Research And Design On Controller Of Circuit Breaker For Smart Supply And Distribution Network

The low-voltage circuit breaker, as an important part of the electrical equipment of supply and distribution network, plays a crucial role in the circuit protection and control. In recent years, driven by the worldwide wave of smart grid, supply and distribution network has been developing towards the intelligent direction. However, as the current low-voltage circuit breakers are single-functional and incompatible with each other, they are unable to make the needs of the development of the intelligent supply and distribution network meet. Therefore, with the acceleration of the process of the intelligent network, the research of intelligent controller of low-voltage circuit breaker which is intelligent distribution network oriented has been of great importance in engineering application for the entire power industry as well as low-voltage apparatus manufacturer.To begin with, the functions and features as well as the development trend of the circuit breaker controller oriented to the smart grid have been analyzed on the basis of the introduction of the research background and situation of the issue. Then the protection and measurement algorithm, improved three-section current protection principles and controller-oriented Ethernet communication protocol have been discussed elaborately. At the same time, the overall design scheme of the controller which is multi-functional and equipped with the improved three-section current protection has been put forward in this thesis. The hardware and software design of the controller has adopted modular ideas. The design principles and implementation methods of the hardware and software modules have been elaborated. Several specific and feasible ways of the key technologies such as circuit breaker control, dual-power automatic conversion control and Ethernet communication of the circuit breaker have also been proposed in the thesis. In the end, several tests have been carried out to guarantee required functions.It is proved by research and experimental result that the controller of circuit breaker designed for the smart grid has the functions of circuit breaker control, dual-power automatic conversion control and Ethernet communication. In addition, an improved application of three-section circuit protection has been added. As a result, the requirements of the intelligent network have been realised and the design objective has been achieved with such a smart controller in a low-voltage circuit breaker.