Study On Vibration And Noise Characteristics Of Anode Saturable Reactor

As an important component of the high voltage direct current transmission converter valve,the anode saturable reactor,which is connected in series with thyristors as an inductive element,ensures the normal turn-off of thyristors.Its frequent operation in and out of the magnetic saturation section and the complex structure of the reactor make the vibration and noise problem of the anode saturable reactor relatively prominent compared with other components of the converter valve.On-site accident reports point out that the long-term vibration of the anode saturable reactor is a safety hazard.Once a failure occurs,it may cause a short-term shutdown of the converter valve or even a fire in the valve hall.Therefore,studying the vibration calculation and analyzing the vibration characteristics of the anode saturable reactor has strong engineering significance.This thesis aims to address the issues of incomplete vibration calculation and unclear vibration characteristics of anode saturable reactors.Taking a domestically produced anode saturable reactor as the research object,the vibration mechanism of different sources of vibration in the reactor is analyzed.The electromagnetic vibration calculation and analysis of the reactor core and winding are realized by combining modeling and simulation with experimental analysis.Firstly,this thesis measures the magnetostriction characteristics of ultra-thin oriented silicon steel sheets.Using a strain-based magnetostriction measurement system,the silicon steel sheets are magnetized along the rolling direction to obtain the magnetostriction butterfly curves along the rolling and perpendicular directions under different magnetic flux densities.The hysteresis loops are processed into single-valued magnetostriction characteristic curves using mathematical methods for finite element software calculations.Secondly,this thesis establishes an electromagnetic-mechanical-acoustic coupling model for the single-core anode saturable reactor.A coordinate system that conforms to the core structure of the anode saturable reactor is established,and the magnetic permeability of the ultra-thin silicon steel sheet is converted into the magnetic anisotropy parameter of the homogenized core model through an equivalent formula.Based on the relevant theories of electromagnetics,elasticity,and acoustics,and combined with the measured magnetostriction curves,a magnetostriction vibration and noise calculation method applicable to the core of the anode saturable reactor is proposed.Next,to verify the feasibility and effectiveness of the proposed calculation method,this thesis conducts simulation and experimental research on the vibration and noise characteristics of a single iron core of an anode saturable reactor.Considering the magnetostrictive effect and Maxwell’s electromagnetic force,the proposed method is applied to complete the simulation calculation of the electromagnetic field and vibration noise of a single iron core,analyze the characteristics of electromagnetic vibration noise of a single iron core,design experiments to measure the vibration noise of a single iron core of an anode saturable reactor and compare and analyze the calculated results with the measured results to verify the rationality and accuracy of the numerical calculation model.Finally,this thesis extends the single-core electromagnetic-mechanical coupling model to the reactor and simulates and analyzes the vibration characteristics of the anode saturable reactor.A three-dimensional model of the anode saturable reactor is established,and the real current excitation of the commutation valve is used to analyze the working state of the reactor.The vibration values and effects cause by the magnetostrictive force,Maxwell electromagnetic force,and winding Lorentz force during the full cycle are calculated.In addition,to better approximate the reactor’s actual model,the casting material’s influence on the vibration of the reactor core and winding is calculated and analyzed.The research findings of this thesis can provide a calculation method for vibration prediction of anode saturable reactor products,laying the groundwork for subsequent vibration reduction optimization of anode saturable reactors.