Research On Intelligent Release Based On ARM System

Low voltage circuit breaker is a kind of control and protection apparatus in the low voltage network, which can be used to close and drop out normal current ,overload current as well as short circuit current. The release which is the central part of low voltage circuit breaker performs all kinds of protection and control functions and the intelligence of release can greatly advance the progress of circuit breaker. With the development of sensor technology, computer technology, micro-electronics technology, power electronics technology and network communication technology, the release evolves from thermal type, electromagnetic type, electronics type to network type intelligent release based on micro-controller.In this paper, intelligent release for low voltage circuit breaker is designed, which is based on the ARM core micro-controller, the embedded real time multi-task operating systemμCOS and the CAN field bus communication .The release designed carries out the functions of overload current protection, short circuit current protection, grounding protection, LCD parameter displaying, parameter setting, communicating control as well as low voltage network power quality monitoring.On the hardware design, micro-controller LPC2294 based on ARM core is adopted as the central controlling unit .The hardware system also includes parameter sampling unit, PLL frequency synchronizing unit, LCD parameter displaying unit, key parameter setting unit, action performing unit as well as CAN communicating interface unit.On the software design, embedded real time multi-task operating systemμCOS-IIis established to connect the lower hardware layer and the upper application software; current protection(overload current ,short circuit current, grounding current) mathematics model is given; FFT is applied to analyze the low voltage network power quality parameters. The whole software uses C language to program and is debugged based on ADS environment.LPC2294 with CAN controller implements the embedded network control, which enables the circuit breaker to communicate with the remote main PC computer. Using VB language to program the monitoring interface to display the line parameters such as current, voltage, power quality parameters as well as faults information, to set parameters remotely, to give out the control commands and to inquire the history data.For ensuring the Electromagnetic Compatibility (EMC) of the system, some practicable resisting interference measures on software and hardware have been adopted. The experiment result proves that the intelligent protection control and the embedded network communication both reach the product design requirements.