Research On Mine Power System Leakage Criterion Based On Data Fusion

Leakage is not only a main fault type of mine low-voltage power grid,but also an important factor affecting power supply safety of industrial and mining enterprises.Because the leakage signal is weak,easily disturbed and the leakage mechanism is complex,the existing leakage protection methods have their own limitations,so the identification of leakage fault in mine power grid has not been well solved.Therefore,it is of great significance to study a criterion of leakage protection for improving the safety of power supply of mine low-voltage power grid.In this article,the instantaneous sequence network model describing the whole process of single-phase leakage of mine low-voltage power grid is established.The mathematical expressions and variation rules of zero-sequence of full current and zero-sequence of full voltage of each line are given by the analysis model,so that the whole process of single-phase leakage of mine low-voltage power grid can be quantitatively estimated.Through theoretical and simulation analysis,it is concluded that the zero-sequence current waveform of fault branch and non-fault branch are quite different after leakage occurs,while the zero-sequence current waveform of non-fault branch is similar.Based on the conclusion,this article applies the complementary transient and steady-state leak detection criteria to the fusion leak detection.In order to facilitate data fusion,the fault measure functions of each selection criterion are defined,and the basic reliability assignment function is constructed by improving the fault measure function.Further,the selection criterion of transient and steady-state fault information fusion based on D-S evidence theory is proposed.The criterion selection and leakage problem is transformed into evidence reasoning problem,which makes the selection and omission turn into a probability event.Compared with 0 and 1(non-fault and fault),the wrong judgement rate is greatly reduced.The simulation results show that the fusion method is suitable for many fault types.In addition,when one of the transient or steady-state leakage criteria is misjudged or missed,the fusion method can still correctly select the leakage.The criterion of leakage protection studied in this article can select fault lines quickly and effectively,and provide reliable protection for power supply safety of mine low-voltage power grid.It has certain theoretical significance and engineering value.