A single-ended ranging method using neutral point switching and the resulting traveling wave injection signal

Abstract

The invention provides a single-ended ranging method using neutral point switching and the resulting traveling wave injection signal, the purpose of which is to solve the single-phase grounding fault location problem of 10-66kV distribution network, 1) conduction connection in the transformer neutral The thyristor at the point generates a high-frequency traveling wave component propagating at a uniform speed on the line, so that the traveling wave propagation of the line mode component system is zero; 2) Record the moment t1 of the thyristor state switching; 3) When the traveling wave reaches the fault point, only Reflection is generated on the fault phase, thereby producing a detectable wave head of the linear mode α traveling wave component; 4) Record the moment t2 when the line mode α traveling wave component arrives at the substation; 5) Calculate the time between the two recorded moments t1 and t2 The time difference t, t is the time for the traveling wave head to propagate to the fault discontinuity point and return to the substation bus after the thyristor switch action of the neutral point, and then use the following formula to determine the fault distance.

Description

technical field [0001] The invention relates to the technical field of electric power automation, to the field of 10-66kV distribution network automation, in particular to a single-end ranging method utilizing neutral point switching and generating traveling wave injection signals therefrom. Background technique [0002] Most distribution networks in my country are non-effectively grounded neutral systems, and single-phase ground faults account for about 80% of all faults. Accurately locating the fault point has been a research hotspot for a long time. As an effective method, traveling wave method has been gradually applied in distribution network. The mixed power transmission of overhead lines and cable lines changes the propagation velocity of traveling waves and the reflectance of distribution networks, making some traveling wave positioning methods no longer effective, and more in-depth analysis is needed. [0003] The traveling wave method can be divided into single-e...

AI Technical Summary

Problems solved by technology

However, there are many catadioptric phenomena in the distribution network, it is difficult to identify reflected traveling waves, and the transmission characteristics of voltage transformers are not high, resulting in low single-ended traveling wave ranging accuracy

Some literatures propose the principle of using zero-mode-line-mode wave velocity difference for positioning, but because the wave velocity difference between zero-mode and line-mode is small, the recognition degree of the wave head is high, so the general analysis methods such as wavelet transform and EMD are accurate. Insufficient sex, resulting in large errors

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