The Research And Design Of Practical Algorithm Of Digital Protection For The Large Generator-Transformer Unit

With the development of power industry, the large generator-transformer units above 600MW are becoming the main units, whose operation would influence stability, reliability and economy of power system. The thesis presents some research under such a background, mainly including following contents:In the first two chapters, first to summarize current status of generator-transformer unit protection, and introduce some new technology used in digital protection such as the fault component protection principle and the adaptive protection principle.In the third chapter, mainly study the practical algorithm for generator-transformer unit digital protection, which is based on uncoupling of functional module. The completed algorithms include harmonic filter, sequence filter, frequency measure in real time, and some math calculation,which is free from influence of frequency fluctuation and decaying DC component. Besides that, there is some calculating methods of power and impedance. All that algorithms are adaptive to different sampling frequency, such as 12, 24 or 36 sampled data a circle. In the fourth chapter, according to the layer technique with modularized structure of software engineering idea, this thesis disassembles the protection system configuration to functional parts. It picks up common factors as modularized units, chooses appropriate disassemble points, and thinks about redundancy, then completes all aspects of module's standardization. The disassembled system would be demonstrated by functional module frames. The final part summarizes the research result and the imperfect work.