Fault circuit selection method based on EMD and rough set theory

Abstract

The invention discloses a fault circuit selection method based on EMD and rough set theory. The fault circuit selection method mainly comprises the following steps: I, acquiring zero sequence current of different lines, and decomposing zero sequence current signals within a certain time by using EMD; II, calculating intrinsic mode energy of IMF component of different circuits, the amplitude of first IMF components of different circuits, and comprehensive related coefficients of the first IMF components of different circuits; III, performing knowledge reduction on a sample set after EMD by using the rough set theory, and establishing decision rules, so as to obtain final circuit selection results. By adopting the fault circuit selection method, on the basis of the rough set theory, various types of information after EMD are comprehensively utilized, and the circuit selection efficiency and accuracy can be improved.

Description

technical field [0001] The invention relates to a fault line selection method using EMD and rough set theory, and belongs to the field of fault line selection methods in power system relay protection. Background technique [0002] When a single-phase ground fault occurs in a small current grounding system, if the fault line cannot be found in time and the fault is eliminated, it will bring great harm to the power system. However, due to the weak fault information and external interference, it is difficult to correctly select the fault line. Therefore, the fault line selection problem of the small current grounding system has not been well resolved. [0003] In the prior art, the empirical mode decomposition (EMD) is used to decompose the signal, and then the fault criterion is established by using the natural modal energy, phase, amplitude and other information of the decomposed IMF components to distinguish the faulty line from the non-faulty line . Only using a single c...

AI Technical Summary

Problems solved by technology

[0002] When a single-phase ground fault occurs in a small current grounding system, if the fault line cannot be found in time and the fault is eliminated, it will bring great harm to the power system

However, due to the weak fault information and external interference, it is difficult to correctly select the fault line

Therefore, the fault line selection problem of the small current grounding system has not been well resolved.

Only using a single criterion can easily lead to misjudgment of faulty lines

Using support vector machine, neural network and other algorithms for fusion line selection will easily cause information redundancy and affect the efficiency of line selection

Images