Application of EMD and Duffing Oscillator to Fault Line Detection in Un-effectively Grounded System
Tang Baiwen · Proceedings of the CSEE · 2013
Aiming at the characteristics of the un-effectively grounded systems that the zero-sequence current is non-stationary and nonlinear,the approach based on empirical mode decomposition(EMD) and Duffing oscillator detection method was given.EMD method has good adaptivity,and the Duffing system presents a high degree of sensitivity when the external signal’s frequency is the same as that of the driving force.Firstly,the zero-sequence current was decomposed and the first intrinstic mode function was extracted as the amount of the zero-sequence current fault.Then the fifth harmonic component was extracted and put into the Duffing oscillator detecting system.It could be determined by the changes in the system’s phase diagram whether the current line is in fault.Fault simulations in different conditions were given for every line and the experimental results indicated that the method is reliable.