Research On Technology Of Power Cable Fault Warning And Localization

With the increasingly widespread use of cables, the power sector is facing increasing pressure to diagnose cable fault.Power cable fault warning and location is not only a new requirement of cable fault diagnosis technology in the new situation, but also the future development trend. This paper reviews the status of cable fault diagnosis technology, and then studied cable fault intelligent early warning strategy and fault loocation method based on travelling wave. The main contents of this paper are:The fuzzy theory in the power cable fault warning method was used to solve the problem that the single cable fault warning technology based on insulation is still immature and unreliable. Firstly, a three-layer cable fault warning indicator system, containing target layer, feature layer, index layer is established. Then a fuzzy comprehensive warning model including complex weights on cable fault is proposed, and a cable safety warning process is designed. When testing with the instance data, the results of the model is consistent with the actual situation, and can provide a reference for cable fault warning decisons.The basic principle of traveling waves are described, the general solution of voltage, current traveling wave in the distribution parameters model of cable is given. The dispersion effects and the phenomenon of electromagnetic coupling during the traveling wave propagates in the cable lines are discussed. And the three-phase line Sagami transformation is given. At last, the principles of calibration algorithm based on wavelet transform and Hilbert-Huang transform are compared to get several conclusion, and then simulations are taken to prove it.To solve the problem that the uncertainty of velocity reduces the accuracy of fault location in existing traveling wave fault bcation method, a double-terminal fault location method without velocity is proposed by analyzing the traveling wave propagation in cable lines. The simulation results show that the precisfon of this method is higher than the traditional double-terminal traveling wave fault location method, and the wave head location method based on HHT can help to promote the precision of the method. This method has a good prospect of engineering application.