Research On The Intelligence Releaser Of High-Voltage Circuit Breaker

High voltage circuit breaker is one of the most important electric apparatus in power supply system, which is provided with the function of breaking and making short circuit current in order to protect power system and equipments as well as re-close the circuit even under faults condition including short circuit.With the rapid development and wide application of computer technology, data process technology, control theory, sensor technology, communication technology, power electric technology in electric apparatus's field, the conception of electric apparatus intelligent is presented by researchers.At present, the main characteristic of intelligent circuit breakers can be included as follows: self-condition monitoring and faults diagnosis of circuit breakers, electric network faults diagnosis and remote information transmitting technology, intelligent control of automatic reclosing, and synchronism (phase selecting) technique and so on. The intelligent will be an important trend of the development of high voltage switchgear in future.Releaser is the hardcore of circuit breaker. Therefore, the intelligent of releaser can greatly promote the intelligent of circuit breaker.Since traditional releasers mostly are electromagnetic, it is hard to control their traits.In this paper, recur to microelectronics technology and digital signal processing technology, intelligent releaser is developed with digital signal processor (DSP chip) as center. The function of releaser can be included as follows: releasing function, online measure function, diagnosis function and phase-select automatic reclosing function.In this paper, the transient course of short circuit current is detailedly analyzed at first, and the derivative of current is adopted as short circuit criterion. After analyzing and comparing digital filtering arithmetic, the Improved Fourier Transformations (IFFT) is adopted to separate the fundamental component of short current. Furthermore, the corresponding arithmetic derivations and simulation results under MATLAB are given.Then, the conception of The Optimal Reclosing Time is introduced base on the researches on the automatic reclosing theory in the world. In this paper, the project of The Optimal Reclosing Time suitable for application is presented according to the transient analysis of circuit breakers' making process. Simulation results indicate that this measure adopted by automatic reclosing can greatly reduce the impact current and overvoltage.Thirdly, DSP chip TMS320VC5402 produced by TI Incorporated is adopted as control center. The functions of A/D sample, display, output, control and perform are realized with the design of daughter board by interfaces expanded based on DSP Starter Kit.Lastly, the software programming is given, and the emphasis is the realization of FFT on fixed-point DSP. Besides, the corresponding test results are provided.