Research On A Current Differential Protection For Power Hv/ehv Transmission Line

Due to the advantage of high sensitivity, simpleness, trustiness, and speediness, the current differential protection will be used as the main protection of high-voltage & exceed high-voltage power transmission lines more and more, with communication system of electric power fast developing. And on digital phase segregated current differential protection becomes the researching emphasis by domestic and alien protection's research organizations and manufactory companies. Aiming at this direction, the research of this paper is to design typed CSL1 03 digital phase segregated current differential protection for high- voltage & exceed high-voltage power transmission lines, using the newest digital protection technology and digital communication technology. The mainly contents of this paper are: 1. The significance of the topic of this paper is summarized, It is not only based on the principle of current differential protection but also combined the real problem of protection of our country and the developing reality & trend of electric communication in China. 2. The main design idea & schemes of communication interface of digital phase segregated current differential protection for high- voltage & exceed high-voltage power transmission lines is introduced in this paper. Based on analyzing the existed synchronization of current sampling and to forecast the develop trend of electric power communication system, the new synchronization of current sampling is presented. After studying the characteristics of communication error and the necessary of correcting communication error of current differential protection for high-voltage & exceed high-voltage power transmission lines, the idea of correcting communication error while running is proposed. And the method of correcting communication error with hamming code for this protection is produced. With meeting real serving, the channel supervising communication quality is designed. The schemes of synchronization clock of communication have been studied in this paper. 3. The fundamentals of the hardware design of digital current differential protection are presented. And the main schemes of communication of the current differential protection are produced in this paper. After several schemes are analyzed, tested and compared with, the hardware design of the current differential protection has been finished. 4. The several exited current differential protection criterions have been introduced. The study of this paper is mainly designing the software of typed CSL1O3 digital phase segregated current differential protection. And aiming at the serve of the protection, the research work has been paid attention to realization of the criterion of typed CSL1O3 digital phase segregated current differential protection. 5. After some simulating experiments, the results indicate that typed CSL1O3 digital phase segregated current differential protection can correctly serve with any kind of power system fault. It can meet the request of main protection of high-voltage & exceed high-voltage power transmission lines. The sample protection has been to served successfully on a 220kv transmission line. It can be expected that the typed CSL1O3 digital phase segregated current differential protection will be a new best main protection for high-voltage & exceed high-voltage p...