Research On Fast Detection Technology Of Short Circuit Current In Electrical Power System

With the continuous development of UHV and UHV technologies in China,the voltage levels of power systems and distribution capacity have been increasing.But at the same time,large-scale power system short-circuit faults also occur frequently,short-circuit fault current generated by short circuit will seriously affect the normal operation of the entire power system,therefore,the detection of short-circuit fault current must be fast,accurate.At present,the existing methods of detecting short-circuit fault current have certain defects in both of these aspects,and the vast majority of studies on short-circuit current detection only stay in detecting the occurrence of a fault without further amplifying the short-circuit fault current Value of the size of the effective assessment of the magnitude of the short-circuit fault current in the verification of electrical equipment stability and electrical wiring design and so has an important role,so for short-circuit fault current rapid detection should be divided into two parts: First,Can quickly detect the occurrence of a short circuit fault,and secondly,can quickly detect the magnitude of the short circuit fault current,which is also the main research focus of this article.The main contents of this paper are divided into the following sections:(1)Analysis of the power system short-circuit fault and short-circuit current hazards on the power system,and to clarify the need for rapid detection of short-circuit current.(2)Analysis and study of the existing short-circuit fault current detection methods: including hardware method,software method,after introducing two kinds of hardware method testing,the software testing algorithm Fourier transform method,Walsh function method and Kalman filter Depth discussions on the current testing methods to summarize the problems.(3)Introduce the theory of wavelet transform,the wavelet transform signal singularity detection principle applied to the short-circuit fault current detection process,which involves the basic theory of wavelet transform,wavelet function selection,and through the singularity theory to add And then distinguish short-circuit fault and other operating conditions,the simulation test shows that the detection speed is far superior to the traditional detection methods.(4)In the problem of amplitude detection of short-circuit fault current,multi-resolution analysis in wavelet transform and MALLAT tower algorithm are applied flexibly in the detection process.This process is also a problem that has not been involved in previous studies,and further use of simulation Experiments show the effectiveness of the proposed theory.The new method proposed in this paper can not only quickly detect the occurrence of short-circuit current in the power system,but also obtain the amplitude of the short-circuit current,which lays a good foundation for subsequent relay protection work.