Three-phase hybrid power supply network fault location method based on traveling waves

Abstract

The invention discloses a three-phase hybrid power supply network fault location method based on traveling waves. The method comprises the following steps of enabling a detection device to collect fault voltage information; judging the fault type of the power distribution network, and calculating zero-mode components of the three-phase line and the single-phase power distribution line if the faulttype is a C-phase earth fault; performing HHT conversion on the zero-mode component to obtain a time difference reaching the detection devices at the two ends of the line; and calculating a fault distance through the zero-mode component. According to the scheme of the invention, the transmission speeds of different mode components in phase-mode transformation are different, a mode component transmission time difference relationship is constructed according to line topology parameters, fault branch judgment is carried out, traveling wave distance measurement of multi-modulus time difference isconstructed, fault distance measurement is carried out by using a double-end method principle, the problem that asymmetric fault distance measurement is difficult in a distribution network includinga single-phase distribution branch is solved.

Description

technical field [0001] The invention belongs to the technical field of power grid fault detection, and in particular relates to a traveling wave-based three-phase hybrid power supply network fault ranging method. Background technique [0002] my country's distribution network is mostly a non-effective neutral point grounding system. Single-phase ground faults account for about 80% of all faults. If single-phase faults cannot be eliminated in time, it is likely to further develop into two-phase grounding or even three-phase grounding fault . Accurately locating the fault point has been a research hotspot for scholars for a long time. As an effective method, traveling wave method has been gradually applied in distribution network. [0003] The traveling wave method can be divided into single-ended method and double-ended method in principle. The traditional single-ended method uses the time difference between the arrival time of the initial traveling wave head of the fault a...

AI Technical Summary

Problems solved by technology

Due to the many branches of the distribution network, the cost of using double-ended traveling waves for distance measurement is high, and it is difficult to achieve full network coverage in engineering. To solve this problem, the existing technology also proposes to use distribution transformers to transmit and change traveling waves to solve traveling wave fault location The problem that the signal at the end of the middle line is not easy to obtain can also achieve the purpose of using the double-ended method for ranging

Due to the asymmetry of the line, only two-phase traveling wave or three-phase traveling wave information cannot be used for accurate distance measurement

At present, there are few researches on ranging technology for complex distribution networks with single-phase distribution branches. Therefore, it is urgent to find a ranging method that can adapt to mixed lines.

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