Study On Single-Phase Earth Fault Line Selection Of Underground Coal Mine Distribution Network Based On Hilbert-Huang Transform

Coal mine cable fault has been a technical problem, the normal operation of the mine cable is a necessary condition of safe production, the single-phase earth fault is the highest frequency of the line-fault of the distribution power supply system under the mine, possibly leading the supply system's tripping and influence the regular operation of ventilator when the line fault cannot be found immediately and accurately, not only the fault have serious impact on the safe operation under the mine, but also on the personal property of workers. Then the fault will lead to much various fault, damage the production equipment or causing a fire in severe case. So mine high voltage power supply system requires the ability to accurately determine the fault on the line and cut off the fault line. The mine high voltage power supply system belongs to a small current grounding system, little differences of the steady current amplitude are existed in the each line after the single-phase earth fault, so only identifing the fault line with current amplitude is very difficult.Because the big differences of the transient characteristic quantity are existed between the regular line and the fault line, the distribution power supply system of mine equivalent calculating model of single-phase ground is established in this paper, especially analyzes the transient process of each line during the fault, trying to find the transient characteristic quantity which is used in indicating and identifing the fault. Through analyzing a large number of the related theories and research results in the transient process, the article on zero-sequence current fault lines and sound lines were Hilbert Huang Transform, Phase angle information is the amplitude and the phase angle curve graph, and the fault line defines the validity of the weights, the use of the sample points to determine the fault lines, and is defined by the accuracy of determination of the weight as much as the probability of the fault line. The article also studied the effects of different circumstances grounding resistance and fault phase angle of the proposed fault line selection method, the simulation results show that the effect results from a ground fault line selection and fault resistance phase angle, line selection results with high accuracy, avoid the neural network and particle swarm optimization is easy to fall into the defect minimum value.