Geographic information system (GIS) terminal cable fault on-line location method

Abstract

The invention discloses a geographic information system (GIS) terminal cable fault on-line location method. The GIS terminal cable fault on-line location method comprises the steps of synchronously acquiring fault current travelling wave signals of three-phase sheaths at two ends of a GIS terminal cable, filtering white noise, pulse noise and high-frequency oscillation noise which are acquired in the fault current travelling wave signals, eliminating outer modulus interference signals and inner modulus interference signals in filtered fault current travelling wave signals, obtaining sampling point sequences corresponding to catastrophe points of the fault current travelling wave signals, identifying the fault current travelling wave signals and performing location according to identified results. The GIS terminal cable fault on-line location method has high applicability, reliability, practical applicability and automation level, and the accuracy of fault location can meet the requirement of underground power cable system fault location.

Description

technical field [0001] The invention relates to the technical field of cable fault detection, in particular to a GIS terminal cable fault online ranging method. Background technique [0002] Considering the construction cost and operation and maintenance cost of urban substations, GIS (Gas Insulated Switchgear, Gas Insulated Switchgear) devices are widely used in urban power grids, and the number of cable lines terminated by GIS is also increasing. On the one hand, the traditional offline ranging method has defects such as long power failure time and the need for special testing instruments; on the other hand, since GIS has no exposed conductor parts, in order to apply voltage for offline fault location, it is necessary to untie the cable terminal. It will affect the advantages of GIS maintenance-free, maintenance-free, safe and reliable, and will also bring new problems due to disassembly and assembly of cable terminals. [0003] At present, there are mainly two types of o...

AI Technical Summary

Problems solved by technology

On the one hand, the traditional offline ranging method has defects such as long power failure time and the need for special testing instruments; on the other hand, since GIS has no exposed conductor parts, in order to apply voltage for offline fault location, it is necessary to untie the cable terminal. It will affect the advantages of GIS maintenance-free, maintenance-free, safe and reliable, and it will also bring new problems due to disassembly and assembly of cable terminals

[0003] At present, there are mainly two types of online distance measurement for power cables: impedance method and traveling wave method. However, the online distance measurement of GIS terminal cables has the following problems: it is difficult to install a suitable traveling wave signal transmission device in the GIS terminal; there are complex electromagnetic fields in the production site. There are more white noise and pulse noise in the collected traveling wave signal; the strong coupling between the currents of the conductors of the cable makes the current of each conductor have more complex modulus interference; the fault traveling wave is at the fault point, protection Complicated catadioptric phenomena will occur at the impedance mismatch points such as the crossover interconnection point of the sleeve, the direct grounding point of the sheath, the busbar and the adjacent busbar, and the traveling wave component in the collected signal is very complicated; when the incoming and outgoing lines of the busbars on both sides of the cable in the production site When the fault is less than 3, the initial traveling wave mutation of the fault is small, and the use of wavelet analysis method to detect the mutation point may fail; the positioning error of the existing ranging algorithm is relatively large, and its main sources include traveling wave velocity, GPS timing accuracy, sampling frequency and Traveling wave dispersion and many other aspects

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