The Development Of Current Protection Controller In 10kV Lines

Along with the development of national economy, more requests have been raised in the dealing-with the quality of power supply. As the terminating equipment in the power system, the reliability and the intelligent level of the circuit breaker affect the stability and the quality of power supply of the power system.This paper adopts the microcomputer mode for controlling breaker to protect fault and abnormal status of 10 kV distribution network. This thesis analyzes the characteristic of the instant inrush current which usually makes breakers operate unintentionally and single-phase earth fault. The reason which lines-selection methods at present usually go wrong is analyzed, and the method which uses time and secondary harmonic proportion to identify inrush current and use zero-sequence to identify the lines which single-phase grounds and to find the fault point is extracted. Finally, this paper gives the practical criterion of line selection and fault point allocation.The design makes microcontroller PIC18F458 of Microchip Corporation as central processor. The hard platform mainly includes peripheral interface circuit, power circuit, analog signals sampling circuit, ADC peripheral interface circuit, I/O and separation circuit, and communication module. According to the characteristic of working environment at field, it specially designs the power circuit, and designs opening controlling circuit for spring operation organization and permanent-magnet operation organization. Considering electromagnetic environment of the controller, the anti-EMI measures are adopted in hardware component. In software, it compiles the programs including identifying inrush current, the algorithm of line selection and fault point allocation, communication. At the same time, it gives the program flow process charts.At last, the paper designs the experiment scheme to validate the main function of the spring operation organization driving, fault line selection, GSM communication, and EMC, then analyses and compares the result. The paper is completed in hardware circuit, emulation, the correlative program and arithmetic and debug. The controller realizes the main function in design. The research and experiment result proves that: the design structure of controller is reasonable and modularized to satisfy the technology request. It is good of reliability and practical characteristic.