Research And Design Of Control Unit Of Low-voltage Intelligent Circuit Breaker Based On MCU

The power-distribution network is user-oriented power network,which take a important role in power system.As the large-scale construction and transformation of power-distribution network in cities and countries,traditional electromagnetic low-voltage circuit breaker can not meet the request for automation of power-distribution network.So developping intelligent low-voltage circuit breaker have an extremely important significance.In some special occasions such as field with flammable or explosive gases,and high radiation,high voltage,toxic gases and dust,existing intelligent circuit breakers with wired communication cannot meet requests.High-grade intelligent circuit breakers produced by foreign manufacturers can offer wireless communication by use of Bluetooth. But the big investment in bluetooth hardware make this technology can not popularization.So in this paper,author proposed a supposition which bring infrared communication technology to the field of intelligent circuit breaker.People can establish point-to-point connection with devices by infrared communication technology without physical contact.In this paper,high-performance microcontroller AT89C51RC2 as core was used in control unit of intelligent circuit breaker with multiple function.The device can not only real-time collect parameters in field,but also have protection function including three-levels current protection,ground-fault-protection,over-voltage protection,under-voltage protection and ZSI protection.Large-screen LCD,LED and keys are used to compose excellent man-machine interface which lead more convenient and simple operation.In addition,two different communication unit are Established in control unit of low-voltage intelligent circuit breaker.One is a traditional communication module adopted RS-485 interface and Modbus protocol,the other is infrared communication module by means of infrared ray.Based on adequate learning and analysis of performance of components,measurement algorithm,implementation of protection and communication theory,the control unit of intelligent circuit breaker's hardware and software are designed,and anti-interface measurements are used in order to increase precision and reliability.Proteus is a powerful design and simulation software for embedded system,and sole EDA tool of real-time simulation,debugging and testing for MCU produced by different manufacturers.In this paper,the experiment hardware of system for protection function are designed in Proteus ISIS compile environment,and simulation and aberration analysis can be obtained in Proteus environment.By the result of experiment,The function and precision can meet requirements of design.