end remote terminal unit and an integrated monitoring center server, and the front-end remote terminal unit and the integrated monitoring center server establish wireless communication connection with each other through a global system for mobile communication (GSM), code division multiple access (CDMA) or general packet radio service (GPRS). Compared with the prior art, the high-voltage cable metal outer sheath grounding loop current on-line monitoring system is advantaged in that the amplitude and variable quantity of the loop current of each cross-connect subsection of an operating high-voltage cable metal outer sheath is monitored in real time, valid data is remotelytransmitted to the integrated monitoring center server for statistics, analysis and warning, on-line real-time monitoring of a high-voltage cable metal sheath multipoint grounding fault is achieved, manpower is effectively saved, the working efficiency is improved, fault risks are discovered early, power failure frequency is reduced, and the high voltage power cable can reliably operate.

Description

technical field [0001] The invention relates to a cable monitoring system, in particular to a system for monitoring the performance of power cables. Background technique [0002] With the rapid development of power grid construction, the use of high-voltage power cables (cables) is becoming more and more widespread, and there will be more and more demands for performance monitoring of new cables and historical data collection of cables that have been laid. At the same time, the cables laid earlier are being used. As the service life increases, the insulation problems of the cables will appear and increase. Therefore, it is necessary to monitor the performance of the cables. [0003] Under normal use conditions, there is a certain induced electromotive force between the metal sheath of the cable and the cable core. In the event of an accident, internal overvoltage in the power system or lightning strike, the induced electromotive force is particularly serious. Therefore, the...

AI Technical Summary

Problems solved by technology

The power cable structure above 66KV is mostly a single-core cable. If the two ends of the metal sheath are connected to each other and then grounded directly, when the cable core passes current, due to the electromagnetic induction of the current in the cable core conductor, the metal sheath will be generated. Induced voltage causes induced circulation on the metal sheath, which will increase the operating temperature of the cable, resulting in power loss, directly affecting the transmission capacity of the cable and accelerating the aging of the cable

[0004] There are still the following problems in the long-term operation of power cables: (1) Electrical deterioration, thermal deterioration, chemical deterioration, and mechanical deterioration occur, and they may also be bitten by rats and insects, and the metal sheath may cause The metal sheath is grounded at multiple points, forming a loop between the metal sheath, grounding wire and the grounding system, resulting in ground circulation. If the current of the ground circulation rises to a very dangerous value, 50-90% of the transmitted current will cause metal The sheath or the armor layer of the cable heats up, and even breaks down the weak insulation

When the power cable is damaged by external force, the wrong connection of the cross-interconnection system, the grounding wire is stolen, termite bites, and chemical corrosion, the grounding current value will be abnormal, which will cause the local temperature of the cable to rise, and accelerate the insulation layer of the cable. Thermal aging will affect the current carrying capacity of the cable line and increase the operating loss of the line. In severe cases, it may cause a single-phase ground fault in the high-voltage cable and stop power supply

(2) The power cable monitoring in the prior art mainly relies on manual regular inspections. Power cables are generally laid in trenches or underground with complex environments. It is very likely that the cables will fail before the next inspection cycle. Cable Operational Requirements

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