Optimization Of Arc Simulation Model For Miniature DC Circuit Breaker

In the operation of the low-voltage DC power grid system,the low-voltage DC circuit breaker is an essential protection component.Its main function is to quickly disconnect the fault current and ensure the smooth operation of all equipment in the line to avoid short-circuit faults,overvoltage or overcurrent damage.However,there are still problems that cannot be ignored in the development of the DC circuit breaker.First,in the DC circuit,the current is a constant rated value greater than zero and must be artificially reduced to zero.How to operate more quickly and safely is a research focus at this stage.Secondly,there are a large number of inductance and reactance elements in the DC power network.Because of this kind of power storage performance,if the power storage elements discharge after the fault circuit is removed,not only the power-off time will be prolonged but also the personal safety will be seriously endangered.The main work of this paper is based on the sub-project " Research on Arc Critical Current of Micro DC Circuit Breaker" under the research project " Research on Factors Affecting the Electrical Life of Micro DC Circuit Breaker",to model a prototype of micro DC Circuit Breaker(rated current 63A),and to design four schemes,namely,permanent magnet magnetism,arc striking plate material,permanent magnet position and some components(increasing magnetic sheet and corner iron sheet),and to calculate the electric power of arc by Ansoft electromagnetic simulation software and explore the influence of each scheme on the electric power of arc.The innovation of this paper is mainly to establish a simplified arc trajectory model,analyze and study the calculated arc electro-dynamic data,and finally do an on-off test to verify the circuit breaker’s electrical life.The experimental results show that the scheme of placing the permanent magnet at the corner iron plate has a good effect,and the average on-off time is 7.498 ms,which is almost the same as the average on-off time when the strong magnetic permanent magnet is used in the original model.The purpose of this paper is to provide ideas for the current research on how to quickly turn on and off DC circuits.In order to quickly and safely disconnect the miniature DC circuit breaker,the current common method is to add permanent magnets inside the miniature DC circuit breaker.Based on this,this paper expands the research method,that is,to study the influence of the placement of permanent magnets on the arc,and to consider the arc-related components inside the circuit breaker(magnet-adding sheets and corner iron sheets).By using Ansoft electromagnetic simulation software to calculate the electric arc power in the design scheme,and comparing and analyzing the results,the conclusion that the strong permanent magnet in the original scheme is changed into the weak permanent magnet with low price not only ensures the product quality,shortens the on-off time of the circuit breaker,but also reduces the production cost of the miniature DC circuit breaker and improves the economic benefit.