Power distribution network fault line selection method using zero-sequence current full quantity Hough transformation

Abstract

The invention relates to a power distribution network fault line selection method using zero-sequence current full quantity Hough transformation and belongs to the technical field of relay protection of an electrical power system. When a single-phase ground fault of a power distribution network occurs, fault zero-sequence current can be obtained according to three-phase current measured at a protective installing position, zero-sequence current data of each feeder of a 1.5ms short time window is extracted, Hough transformation is conducted, an included angle in the direction of overall changes of an overall change trend at a zero-sequence current full quantity initial phase is formed, relation between the zero-sequence current full quantity initial stage change direction of each feeder and the overall change direction is compared, and power distribution network fault line selection is achieved. By means of the method, noise interference resisting performance of the line selection method can be effectively improved, fault feeders under the condition of small fault angles and high-resistance ground faults can be identified, and fault initial transient data loss can not affect the effectiveness of the line selection method. Simultaneously, the method is good in robustness and is not subject to effects of arc faults, non-linear load influence and the like, requirements for hardware sampling speed are greatly reduced, and good practicality is achieved.

Description

technical field [0001] The invention relates to a fault line selection method of a distribution network using full zero-sequence current Hough transformation, and belongs to the technical field of electric power system relay protection. Background technique [0002] When a single-phase ground fault occurs in a distribution network whose neutral point is grounded through an arc-suppression coil, the fault transient current amplitude is much larger than the steady-state current and is not affected by the arc-suppression coil. Compared with the steady-state component, the transient component after the fault has great advantages, making the line selection method based on the transient quantity the first choice for fault line selection. [0003] Most of the line selection methods based on transient quantities are based on the differences between the faulty line and the healthy line in terms of the sudden change direction and amplitude of the transient quantities. These features a...

AI Technical Summary

Problems solved by technology

Distribution network faults are mostly single-phase ground faults, and the problem of line selection has been difficult to solve. The main reasons are: 1. The fault boundary is complex and random, such as the initial phase angle of the fault, the fault distance, and the size of the transition resistance

Different fault conditions, transient zero-sequence signal frequency components, attenuation characteristics, and spectrum energy distribution are quite different; 2. When a single-phase ground fault occurs near the voltage zero-crossing point, the high-frequency components caused are very small, and the high-frequency transient quantity is selected The sensitivity of the line method is greatly reduced; 3. The electrical characteristics of the cable line and the overhead line and the length of each line are quite different, and the similarity between the zero-sequence current waveforms of the sound line becomes worse; 4. Using the traveling wave detection method, the traveling wave propagation speed is relatively low Fast, but the distribution network line is short, and the signal interference of the distribution network is more, it is difficult to capture the first wave head of the traveling wave reliably

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