Study On Breaking Arc Charcterisyics Of DC Miniature Circuit Breaker

As a protective device,DC miniature circuit breaker is widely used in DC power,rail transportation,power train and ship in the DC system.The safety of its operation and the reliability of its action play very important role to the stable operation of the DC system.Due to there is no natural zero point of the DC interruption,which makes the DC circuit breaker breaking arc not as easy as AC arc extinguishing,so studying the breaking arc characteristic of DC miniature circuit breaker has a very vital significance.First of all,the breaking arc voltage and current data acquisition system of the DC miniature circuit breaker is set up,and the data is analyzed from the Angle of micro plasma.then the overall scheme design,hardware design and software design of the test system are introduced.In the hardware design,the load and the control circuit are designed in the form of multiple load in parallel,with solid state relay switched on or not,the connecting load branch is controlled.The acquisition circuit is composed of the current and voltage sensor and the data acquisition card,which can achieve high speed data acquisition.In software design,data collection and storage program realize the data real-time processing and acquisition through the producer/consumer structure mode.Filtering programs eliminate the noises in the collected signals by using digital filter.And the voltage and current power waveforms of the collected DC miniature circuit breakers are analyzed.Secondly,the distribution of voltage and electric field intensity along the arc length of the DC miniature circuit breaker breaking arc are analyzed.The physical characteristics of the arc-burning process of the DC miniature circuit breaker are analyzed,and the particle composition of the air arc plasma is simulated with the arc temperature,And the dynamic changes of the enthalpy and the specific heat of constant pressure with the arc temperature are further calculated by the particle composition.The physical characteristics of the dynamic change of the arc process and the voltage and current power waveforms obtained by the experiment are analyzed.Then,the arc burning process of the DC miniature circuit breaker is divided into two parts,including metal phase arc combustion and gas phase arc combustion,and analyzed.Finally,the topological structure of DC miniature circuit breaker arc suppression scheme is put forward,and the working principle and action process are analyzed.Power electronics branch of topology structure,the drive control circuit and buffer endergonic branch are studied.And the test circuit for the suppression scheme is set up.Testing for voltage current data of DC circuit breaker branch.IGBT valve group branch and buffer endergonic branch,the circuit breaker to the IGBT valve current transfer characteristic and IGBT valve group into the buffer endergonic branch current transfer characteristic are analyzed in different line inductance and different current level.