Research On Space Magnetic Field Distribution And Shielding Of Smoothing Reactor

With the rapid development of China's UHV DC transmission technology,UHV DC transmission lines have become increasingly prominent in the main grid of power system.Dry-type air-core smoothing reactor has been widely used as an important equipment in DC transmission project.However,it has become one of the main sources of electromagnetic pollution in converter stations,which not only poses a potential health threat to the staff and nearby residents,but also may interfere with the surrounding electrical equipment.The problem of magnetic field pollution caused by DC transmission engineering has received more and more attention.Therefore,the research on the spatial magnetic field distribution characteristics of dry-type air-core smoothing reactor is becoming increasingly urgent.Research on the spatial magnetic field distribution of air-core reactors was mostly focusing on the power frequency magnetic field generated under AC condition,while the smoothing reactor mainly operates under DC condition,where installation,arrangement and quantity of reactors is quite different.Thus,the distribution characteristics and nature of their spatial magnetic field are diverse,and the shielding methods are quite different.Therefore,it is of great practical significance to study the distribution characteristics and shielding measures of smoothing reactor spatial magnetic field.In this paper,simulation and experiment is used combined to study the smoothing reactor spatial magnetic field.Firstly,the spatial magnetic field distribution characteristics of smoothing reactor in a converter station were obtained through field test.After that,the influence of the geomagnetic field on the test result was analyzed,the magnetic field distribution at different levels and of the two pole bus smoothing reactor were compared.Secondly,the simulation model of smoothing reactor spatial magnetic field calculation was established,which was verified by comparing the simulation result with the field test result.Based on this,three types of spatial magnetic field shielding measures of smoothing reactor were studied:a)installing a shield plate under the smoothing reactor;b)installing a cylindrical shield on the periphery of smoothing reactor;c)installing a shield at the staff channel.The effects of material,size and structure of the shield were analyzed.The effect of the shield on inductance and electric field distribution of smoothing reactor was analyzed,and feasible project proposal of space magnetic field shielding was put forward with good shielding effect.Thirdly,the scaling rules of smoothing reactor was proposed in order to verify the shielding measures.The small-scale model and the experiment platform of smoothing reactor were established.The reliability of the scaling criterion was verified at first,by measuring the surrounding magnetic field of the scaled model and comparing it with the spatial magnetic field of the real model.Then the small-scale model was used to verify the shielding measures.The magnetic field before and after the installation of shield were measured and compared with the simulation result to verify the reasonability and reliability of simulation result.The research of this paper provides a reference for the magnetic field distribution of smoothing reactor in converter stations.The result has important engineering application value,providing practical guidance for the spatial magnetic field shielding of smoothing reactor.