在基于行波自然频率的输电线路单端故障定位方法中,主自然频率值的准确度是进行故障点精确定位的关键。目前的主自然频率的提取大多采用小波变换、MUSIC方法,小波分析受所选小波基影响较大,MUSIC的参数选择对频谱估计影响较大,它们都未能很好地解决这一问题。提出一种基于故障线路自然频率的单端测距新方法。该方法在提取主自然频率过程中首先对行波信号进行EEMD分解,并用ICA方法进行正交化处理,从而抑制WVD本身存在交叉项的问题,然后对各个分量进行WVD转换并叠加,获得正交的自然频率谱;进而综合考虑基波和多次谐波求取全局主自然频率。EMTDC仿真实验验证了该算法在不同故障类型、故障距离、过渡电阻和噪声情况下的可行性及其精度。
In the single terminal fault locating method of transmission line based on traveling wave natural frequency, the accuracy of extracting primary natural frequency is the key to caring out to pinpoint trouble spots in. Currently, wavelet transform and MUSIC method are commonly used for extracting primary natural frequency. Wavelet analysis is influenced by the selected wavelets and the parameters' selection greatly impacts spectral estimation in MUSIC, which can't solve this problem well. A new single ended fault location method of extracting faulted line natural frequencies is described. The traveling wave signal is decomposed by EEMD and orthogonal process is made with ICA method to suppress the WVD's problem of cross-term, and then each component of WVD is converted and superimposed to obtain the natural frequency spectrum orthogonal. Then the global primary natural frequency is obtained considering the fundamental and harmonics. Simulation experiment by EMTDC confirms the feasibility and accuracy of the proposed algorithm under different fault types, fault distance, transition resistance and noise situation.