Pressure Line Points To The Study Of The Phase Current Differential Protection

With the rapid development of the power system, the power grid changes day to day. Digital phase segregated current differential protection based on fiber-optical must be used as the main protection of high-voltage & exceed high-voltage power transmission lines more and more, The systematic researches about the principles and techniques on the advanced protection system for UHV line are discussed in this dissertation, using the newest digital protection technology and digital communication technology.In this dissertation, the schemes of the current differential protection are investigated. The setting schemes of the resistance coefficient and the least trip differential current for the current differential protection based on sampled values using fault component are discussed. In this dissertation, because of the character of fault component, a scheme which has the optimum functions is provided based on several different criteria and adaptive principle, the simulation results based on ATP show that the scheme is a proper scheme for current longitudinal differential protection of UHV transmission line.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. In this dissertation, some related problems on the protection configuration, hardware and software designs of the advanced protection system for UHV line are discussed.