Development Of General Software For Internal Fault Simulation And Protection Scheme Analysis Of The Huge Generator

With China's growing demand for energy, construction has begun on a number of large hydropower stations, and the single generator capacity is also growing. Due to the stable operation of the costly and large capacity hydraulic generators and the whole electric power system, it is particularly necessary to get effective configuration scheme of main protection for the generators.Due to the multi-branched structure of the huge generator's stator, different main protection scheme has different effect. Therefore, it is commonly based on the fault modality analysis of internal short-circuit that may occur within the generator, and simulated the generator internal faults to get the optimized design of main protection configuration scheme. To accelerate the research progress and to satisfy the demand of engineering analysis, it is currently imperative to develop general software for internal fault simulation and protection scheme analysis of the huge generator.Due to the complex structure of the stator winding, huge generator has many kinds of internal faults modality, and the total number of internal faults may be nearly 10,000. To get the fault sets by computer is a key problem of the optimized design of main protection configuration scheme. At present multi-branched wave winding structure or lap winding structure are adopted in high capacity hydraulic generators. This paper analyze the features of all fault modality that may occur within the generators with these two kinds of stator windings in detail and design a software that can generate respective fault sets and provide simulation objects fast. It can be greatly convenient for the optimized design of main protection configuration scheme. Meanwhile, it can help to understand every internal short circuit fault that may actually occur within the generator, and it has important reference value for running and maintenance of generator unit.Transient simulation of stator's internal faults in generator is the core and basis of the optimized design of main protection configuration scheme. This paper takes single coil stator loop as a basic unit, builds the transient simulation model of stator's internal faults in synchronous generator. Considering the characteristics and requirements of the engineering applications, the model also employs the simplified calculation method based on dual damper bars in each pole, which can improve computational efficiency roughly on the premise of satisfies the accuracy requirements for engineering calculation. The transient simulation model of internal faults, the simplified calculation method, and the design of the simulation software are presented in detail.As the stator's multi-branched structure, the generator has lots of connection types of neutral point. To get the optimum design of main protection configuration scheme, it must to take statistical analysis on maximum protection range for every connection type of neutral point. The computational process is complex, and the computation is very complicated. According to the research and application of the main protection for generator, this paper introduces the basic principles and implementation approach of the main protection for generator, and develops the protection configuration scheme analysis software. The design idea and flow of the software are presented in detail. The software can analyze the general performance of any main protection configuration scheme, with the help of the fault modality analysis software and the transient simulation software. It is a good research tool for the optimized design of main protection configuration scheme for generator.At present, the General Software for Internal Fault Simulation and Protection Scheme Analysis of the Huge Generator has been already successfully applied in a series of projects, such as the generators in Pubugou power station, Zhexi power station, the right bank of the Three Gorges power station, and so on. It establishes a good research platform for the internal fault simulation and protection scheme analysis of the huge generator.