Research On Electric Field Distribution And Insulation Performance Of Air-core Reactors

In recent years,the electric power industry of our country has made great progress.The demand for the reactor in the construction of the power system is also increasing.By virtue of their own advantages rise directly to a high position of reactor status in power system,become one of the indispensable equipment in power grid construction.But in the process of running over a long period of time,due to various causes of dry type air core reactor burned not only makes the events emerge in an endless stream,reliable and stable operation of the power system is facing a sev ere test,causing adverse effects to the normal operation of enterprises and the relevant departments,even causing distress to the broad masses of the people's daily life,make the country suffer great economic losses.The statistics of the related failur e data of the dry air core reactor which is actually put into use,we find that the two important reasons leading to its burning damage are insulation cracking and dendritic discharge.The uneven field strength distribution of dry air reactor is likely to cause partial discharge,further breakdown the insulation medium in local area,destroy the performance of reactor,and even cause accidents such as burning and damaging of core reactor.Air core reactor encapsulated winding in magnetic field will bear the electric power of the encapsulated displacement deformation will occur in the small electric power under the effect of displacement deformation in the process of continuous accumulation in the resulting equipment if things go on like this,the encapsulation insulation cracking air core reactor.In order to ensure a smooth and reliable operation of air core reactor,this paper adopts ANSYS Maxwell system of running voltage 35 k V,rated capacity of 20000 kvar air core shunt reactor is studied by finite element analysis,the stable operation and switching over voltage under two working conditions and electric power problems are carried out in-depth research,provide an important reference for the design and manufacture of air core reactor the reliable and stable operation.The main contents of this paper are as follows:(1)According to the statistics of the relevant failures in the accident cases of air core reactors,combined with the structure and production technology of air core reactors,the failure process and main causes of air core reactors are analyzed.(2)The calculation principle and field coupling finite element analysis method based on 3D electromagnetic field,and the establishment of a three-dimensional finite element model of the selected air core reactor design specifications consistent parameters using ANSYS Maxwell,mainly for the whole air core reactor,air core reactor encapsulated internal winding layer and the relationship between the inter relationship between the three finite element mode ling.(3)ANSYS Maxwell is used to simulate and analyze the electric field of the three dimensional model after steady operation,and the corresponding electric field distribution characteristics and field strength of air core reactor are obtained.Aiming at the frequent switching overvoltage envelope insulation air core reactor affected,switching results in a random sample of 10 groups of test data from the 50 groups were analyzed with 35 k V air core shunt reactor insulation level can withstand the operating overvoltage limit value,and draw the conclusion that frequent switching operation will accelerate shunt reactor insulation damage.(4)The operation of the air core reactor under various steady-state entrapments by axial and radial electric power is calculated.The calculation process,and explores the air core reactor transient current and input power,comparative analysis of the air core reactor stable operation of switching transient two conditions of electric power distribution vector,according to the simulation results and combined with the wound the process of air core reactor encapsulation,are running air core reactor more vulnerable to radial electric power influence and destruction.At the same time according to the mechanical properties of air core reactor insulating materials for electric power generation,steady operation and switching transient two conditions on the envelope insulation damage inquiry,accounting for encapsulation insulation can produce the minimum thickness of insulation el ectric power constraints on the two conditions.The research object of this paper is a air core shunt reactor with a running voltage of 35 k V and a rated capacity of 20000 kvar.The simulation conclusions and actual situations are compared and analyzed each other,which confirm each other.The conclusion of this study has certain reference value,and provides important decision basis for safe and smooth operation of dry type air core reactor and even the whole power grid.