High-voltage cable fault on-line monitoring method for constructing novel criterion based on sheath current

Abstract

The invention discloses a high-voltage cable fault on-line monitoring method for constructing a novel criterion based on sheath current. The method comprises the following steps of measuring the amplitude and phase of grounding current of a metal sheath in a direct grounding box at the head and tail ends of a crossed and interconnected main section of a cable, and constructing a new characteristic quantity according to the ratio of the amplitude and phase of the grounding current at the head and tail ends of the same metal sheath loop and the absolute value of the phase difference of the grounding current at the head and tail ends of different metal sheath loops, establishing a characteristic quantity matrix corresponding to a fault criterion according to multi-dimensional characteristic fusion, and adjusting corresponding parameters in the characteristic quantity matrix by using historical data of various faults of a certain high-voltage cable so as to provide a set of fault diagnosis and positioning standards suitable for the high-voltage cable.

Description

Technical field[0001]The present invention relates to a high-voltage cable fault online monitoring method based on the construction of a protective current constructing a new type of criterion, which is suitable for a voltage level of 110kV and above, which belongs to the field of electricity technology.Background technique[0002]As the size of the output and electricity grid is accelerated year by year, the high-voltage cable is increasingly increasing by the advantages of the transmission requirements for high-capacity electrical energy and protecting the urban appearance. Therefore, timely understand the operating state of the cable, ensure that high-voltage cables work a crucial role in the safety and stability of the power system.[0003]The high voltage cable generally refers to a single core cable operated at a voltage level 110kV and or more. The main insulating outer layer of the single core cable has a wire metal guard layer as a shielding layer. When the current flows over t...

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Problems solved by technology

For example, establish the equivalent model of the cable cross-connection grounding system, use the equivalent model to analyze the corresponding circuit model under different fault conditions, and realize the cable fault detection by simulating the circuit model and analyzing the change of the corresponding characteristic quantity under different fault conditions. Online monitoring; there are also intelligent algorithms such as support vector machine, logistic regression, decision tree, k-nearest neighbor, artificial neural network, naive Bayesian and integrated learning to carry out model training on existing feature parameter samples, and adjust model parameters through sample training , to obtain a set of more accurate characteristic parameters to realize the online monitoring of cable faults, but different algorithms have their own shortcomings, some are difficult to solve the problem of large data samples; some need to spend a lot of time and memory; The independence of the feature quantity is required to be high

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