Adaptive Distance Protection Device

The main protections for high voltage transmission line are usually made up of pilot relaying and distance relaying. This paper ,based on the application of microcomputer digital processing and intellect and adaptive relaying principle, describes a study of an adaptive distance relaying in the course of developing the new type of protective relaying device for 110kV and higher voltage transmission line , which combines the horizontal collaboration task .In this paper, based on the analysis of conventional distance protective theories and the description of adaptive control theory , the basic concept and the construction of adaptive distance protection are explained. According to comparison, the adaptive distance protection has great superiority .In real power system , the system frequency usually fluctuates along with the load . The electric quantities surveying is error if assuming frequency constant .In this paper, the surveying method of adaptive frequency fluctuation is introduced, which can remove error.The design of wave filter in adaptive distance relaying is elaborated and simulated, which can greatly progress the functions of distance relaying.The basic structure of hardware and software system on this device has been introduced . And the tests show that the adaptive distance relaying is very reliable and has good function target.