The Design Of Selective Leakage Protection Device Integrated Mine Power System

Non-ground neutral system(NUS) is commonly used in underground power grid, leakage protection is one of the important factors of underground security. On the basis of theoretical analysis about the steady state and transient fault of the leakage of underground power grid, by comparing the advantages and disadvantages of existing leakage protection methods, this paper find out a kind of two-level fusion algorithm based on the temporary stabilization information selective leakage protection method.The first step in fusion line selection method was to analysis the transient waveform of the zero sequence current with wavelet, the decomposition level was ten. Due to there was a lot of d8 waveform semaphore, we could calculate the difference between the d8 waveform of each branch by the signal distance method and transferred the result to the probability event between [0,1] without considering it as the dependent basis. The next step was to choose three kinds of line seletion methods of steady state criterion based on the fuzzy theory. The measurement of failure was constructed with amplitude of zero sequence method, zero sequence fundamental wave phase method and zero sequence method of reactive power, the consequence was between [0,1], then the primary fusion line selection was performed. If the selection was good, electric leakage protection was executed directly. Otherwise, step 3 was taken. The third step was to construct the identification framework of the line selection targets of the branches and bus and build basis functions of the line selection criterion of the transient and steady state, and the information fusion was executed to implement the secondary fusion by D-S theory. After the simulation, this line selection method was good to solve some without the effection of the leakage angle, and certified the effectiveness in case of that one criterion did not work.This paper introduced a machine for electric leakage protection with DSP as the control centre based on the steady state information fusion line selection algorithm. The hardware and DGUS screen was selected. The operation interface was designed with DGUS. At the same time, the insulation resistance Test was selected to implement the leakage block.Last, we set up a simulation grid leakage experiment platform of mine in the laboratory, by changing different leakage resistance, on grid insulation resistance testing, we fie the experimental data with the theoretical curve together, the error less than 3%. In this paper, we set different way, different leakage branch, collection zero sequence voltage and zero sequence current data, adopt fusion algorithm, by using the fusion algorithm, the fault branch after fusion increased about 5%~20% more than the single criterion in the basic reliability distribution function, and the non-fault branch obviously decreased, verified the reliability of the prototype, in addition we made the control time within 0.05 s, then it can achive fast protection.