Ground fault line selecting method for small current grounding system

Abstract

The invention provides a ground fault line selecting method for a small current grounding system. The method comprises the steps that a zero sequence voltage transformer and a zero sequence current transformer respectively acquire zero sequence voltage signals and zero sequence current signals when the small current grounding system encounters faults, a secondary voltage transducer and a secondary current transducer convert the zero sequence voltage signals and the zero sequence current signals into measurement signals for fault line reorganization respectively, the measurement signals are processed by a programmable operational amplifier and then are transmitted to an FPGA module, the FPGA module controls an AD sampling module to carry out high-speed synchronous sampling, sampling code stream data obtained through the sampling of the FPGA module are transmitted to an embedded processor in a DMA mode, the embedded processor processes the sampling code stream data, and ground fault line selection detection is carried out. According to the ground fault line selecting method for the small current grounding system, an FPGA is utilized for controlling an AD sampling chip to achieve the high-speed sampling, DAM communication between the embedded processor and the FPGA module is achieved, data throughput capacity is improved, and the embedded processor is made to have more resources for integrated application of judgment logic of various fault line selection algorithms.

Description

technical field [0001] The invention relates to a method in the field of electric power systems, in particular to a ground fault line selection method for a small current grounding system. Background technique [0002] The power system is divided into two types according to the neutral point operation mode: the neutral point effective grounding system and the neutral point non-effective grounding system. The neutral point is directly grounded or grounded through a low-value impedance system, which is called a neutral point effective grounding system or a high-current grounding system; the neutral point is not grounded, grounded through a high-value impedance, or grounded through an arc-suppression coil (arc-suppression reactor) (Resonant grounding), known as neutral point non-effective grounding system or small current grounding system. [0003] In the 6 ~ 66kV distribution network, the small current grounding system is widely used. The advantage of using a small current g...

AI Technical Summary

Problems solved by technology

However, the corresponding problems also follow. Because the fault current is very small when the single-phase grounding of the small current grounding grid is grounded, and the structure of the distribution network is complex and the operation mode is changeable, the fault line selection of the distribution network is subject to many restrictions. Difficulty in fault line selection

Conventional relay protection devices cannot accurately detect fault lines at all, which has led to the problem of line selection for small current single-phase ground faults becoming a technical problem for a long time

At present, some ground fault line methods for small current grounding systems have also been proposed, but these methods generally have certain shortcomings, mainly because of poor fault feature extraction capabilities and single line selection methods.

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