Feed Line Fault Line Selection And Fault Location

Considering the factors of technical economic and security, the non-effectively grounded neutrals are taken in the medium voltage networks in China. The distribution network is the most direct link for the customers, because of its wide range,high probability of single-phase ground fault, the fault line selection and fault location have the unusual points. The fault traveling waves and transient will not affected by the arc suppression coil, while the single-phase ground fault occurs in the distribution networks with the non-effectively grounded neutrals. The fault traveling waves contain the information of the fault feeders and the fault location, so they can be used for fault line selection and fault location. A electromagnetic transient simulation platform with the automatic tracking compensation arc suppression coil grounding neutral is builded, the analyses of electromagnetic transient of the distribution networks are based on it. About the unreal grounded analysis and detection, the necessity of the unreal grounded detection is proposed, and the Mechanism analysis and electromagnetic transient simulation show that, both of them will lead to the voltage rise of the neutral point, but there is a great difference of their envelopes, consequently a method of unreal grounded detection is proposed based on the detection of the envelopes. Under the small initial phase angles, the decaying DC component of the zero-sequence current is very obvious, so there is a great advantage of using it to realize the fault line selection. Under the large initial phase angle, the capacitive transient component of the zero-sequence current is more obvious, so the fault line selection method based on the characteristic frequency band of wavelet coefficients is proposed. Based on the great nonlinear curve fitting capability of the ANN, a fault location method using the energy distribution is proposed by analysising the mapping of the energy distribution and the fault location. At the same time, digging the information of the measured data, the operation distribution network field data, and analysis of field operating conditions of a typical distribution network. The measured waveform to verify the reliability of the fault line selection algorithm. The statistical analysis of measured data and waveform is classified according to different characteristics, to study practical and reliable fault line selection algorithm and research the applicable fault line selection device, these works have a guiding role, to a certain extent,these will promote the utility of the fault line selection algorithm. Aspects of distribution network fault location.for the study of direct distribution line, analysis the mapping between the distribution of transient energy and fault position deeply, with strong nonlinear fitting ability, the paper proposed a intelligent fault location algorithm based on transient spectroscopy.