Ge Baojun

Analysis of high-voltage generator stator windings sudden three-phase short-circuit and loss of excitation fault

Base on a prototype of the 130kw/5kv high voltage generator, the system simulation model is set up for the generator stator windings suddenly three-phase short-circuit failure and loss of excitation failures. The dynamic simulation compared with experiment on DJ18-1 synchronous generator, it reaches conclusion that the system simulation model is correct. The current of the high-voltage generator stator windings three-phase short-circuit is far less than of the conventional three-phase generator short-circuit by simulation analysis; and if the high-voltage generator can be come into stabilized asynchronous running condition after loss of excitation, that offers time to clear fault. This reduces expense caused by its step-out and stoppage, and further improves operation reliability of generators and the electric power system.

Systematically study on the static power-angle characteristics of a high voltage cable-wound generator prototype

High voltage cable-wound generator is a new kind of generator, which can be directly connected to the power grid. Basing on the fundamental theories of electrical machinery, the expressions of power-angle characteristics of high voltage cable-wound generator prototype with excitation regulator and without excitation regulator are deduced in this paper. Combining with the parameters of a high voltage cable-wound generator prototype and a typical conventional synchronous generator, the power-angle characteristics variation law of the high voltage cable-wound generator prototype and the conventional generator are obtained by simulation. It is found that the power-angle characteristics of the high voltage cable-wound generator prototype are better than that of the typical conventional generator.

Multivariable bilinear subspace recursive likelihood identification for pumped storage motor

To improve precision for model identification result of pumped storage motor, a kind of multivariable bilinear subspace recursive likelihood identification for pumped storage motor is put forward. Firstly, pumped storage motor magnetic filed equation is given, pumped storage motor model based on extension Kalman Filter is established, two-set identification models are constructed by coordination by utilizing two-group state vectors of resistance and inductance and two-set models work cooperatively to construct circulation identification algorithm; then, introduce subspace identification strategy, establish relevant data estimation equation by utilizing block Hankel matrix and realize valid identification to system parameter matrix by adopting least squares (LS); validity of proposed algorithm is verified by simulation experiment in matlab platform and hardware environment.

Teaching innovation of professional course of postgraduate in materials science

Professional course teaching is one of the effective ways of educating postgraduate. According to the characteristic and training objective requirement of professional course teaching about engineering master of modern materials science, this paper analyzes the shortage of current course teaching. Also, the paper discuss the reform and innovation of postgraduate course teaching in many ways of optimizing postgraduate professional course system, professional skeleton curriculum provision, postgraduate course teaching reform, practice teaching platform and base construction of professional skeleton course.

Study and Practice in Major Diversity of Undergraduates Program

With the change of higher education from the Elite to popular personnel training, the explore and practice in educational reform are done to realize the different levels of education and individualized training, to increase the students’ practical hands-on capacity and self-learning ability, to make and implement the major diversity personnel training program.

Notice of Retraction Slip Influence in the Course of Powerformer Loss of Excitation

Powerformer is a net new high-voltage generator that can be set directly to system. The simulation method of Powerformer loss of excitation based on MATLAB/simulink is proposed. Using the simulation method to study slip during Powerformer loss of field, and analyze slip impact on the electric value of Powerformer stator and rotor. From the rotor heating, it is not possible affect the safe operation of the rotor because the rotor body additional temperature, during the asynchronously operation of Powerformer loss of excitation. It proves the transition from out-of-step to the steady-state asynchronous operation after Powerformer loss of excitation is asynchronously operation. It provides a reliable basis for the Powerformer actual operation.

Calculation of static stability limit of high voltage generator with constant active power

In order to study the static stability limit of high voltage generator, a mathematical model at high voltage generator leading phase operation is proposed; the calculation results of high voltage generator of the electric quantity of reactive power, terminal voltage, terminal reactive, terminal power angle are obtained at the static stability limit by using the analysis with constant active power. The comparison between the static stability limit of high voltage generator and conventional generator is analyzed with example. The results show that the static stability limit of high voltage generator is better than that of conventional generator. Finally, the correctness of the simulation is proved by the experiment.

Notice of Retraction Modeling and Simulation of Short-Circuit Loss of Excitation in Powerformer

In order to analyze the performance of powerformer under loss of excitation (LOE) condition more effectively, in this paper, firstly, based on MATLAB/Simulink, the simulation model is constructed, the direct short-circuit LOE and the excitation winding forms short-circuit LOE with de-excitation resistance are simulated by the model; Secondly, the waveforms of excitation current, rotor speed, active power, reactive power, stator current are given; Thirdly, the results are analyzed detailed. In addition, the model can also simulate other LOE faults.