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Wavefront identification is important for traveling based fault location. In order to improve its reliability, a novel wavefront identification method based on Harris corner detector has been proposed in this paper. The principle of single-ended traveling wave fault location was briefly introduced at first, and the features of wavefronts generated by faults on transmission lines were analyzed. The arrival of traveling waves' wavefronts is considered as corner points in digital image of waveshape. The corner points can be extracted precisely by Harris corner detector, and both false corner points and non-fault caused disturbance can be eliminated according to the calculated distance between two neighbour corner points and the angle of the corner point. The proposed method is proved feasible and effective by digital simulated test.

The network information security vulnerability assessment consists of two kinds of risks. The stable risks of vulnerability itself and the cumulative multi-risks that are generated from a successful attack and which can impact on the whole network. To count cumulative multi-risk, a new method has been developed, which uses vulnerabilities in attack graph and reverse iteration tracing algorithm based on rough sets. Two kinds of cumulative multi-risks will be identified, named ‘the worst state’ and ‘the critical state’. The experimental evidences prove the veracity and validity of the new algorithm model.

Because of the energy crisis and environment deterioration, there is a general consensus about the development of new energy vehicle especially electric vehicle in the world. The development of electric vehicles has brought new challenges to the distribution network. The charging strategy, the location planning of electric vehicle charging stations and sizing, the coordination planning between electric vehicle and the distribution grid depends on the future development scale electric vehicles and charging load forecasting. Because there is a certain distance from commercial operation in china, the prediction theory and method of the electric vehicle development scale and charging load are not mature. By using the method of artificial neural network to establish the development scale and charging load forecasting model of electric vehicle. The model is proved its correctness through an example of the electric vehicle scale and charging load forecasting of Kunming, a big city in West China. The paper provides a new way for future development scale and charging load forecasting to electric vehicle of China.

The IT capability maturity model and its evaluation system is put forward about smart grid which is suitable for China in view of the capability construction. The Extension method is used to establish the IT capability maturity evaluation model of smart grid. The method is simple and practical, easy to operate, easy to realize by computer and it is verified its effectiveness to smart grid through an example of IT capability evaluation with a province-level smart grid enterprise in western China. Key words: smart grid; capability maturity model; Extension method; IT capability

A method is provided to make natural frequency method be applied to single terminal traveling wave fault location in the paper. A group of fault distance suspected is calculated by single terminal method of traveling wave fault location method firstly, then deal with current travelling wave of fault by FFT to get the natural frequency reflecting fault location so that a fault distance can be calculated by it. Contrast the fault distance from natural frequency method and everyone of the group of fault distance suspected from single terminal method of traveling wave fault location method to determine the suspected fault distance closed to it is the calculation results we want. Numerical simulation shows the method can improve effectively the reliability of single terminal traveling wave fault location.

Two results were obtained by analysing electromagnetism transition condition: firstly, when the initial phase angle of fault is larger, the characteristic of travelling wave is obvious, and the polarity of the first travelling wave head is consistent with the overall trend of zero sequence current in preliminary stage; secondly, when the initial phase angle of fault is smaller, the characteristic of travelling wave is not obvious, but the fault lines and perfect lines can be recognized through the direction of decaying direct current component in zero sequence current, and the direction of decaying direct current component is consistent with the overall trend of zero sequence current in preliminary stage. Research suggests that it is feasible to make the overall trend of zero sequence current in preliminary stage as characteristic for line selection.

It is difficult to achieve precise fault location for hybrid transmission line of distribution network, because it has wave impedance discontinuity point. Section location is the premises of precise location. On the basis of others’ research results, the matrix algorithm of distribution network single-phase ground fault section location is improved in the paper. It makes the sparse degree of matrix is higher, computation is less. An algorithm of recovery the network topology only based on the fault description matrix is suggested when the visualization data of a line network topology is loss or the operating is in the non-visual condition. The method is applied to revise fault description matrix, so that the matrix algorithm has some fault-tolerance. The applicability and validity of the improved algorithm was verified by an illustration. The method realizes the fault section location, and the subsequent accurate fault location is presented in this paper.

There is a smoothing reactor and DC filter between the inverter and the direct current line to form a boundary in the HVDC transmission system. Since this boundary presents the stop-band characteristic to the high frequency transient voltage signals, the high-frequency transient voltage signal caused by external faults through boundary will be attenuated and the signals caused by internal faults will be unchanged. In this paper, a new technique in which the combination of the S–transform and support vector machine (SVM) is used to analyze the transient signals, is proposed for distinguishing internal faults from the external faults based on the significantly difference of high-frequency transient voltage on the point of protection.

In this paper, the simulation of ±800kV UHVDC transmission line in which fault lightning stroke and non-fault lightning stroke, line short circuit occur shows: because there is fault current lumped parameter access to earth during the fault lightning stroke or ground fault, the voltage waveform decrease suddenly and cross repeatedly the zero line in 5ms time window；There is no fault current accessing to earth during non-fault lighting stroke, the disturbance caused by lightning is too less than value of the pole voltage. The voltage waveform comes from the protect position change up and down around the direct voltage line and decays to the pole voltage line in the 5ms time window at last. In the case of the fault lightning or ground fault non-lightning, the correlation degree of transient component and pole voltage line in the time window is little. On the contrary, it is large during the non-fault lighting. Above this, the correlation degree is calculated using 5ms samples. This kind of algorithm can resist random noise effectively,calculating speed is very fast. Many PSCAD simulations show that the algorithm can identify lighting disturbance correctly.

A novel transient component bus protection based on morphological bop-bottom-operator is presented in this paper, which takes the max top-bottom-operator of current traveling wave to fast distinguish the bus internal fault from external fault. The method is based on the principle that the high frequency component of transient traveling wave caused by external fault will be attenuated by the bus capacitance but the traveling wave caused by bus internal fault changes slightly. Simulation is carried out with PSCAD/EMTDC, the result verifies the bus protection is reliable and accurate. The novel bus protection also can treat lightning failure or lightning disturbance happened on transmission lines as bus external fault, without malfunction. Introduction

For both ends of the reactor with a parallel transmission lines, a method using Fault-phase voltage of low frequency component to Discrimine of the fault nature in Recovery voltage phase. In this method, different frequency bands is obtained by S-transform for Recovery phase of the faulted phase voltage capacity ,compare the low frequency part , in advance , determining the nature of the fault. Through theoretical analysis and a large number of verification of PSCAD, This method can effectively distinguish the fault type.

In this paper, a new method based on modal analysis and CPF method devoting to designing of generation adjusting plan which can alleviate stressful voltage condition considering energy saving is proposed. The voltage stability condition has relation with the generation and load distribution modes, usually only adjustment of load distribution modes has been noticed when there is a need to alleviate stressful voltage condition. Noticing that properly modification of the generation mode under stressful voltage stability condition can also reduce the power loss of power system and enlarge the voltage stability margin, a fast generation adjusting strategy designing algorithm is proposed. In the mean time, coal consumption of each generator is also considered. Participation elements is employed in this method to select the generators which are effective in adjusting process, continuous power flow calculation algorithm is used to trace the variation of power loss in power system. The simulation result on IEEE 39 system show that the method proposed by this paper can modify the voltage stability condition and enlarge stability margin to certain extent.