基于Duffing振子的直流系统接地故障检测新方法

从直流系统接地故障的原理出发,在低频注入法的基础上,为弥补低频注入法的固有缺陷,针对对地电容和谐波干扰对故障检测影响大的传统难题,提出了Duffing振子的直流系统接地故障检测新方法.先以双Hilbert变换去除检测特征量中的直流分量,再以lyapunov指数、相图和时域图作为判据,判定系统发生相变时的状态;由相变条件求得故障特征量的幅值和相位,得到接地电阻值,判定接地支路.该方法与小波检测法相比具有稳健性好、精度高,抗干扰性能强的优点,仿真结果证明了该方法的有效性.

A New Method of DC System Grounding Fault Detection Based on Duffing Oscillator

The paper presents a new fault detection method of the Duffing DC system grounding based on the DC system grounding fault principle and the low-frequency injection method in order to make up for inherent defects of the low-frequency injection method and solve the traditional problems of the ground capacitance and harmonic interference on fault detection.In order to determine the system state of the phase transition,the DC component of detection characteristic quantities should be removed by the double Hilbert transform,and a criterion made by lyapunov index,the phase diagram and time domain graph.Grounding resistance can be obtained and the ground slip can be determined according to the amount of fault feature value and phase obtained by the phase change conditions.Advantages are shown such as high stability,high precision,strong anti-interference performance when compared with the wavelet detection method.Simulation results show the effectiveness of the method.