Preparation And Properties Of Special Circuit Breaker For C-GIS

In the process of vigorously developing power transmission and transformation in China,the gas-filled high-voltage switchgear(C-GIS)has been widely used in engineering applications by virtue of its many performance advantages,such as being unaffected,meeting the application of all working conditions,and being smaller in size.The special circuit breaker for C-GIS is an important part of C-GIS.The design of special circuit breaker with large capacity,high performance and high reliability is the basis for the development of large-capacity C-GIS,It is of great significance to expand the scope of use of the inflatable tank.According to the upgrade demand of the large capacity of the C-GIS,the main technical parameters of the special circuit breaker for the C-GIS are determined as the rated current 3150 A,the rated short-circuit breaking current 40 kA,and the rated gas pressure 0.04 MPa.The insulation gap is estimated,the overall layout of the upper,middle and lower C-GIS is determined,and the type selection of the vacuum arc-extinguishing chamber is carried out according to this,including the type of the arc-extinguishing chamber,the layout structure,the transmission system,the insulation support structure The best scheme is selected from five kinds of options,such as operating mechanism,to determine the combination of horizontal vacuum circuit breaker driven by spring mechanism connecting rod,and to complete the overall scheme of special circuit breaker for C-GIS.Based on the research of the transmission system,the "four-link+rocker slider"transmission mechanism is designed.By solving the mechanical analytical equation,The optimization function is established with the minimum input force distance of the spring mechanism’s main shaft as the objective under a certain output force.The optimal design parameters of the mechanism under the constraint conditions are obtained by using the hybrid genetic algorithm through 30 times of solution,l1 is 74.5 mm,l2 is 64 mm,13 is 48 mm;Through the analysis of the influence of contact spring and opening/closing spring on the breaking performance of the circuit breaker,the "function principle" is used to calculate the appropriate contact spring and opening/closing spring for the spring operating mechanism,and the spring design program compiled by Excel is used to determine the final tension of the single-phase contact disc spring 5002 N,the final tension of the single-phase opening spring 1324 N,and the final tension of the closing spring 6300 N.Better match the mechanical characteristics of the circuit breaker of the and meet the opening and closing requirements.The electric field analysis software is used to calculate the field strength of the insulating support.It is found and analyzed that the field strength concentration is caused by the wedge air gap.By increasing the distance between the conductor and the contact surface,increasing the chamfer of the conductor,and other measures,the intensity value after optimization is significantly reduced,realizing that the overall field strength is less than 7.2 kV/mm,the maximum insulation edge is 3.11 kV/mm,and the surface field strength value of the insert is 1.21 kV/mm,and the insulation is effectively guaranteed.It conforms to the allowable field strength value.Finite element analysis software is used to calculate the strength of the insulated support under gravity,impact force,maximum electrodynamic force under short circuit,and the resultant force under three conditions.The maximum stress of the circuit breaker is calculated to be 8.12 MPa,18.94 MPa,54.03 MPa,and 68.45 MPa,which meets the reliability requirements.In order to better understand the mechanical characteristics of the operating mechanism and the matching characteristics of the vacuum interrupter,the mechanical characteristics of the operating mechanism and the transmission system are analyzed by establishing a three-dimensional model and importing the dynamic simulation software.The movement law is analyzed from the simulated opening and closing trend,which is consistent with the law of its moving contact movement changing with time.For better comparison,multi-parameter simulation test is designed to carry out comparative analysis.The collected data is used to fit the shape composition closing curve,which conforms to the movement law.Through the preparation of the special circuit breaker for the C-GIS,the mechanical performance test,mechanical operation test,mechanical life test and other mechanical performance tests are carried out,and the performance research is carried out based on the theoretical calculation,simulation and test results to meet the design requirements.The AC power frequency withstand voltage test,lightning impulse test and partial discharge test were carried out to test the electrical performance of the equipment.All tests passed the test,met the standard requirements,and passed the third-party type test,laying a good foundation for the mass production and operation of the equipment.