High-resistance grounding fault detection method based on flexible DC distribution network

Abstract

The invention discloses a high-resistance grounding fault detection method based on a flexible DC distribution network. The high-resistance grounding fault detection method comprises the steps of: firstly, extracting a feature model IMF1 component of a transient zero-mode current by adopting a complementary ensemble empirical mode decomposition algorithm, performing first-order differentiate operation on the IMF1to obtain a sudden change singular point, calculating a cumulative slope sum in the vicinity of the singular point, and distinguishing a faulty state and a normal state through comparing a slope sum value with a starting threshold value; and secondly, adopting a Prony algorithm for carrying out parameter identification on the IMF1 component to obtain a feature frequency component and a direct current component in the IMF1 component, calculating an energy ratio of the feature frequency component to the direct current component, and further distinguishing different states according to the difference of the energy ratio numerical values. Compared with the existing methods, the high-resistance grounding fault detection method can adapt to accurate feature extraction under a strong noise environment, has the advantages of self-adaptability, convenient application and high detection precision in the feature extraction process, can determine the operating state of the distribution network system incisively, and increases the calculation speed.

Description

technical field [0001] The invention belongs to the technical field of power grid fault detection, and in particular relates to a high-resistance grounding fault detection method of a flexible DC distribution network. Background technique [0002] Recently, the number of DC loads is increasing day by day. When using the traditional AC power distribution system to realize the consumption of distributed energy and the power supply of DC loads, a large number of power electronic converter equipment is required, and the investment cost is greatly increased. On the contrary, if the consumption of distributed energy and the power supply of DC loads are carried out through the DC power distribution system, a large amount of converter equipment can be saved and investment costs can be reduced. In addition to the advantages in terms of economy, compared with the traditional AC power distribution system, the advantages of the DC power distribution system are also reflected in: improvi...

AI Technical Summary

Problems solved by technology

[0006] 1) High-resistance fault feature extraction: The fixed basis function leads to insufficient feature characterization; the feature extraction process is not adaptive. Although the EMD algorithm is adaptive, it is prone to problems such as mode aliasing and endpoint effects; unclear meaning

[0007] 2) High-impedance fault detection criterion: the start-up criterion of the existing HIF detection method is not sensitive, and the distribution network system is misjudged to be in a normal state; the start-up criterion and the discrimination criterion are not constructed separately, resulting in low HIF detection accuracy ; Computationally complex, and most criterion constructions have no physical meaning

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