Research On The Electromagnetic Transient Simulation Modeling Of Internal Faults And Physical Experiment Model Of EHV/UHV Magnetically Controlled Shunt Reactor

In recent years,China's UHV long-distance transmission system has developed rapidly.The charging power of UHV lines is large,and the power load changes dramatically in China,resulting in increasing reactive power consumption in the grid.The contradiction between reactive power compensation and limiting overvoltage under different loads is becoming increasingly serious.The magnetically controlled shunt reactor(MCSR),as an important reactive power compensation equipment in the current ultra-high voltage(UHV)power grid,it has the ability to smoothly adjust the capacity,eliminate the operating overvoltage and limit the secondary current.Further study of its working principle and fault characteristics will be beneficial to the safety and stability of the power grid.In this paper,we take MCSR as the research core,and focus on five core issues,including its working principle,finite element modeling process,steady-state operation simulation,internal fault electromagnetic transient simulation and related physical experiments.First of all,we introduce the basic structure and working principle of MCSR,and analyze its working characteristics.Then build its model.In previous studies,the magnetic circuit decomposition method was used to construct the equivalent model of MCSR.This method has obvious shortcomings,transformers are used to replace the MCSR equivalently,It has low accuracy and can not accurately reflect the internal faults of the MCSR.Secondly,we use the finite element software Ansoft Maxwell to model the two-dimensional and three-dimensional model of the MCSR.The external circuit is used as the excitation source of the model,and the model parameters are based on the actual parameters.The simulation results show that the model can correctly reflect the working characteristics of MCSR,including steady-state characteristics,capacity regulation,internal faults and so on.In the study of internal faults,we propose a winding splitting method,and simulate the control winding inter-turn/turn-to-ground faults,network-side winding inter-turn/turn-to-ground faults,compensation winding inter-turn/turn-to-ground faults,control winding inter-phase faults.The simulation results show that the AC component of the master control current of the MCSR increases sharply,and the fault phase current increases sharply when the faults occur.These features can be used to design MCSR protection configuration.Thirdly,we use this model to compare different closing modes,and try to propose two new structures to improve the response speed of MCSR capacity regulation.Finally,we do some research on the physical experiment,and compare it with the simulation above to prove the practicability of the model.