A new fault diagnosis method based on damped least square QR-factorization algorithm in grounding grid

With the development of power system and the constant attention to the security of equipment and personnel, fault diagnosis of grounding grid gets more and more attention. In this paper, a new fault diagnosis method for grounding grid based on damped least square QR-factorization algorithm is presented. Firstly, a magnetic field reconstruction method based on the magnetic field method is presented and then a calculation method for magnetic field above grounding grid is proposed. Afterwards, in order to solve the ill-posed reconstruction equations, a damped least squares QR-factorization algorithm is used. Finally, a simulation example is used to verify the feasibility and accuracy of the algorithm. The simulation results show that the reconstructed magnetic field and actual magnetic field are very close; the reconstruction method can also be used when the original data have some errors. So the magnetic field reconstruction method in this paper can be applied to fault diagnosis of grounding grid.