Research On Fault Recognition And Location Method Of High Voltage Transmission Line

Short-circuit faults are the most prone to faults in transmission lines,and they are also the faults with the most serious consequences.Therefore,it is of great significance for the stable operation of power system to quickly and accurately identify the fault type and remove it from the power grid.In terms of fault identification,in order to improve the accuracy of short-circuit feature extraction of transmission lines,a feature extraction method combining adaptive noise variational modal decomposition and fuzzy entropy is proposed.The model not only has high accuracy in extracting fault features,but also has good noise robustness.In addition,according to the fault feature classification surface,an improved dragonfly algorithm is also proposed to optimize the transmission line fault identification model of the nuclear extreme learning machine to realize the identification of the short circuit fault of the transmission line.Experiments show that the optimized kernel extreme learning machine is superior to the traditional fault classification model in fault classification,not only improves the recognition speed,but also significantly improves the accuracy.In terms of fault location,in order to improve the positioning accuracy of the existing two-terminal traveling wave method,a two-terminal positioning method for transmission lines based on line mode components is proposed.By analyzing the characteristics of the modulus component in the fault signal of the transmission line,the line modulus component is selected as the characteristic of the fault location.This method improves the disadvantages of the traditional algorithm that needs to know the time when the fault occurs.It only needs to measure the initial moment when the traveling wave reaches the two ends of the line to locate the fault and improve the accuracy of the location.In addition,in order to obtain the precise time when the initial traveling wave head arrives at both ends of the line,the fault signal is analyzed by the combination of LCD and TEO.Experiments show that the model can still accurately extract the fault arrival time under the influence of noise.Finally,through the analysis of the special structure of cable-overhead lines,a fault location method for mixed transmission lines is proposed.By comparing the Pearson coefficient of the fault phase current,the fault location can be determined and the fault location can be located by using the double-ended method.