Cable sheath fault monitoring device and method based on broadcast synchronization signals of multiple Rogowski coils

Abstract

The invention relates to a cable sheath fault monitoring device and method based on broadcast synchronization signals of multiple Rogowski coils. The method comprises the following steps of: 1, setting the primary-secondary transformation ratios of Rogowski coils in a grounding current acquisition sensor and a cable load acquisition sensor to be less than or equal to 1000: 1; 2, installing the grounding current acquisition sensor at the direct grounding position or the cross interconnection grounding position of each monitored line, and installing the cable load acquisition sensor on a cable body; 3, detecting a grounding current and a cable load current, respectively transmitting the grounding current and the cable load current to each monitoring host for signal processing, and transmitting the results to a server through a communication module; 4, when it is judged that a pulse load comes from the grounding circulation signal, enabling the hosts to broadcast control signals, and enabling all the monitoring hosts to collect the control signals at the same time within a preset time to make the synchronization error within 0.1 s; and 5, analyzing and processing the signals monitoredby the plurality of hosts, and predicting whether a fault occurs or not.

Description

technical field [0001] The invention relates to the field of on-line monitoring of electric power system cables, in particular to a Rogowski coil-based on-line monitoring method and device for grounding circulation of a cable sheath. Background technique [0002] According to the statistical results of cable tests, 58% of cable faults occur due to damage to the outer sheath due to external force damage. The metal sheath of a single-core XLPE cable must be reliably grounded at one point during operation. The outer sheath of the power cable will be chemically corroded or physically damaged after violent laying or long-term operation, which will cause insulation damage, thereby exposing the metal sheath and causing metal sheath damage. With multi-point grounding, the circulating current on the metal sheath increases significantly at this time. By monitoring the metal sheath circulation and its variation in real time, the on-line monitoring of multi-point grounding faults in th...

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Problems solved by technology

[0004] (1) The secondary output terminal of the current-type CT sensor can only be short-circuited and cannot be open-circuited. The increase in the resistance of the secondary terminal due to the needs of the circuit system or circuit failure will lead to an increase in the secondary suspension voltage and cause harm;

[0005] (2) The current-type CT sensor uses ferrite as the magnetic core. The larger the transformation ratio, the higher the required output power, and the larger the volume of the magnetic core, resulting in a larger sensor quality, which is difficult to install and easy to cause damage to the grounding wire;

[0006] (3) The current-type CT sensors used in the ground circulation system are all open-type design. If the installation is not in place, the sensor will leak magnetic flux, and the sensor will attract and vibrate to generate noise, and the open-type design is difficult to realize the waterproof and rust-proof of the sensor. Suitable for long-term use in harsh environments;

[0007] (4) The current-type CT sensor has a large volume and a single shape, which cannot be installed in a monitoring environment with a small space, and has high requirements for application conditions

[0008] Therefore, such ground circulation sensors greatly limit the application scenarios of sheath circulation monitoring

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