Overhead distribution line zero-sequence current acquisition terminal and method based on clock synchronization

Abstract

The invention discloses an overhead power distribution line zero-sequence current acquisition terminal and method based on clock synchronization, including a current sampling terminal arranged on a three-phase line, a voltage transformer and a data receiver connected to the three-phase line, and a voltage transformer It is connected with the data receiver, and the current sampling terminal is connected with the data receiver through a wireless signal; it includes the following specific steps: handshake communication between the data receiver and the current sampling terminal; clock synchronization between the data receiver and the current sampling terminal; The sampling terminal performs phase current sampling processing and uploads it to the data receiver; the data receiver receives the current data collected by the current sampling terminal and judges whether there is an overcurrent or short circuit fault, and performs corresponding processing according to the judgment result; it can be completed at low cost The high-speed sampling of the zero-sequence current of the overhead line provides the most accurate grounding current signal for the distribution network automation system, and can quickly locate the fault when a single-phase grounding occurs in the small current grounding system.

Description

technical field [0001] The invention relates to the technical field of electric power system intelligence, in particular to an overhead power distribution line zero-sequence current acquisition terminal and method based on clock synchronization. Background technique [0002] For reasons of cost and maintenance workload, the power distribution network of most countries in the world adopts a small current grounding system. That is: the neutral point of the transformer in the central substation is not grounded or grounded through the arc suppression coil. When single-phase grounding occurs, the grounding current is very small, which will not cause damage to equipment due to high current flow; when single-phase grounding occurs, the distribution network can still work for 2 to 24 hours with illness. [0003] When the single-phase is grounded, due to the small fault current, it is difficult to select the fault line. Conventional substations rely on the insulation monitoring devi...

AI Technical Summary

Problems solved by technology

[0009] Since the overhead line is not protected by insulating materials, it is difficult to obtain the zero-sequence current by adding the three-phase current, resulting in the ground fault sampling of the distribution network cannot be accurately obtained. When a ground fault occurs, the fault area can only be verified by manually pulling the switch, that is Time-consuming and affects power supply reliability

[0010] By installing a zero-sequence transformer on the switch (circuit breaker) on the overhead line column, although the zero-sequence current can be obtained accurately, due to the high cost and difficult installation, it cannot be widely promoted, and it still cannot effectively solve the problem of zero-sequence current sampling.

[0011] Due to the limitation of insulation distance, installation method, cost and other factors, the overhead line of distribution network cannot accurately obtain the zero-sequence current in the line, resulting in the inability to quickly locate the fault when single-phase grounding occurs

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