The Hardware Design And Reliability Study Of Intelligent Low-voltage Molded Case Circuit Breaker System

Low voltage circuit breaker is a switch device for connecting or disconnecting the powersupply network, and is widely used in low-voltage power system. Circuit breaker is the keydevice in power supply network, provides convenience and safety for people’s daily life andindustrial production. With the development of smart grid, the traditional circuit breaker isbeing phased out, the intelligent circuit breaker of the utility model is the continuousdevelopment and promotion. Compared with the traditional circuit breaker, intelligent circuitbreaker has the advantages of high control precision, easy adjustment and high reliability. Notonly has the basic protection functions, can also realize data acquisition, datastorage, parameter setting, human-computer interaction, remote communication and so on. Itprovides the guarantee for the realization of the distribution network of intelligence andinformation.This paper studies the hardware design of intelligent molded case circuit breakercontroller. The controller based on32bit microprocessor STM32F107VCT6as the mainchip, including: self generated power module, signal acquisition and control circuit module,communication module, human-computer interaction module and residual current protectionmodule.The paper introduces the principle of PCB design and the basic theory ofelectromagnetic compatibility. In order to improve the reliability of PCB, it analyzes factorsthat cause electromagnetic compatibility, the PCB layout, grounding design and power design.Hyperlynx is a simulation software to analyze the factors affecting the electromagneticcompatibility of PCB. This paper analyzes the influencing factors of the signal integrity of theclock network, and the clock network optimization design. In addition, The crosstalk betweenthe signal lines are simulated, it is applied to the PCB design of the intelligent circuit breakercontroller.Finally, set up the hardware test platform, the principle of test platform is: acquiringthree-phase current from the distribution network with hollow core transformer, this current isnot only the source of current signal acquisition, also to supply power for the controller work.Through the comparison of signal sampling value and set value to judge the power state andsend the corresponding instruction. The tests of platform include: self generatedpower test, signal acquisition and control test, all kinds of protection test, liquid crystal display and parameter setting test and Ethernet communication test. In addition, currentcalibration and Ethernet communication were tested at Zhejiang Technology Service Platformof Wenzhou Low-voltage Apparatus. Through the experiment and testing of the authority,verified the accuracy and reliability of the controller.