Research On Characteristics Of Voltage Self-balanced Interrupter For Multi-break Vacuum Circuit Breaker

Circuit breaker is an important equipment for safe operation of power system.Because of the saturation effect of vacuum gap,it is very difficult to improve the voltage level of vacuum circuit breaker simply by increasing the vacuum gap distance,and vacuum circuit breakers are mostly used in low voltage field.Therefore,scholars have turned their attention to the study of multi-break vacuum circuit breakers.By connecting several vacuum short clearances in series,the higher interrupting ability can be obtained.However,due to the influence of stray capacitance,there exists a phenomenon of uneven voltage distribution among each breaks of multi-break vacuum circuit breaker.In order to weaken the influence of stray capacitance and make the voltage distribution of multi-break vacuum circuit breaker more uniform,grading capacitor is often used to improve the voltage distribution in engineering practice.In this paper,the design of voltage self-balanced interrupter for multi-break vacuum circuit breaker is presented.By changing the material of interrupter shell into ceramic dielectric material for capacitors,the equivalent self-capacitance of the interrupter is increased,which makes the voltage distribution of the circuit breaker more uniform and get higher economy.Based on the static voltage distribution and dynamic voltage distribution mechanism of double-break vacuum circuit breaker,the reasons for uneven voltage distribution are analyzed.On this basis,the ideas of integrated and removable voltage self-balanced arc interrupters are put forward.The models of the two ideas are built by Solidworks,and the electrostatic field of the double-break vacuum circuit breaker under the two models is simulated by Ansoft,which verifies the feasibility of the design idea in theory.Then,the structure and characteristics of BaTiO₃-based and SrTiO₃-based ceramic dielectrics for capacitors are briefly analyzed.Four kinds of ceramic capacitor samples were prepared from two kinds of BaTiO₃-based and two kinds of SrTiO₃-based powders commonly used in industry through the process of forming,dispensing,firing and surface metallization in the laboratory.By measuring the capacitance and dielectric loss factor of four samples at different temperatures and frequencies,the dielectric temperature and dielectric frequency characteristics of various samples are obtained.At the same time,the voltage withstanding strength of the samples were measured by high voltage AC breakdown field strength test.According to the results of dielectric property test,the most suitable material for the design of this subject was selected,and the annular ceramic sample of corresponding size was manufactured.By measuring the dielectric temperature characteristics,dielectric frequency characteristics and high voltage dielectric loss of the annular ceramic sample,the electrical performance parameters of the sample were obtained,and its advantages and disadvantages were analyzed.Finally,the static voltage tests verify that the annular ceramic sample can improve the voltage distribution uniformity of the double-break vacuum circuit breaker,which lays a foundation for further research on the integrated voltage self-balanced interrupter.