Research On Fault Location Method Of Cable Network With Different Characteristic Impedance Branches

Cable is an important carrier of information transmission and energy distribution,which is widely used in power system and communication.Therefore,fault location of cable network plays an extremely important role in ensuring the safe and stable operation of the system.In practical engineering application,the complex and diverse cable network structure brings some challenges to fault location.In order to improve the simplicity and versatility of fault location method,a fault location method based on transmission parameters is proposed in this paper.The method is simple and effective,and is not affected by the characteristic impedance of each branch in the network,which can realize fault location of cable network with different characteristic impedance branches.The main research results of this paper are as follows:(1)Based on transmission parameters,a method for measuring the length of each branch in cable network is proposed.First,the cable model and the calculation method of distributed parameter are introduced and the limitation of the method based on scattering parameters is analyzed.And the potential of transmission parameters in cable length measurement is demonstrated.Using the transmission line theory and mathematical method,the analytical formulas for length measurement are derived,which are not affected by characteristic impedance values in network.Then a two-node cable network with different impedance branches is taken as an example to verify the accuracy and effectiveness of the length measurement method.(2)Based on the length measurement formulas,the fault location method of cable network is proposed.First,the basic principle of fault location of cable network based on transmission parameters is introduced.Combined with the specific network structure and fault type,the specific steps of fault location are described in detail.Three typical fault cable networks are selected as simulation examples to sho w the process of fault location and verify the validity of the fault location method in this paper.(3)RG-58 and RG-59 cables are selected to carry out length measurement and fault location experiments,and error analysis is carried out.Experimental results show that the proposed method is accurate and reliable,and the positioning accuracy is not affected by characteristic impedance,terminal load and fault impedance.Meanwhile,on the basis of theory and experiments,a fault location system of cable network is designed by using MATLAB,so that the method presented in this paper can be popularized and applied in practical projects.