中文摘要：

基于行波固有频率的故障测距方法不依靠识别行波波头即可进行精确故障测距,测距的关键是正确提取故障行波固有频率的主成分。该方法应用于架空线—电缆混合输电线路时,由于波阻抗不连续,会形成混叠的固有频率频谱,给正确识别和提取故障行波固有频率主成分带来困难。基于此,文中提出一种基于行波固有频率和经验模态分解（EMD）的架空线—电缆混合线路故障测距方法,在提取故障行波固有频率主成分之前先利用EMD进行信号分解,获取故障测距所需的故障行波成分,再对其进行固有频率频谱分析、主成分提取和故障测距计算。对某实际的110kV架空线—电缆混合输电线路的仿真分析表明,该方法可较好地解决现阶段频域方法进行架空线—电缆混合线路故障测距时存在的频谱混叠问题,具有一定的实用价值。

英文摘要：

A fault location method based on natural frequencies can work accurately without identifying the wave front.The key factor of this approach is to correctly extract principal component of the natural frequencies of fault travelling wave.Considering the discontinuous wave impedance,the natural frequencies spectra of mixed overhead-cable lines may be aliased and cause difficulties in identifying and extracting the principal component of natural frequencies.In order to handle this more effectively,a fault location method based on natural frequencies and empirical mode decomposition（EMD）for mixed overhead-cable lines is proposed.By using EMD,a signal can be decomposed to obtain the required part of the travelling wave before extracting the principal component of natural frequencies spectra of travelling wave.The natural frequencies spectra can be analysed subsequently to extract the principal component of natural frequencies spectra of the faulty travelling wave to finally obtain the fault location（s）.Simulation on a 110 kV mixed overhead-cable line system shows that the proposed method can satisfactorily solve the spectra aliasing problem in fault location studies for mixed overhead-cable lines in frequencies domain.It has potential values for practical usage.