Distribution line single-phase break line judgment and positioning method based on line voltage vector criterion

Abstract

The invention discloses a distribution line single-phase break line judgment and positioning method based on a line voltage vector criterion. The distribution line single-phase break line judgment and positioning method comprises the following steps: step A, acquiring and counting three-phase line voltage; step B, verifying the three-phase line voltage vector; step C, judging a break line fault; step D, outputting the judgment result; step E, positioning the break line fault section. The distribution line single-phase break line judgment and positioning method disclosed by the invention has the following benefits: 1. the voltage vector is used as the parameter for judging the break line fault and is a little influenced by the three-phase load change situation, so that the break line fault can be normally recognized under the situations of no-load, light load, heavy load and three-phase load imbalance of the line; 2. the three-phase mains voltage fluctuation is low in influence; 3. the range of surveillance is wide, and a break line monitoring device can accurately judge and recognize the single-phase break line of the line from the mounting position to a line power supply; 4. the break line monitoring device is convenient to mount and implement and is mounted by a parallel connection method, and the existing three-phase voltage transformer on the line can be directly used as a voltage measurement input device.

Description

technical field [0001] The invention relates to the technical field of grid electric power, in particular to a method for judging and locating a single-phase disconnection of a distribution line based on a line voltage vector criterion. Background technique [0002] At present, most of the overhead line disconnection fault judgment methods are to judge the line disconnection based on the current amplitude, phase and the relative relationship between the amplitude changes between phases, such as the patent application number (201310247895.4) which is applicable to The disconnection alarm device of 6~35kV distribution network, its principle and characteristics are: measure and compare the amplitude and phase of the A-phase and C-phase current of the main line and the branch line of the distribution line, so as to determine the disconnection phase; used for judging One-phase disconnection fault on the rear side of the measurement point (that is, away from the power supply side)...

AI Technical Summary

Problems solved by technology

[0003] The disadvantage is that the precondition of the above judgment method is that the three-phase circuit is required to be completely symmetrical. However, when a phase disconnection occurs in the actual operating grid, the changes in the magnitude of the three-phase current are not necessarily obvious, so it is easy to cause misjudgment.

It is easy to misjudgment when the line is empty-loaded, light-loaded, or unbalanced three-phase load, and it is impossible to normally identify disconnection faults under heavy loads, fluctuations in three-phase loads, single-phase load equipment (such as: single-phase distribution transformers) Power fluctuations caused by switching may lead to frequent misjudgments

Special current transformer equipment must be installed at the measurement point on the distribution network circuit to collect three-phase current, and the installation of the device is inconvenient

Images