| The characteristics of the reverse distribution of resources and loads in China,the development of clean energy should increase the proportion of energy.But the high voltage direct current transmission system does not fall,may point to the point,the high power,the long-distance direct electric power to the load center,therefore becomes our country to develop the UHV project the first choice.Especially on the business areas covering 26 provinces(autonomous regions and municipalities),more than 88%of the land are,covering a population of over 1 billion 100 million people power national Power Grid Corp,is the development of UHV as building global energy Internet,crucial development direction of smart grid.As the development of UHV DC transmission technology in China is the purpose of long-distance,high-capacity transmission,regulation of electrical energy.Most across many provinces and cities,and to reduce the impact on the production and life of the masses,the UHV transmission line channel planning in a remote road,after the topography is complex and changeable,anti break pressure,line operation and maintenance difficulties.At the same time,because of the large capacity of compliance,once the failure or defects,resulting in economic losses and adverse effects.Therefore,it is urgent to select a convenient,reliable and easy to operate fault point distance measurement and mature calculation method.Using the method of one side of the transmission line to calculate the fault point distance is one of the most important research directions in the field of HVDC fault location.By using this method,the fault wave can be detected in time and effectively,and the distance measurement can be calculated by the traditional traveling wave fault location algorithm.However,under the condition of theory,the algorithm is difficult to be applied in practice in the face of complex environment and many interference waves.This paper is based on the above problems,creatively introduce mathematical morphological gradient transform function,complete interference filtering on the outside combined with the traditional distance measurement algorithm,and to calculate the wave of extreme elimination,thereby greatly reducing the ranging error,the operation method is more practical and accurate.Based on the above ideas,this paper focuses on the process of optimization and improvement:(1)Analyze the research object,the fault happen on the DC line conditions,types and process of extraction(assumption)analysis,to collect all kinds of waves for comparison,find out the key to the analysis of traveling wave,and deduces the key interference factors exist and the lack of body wave.(2)Carry out modeling analysis,the actual operation of the UHV DC line network and equipment research,summarize the key parts of the composition and characteristics of mathematical modeling to provide ideas and practical reference.After the completion of the above work,the application of the PSCAD power system simulation software to establish the HVDC transmission network model and the simulation data of the possible failure point.The normal operation state,the external force damage(broken line or ground discharge),and the lightning interference are analyzed.The experimental results show that the above viewpoints are in accordance with the actual demand.(3)The introduction of the new algorithm,to solve the problem of error faced by traditional calculation method the advantage of gradient transform in mathematical morphology,construct a can filter the interference wave,and can be modified(excluding)with extreme value analysis of traveling wave crests and troughs on,therefore proposed a multi-resolution morphological gradient the correlation function theory in UHV DC transmission line fault location on the application of the final research project.The calculation process is through structural elements into two types,separating out the desired calculation of the traveling wave,structure using traveling wave fault location method for HVDC transmission lines on the corresponding function,finally realize the use of unilateral complete measuring point fault of HVDC transmission line positioning and ranging.In this paper,two kinds of simulation software(PSCAD and MATLAB)are used to simulate the model.Through the final calculation,the calculation method can be a wide range of elimination of errors,distance judgment narrowed to within 0.2 km range.Therefore,this article relates to the new ranging method can be used to fault location in unilateral fault line,and can effectively identify the external disturbance,purification with measuring wave purity,and thus greatly enhance the fault distance measurement accuracy and practical operability. |
PDF Full Text Request