Study On Fualt Line Selection Of Small Current Grounding System Based On Chaos And Identification Of Complex Systems

Electrical energy is becoming an integral energy and power failure prevention andtimely exclude also become particularly important. China’s power supply system for thesmall current grounding system would cause great inconvenience to users within thenetwork when the single-phase ground fault occurs. The impact of load changes,electromagnetic interference, grounding resistance point of failure can not be determinedfactors increase the difficulty of troubleshooting. Combined mathematical theory andeffective algorithm for single-phase ground zero sequence current analysis and find thedifferences between the fault line and non-fault circuit characteristic quantities are alsobeginning to receive attention.This article focuses on the effective selection of the neutral point by the arcsuppression coil grounding system single-phase ground fault occurs, the fault line. Normalsystem operation status and fault running state gives the main factors to affect the resultsof the select line and laid the foundation for the subsequent chapters expand.The basic theory of EMD (Empirical Mode Decomposition) and its application insinusoidal signal were expounded systematically. Sine-aliasing problems encountered inthe application of the method were put forward and the solution in the analysis was given.Signal superimposed sine simulation of the improved method is applied to verify thefeasibility and effectiveness of the method is given. The Duffing time around theorydifficult to detect weak signals after decomposing zero sequence current signal applied tothe method of fault line selection analysis given by the theory of the game against thesubsystem. First line selection scheme is proposed by the combination of EMD and theDuffing oscillator detection theory.As the power signal is very complicated, difficult to obtain the required informationdirectly from the signal. This article proposes a complex system identification method, thefirst current signal is converted to useful symbolic model, and then through the applicationof the theory of ε machine, trying to reveal the status information implicit in the observedsignals, to build out the implicit system state recognition of time series reflect the specific model. Effective recognition of the state of the system parameters through statisticalcomplexity and the number of states, and then elect a fault line.Theoretical analysis by ATP-EMTP power system simulation software to build amodel of small current grounding system will extract the zero-sequence current signalsinto matlab signal processing format. First current signal through the system based onEMD and Duffing time around, qualitative analysis, comparing the phase diagram changesthe fault line. Ε machine theory-based quantitative analysis, the symbols of the transform,the system zero sequence current after causal state reconstruction algorithm processing,obtained by statistical complexity, the number of states and other parameters constitute acomprehensive line selection criterion.