| With the development of energy system,more and more UHV and long-distance transmission lines are available.It is imperative to solve the following problems: reducing the workload after the fault line,reducing the time required to check the fault,saving a lot of manpower and material resources,improving the reliability of power supply,reducing the time of failure and power outage and strengthening and improving the management of system operation.After the system failure,it is necessary to find the fault point quickly and accurately,so it is urgent to locate the fault point accurately.The fault location is carried out by the combination of traveling wave method and wavelet transform.The mode maximum method in wavelet transform is used to detect the traveling wave head of the bus at both ends generated by the fault point.Then,the distance between the corresponding fault and one end is calculated by using the calculation formula in the two end traveling wave method.Based on the step-by-step parameter model,the fault location simulation based on wavelet transform is carried out for different faults at different distances and the same distance under the same fault.It is proved that the fault location of wavelet transform can meet the basic positioning requirements,but there are some errors.In view of the problem of low accuracy of traveling wave fault location in wavelet transform,Hilbert Huang and traveling wave method are selected to locate the fault.Hilbert Huang can be more suitable for the analysis of non-stationary nonlinear traveling waves,overcome the shortcomings that wavelet is only suitable for nonstationary signals,and intuitively and adaptively response wave head arrival.Finally,the Hilbert Huang fault location simulation is carried out with the same fault distance and fault type as wavelet transform.It is proved that Hilbert Huang transform has higher positioning accuracy and meets the requirements of fault location at present stage when combined with traveling wave method. |
