Tao Dajun

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.

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 and analysis of stator temperature for high voltage generator prototype with rated load

High voltage generator is a new type of generator. In order to determine if the innovational structure of high voltage generator can satisfy the requirement of high voltage generator with rated load, the temperature of the high voltage generator is analyzed and calculated. The electromagnetic of high voltage generator is analyzed with FEM, and the 2D model of electromagnetic field is proposed to calculate the loss of high voltage generator. According to the basic laws of heat transfer and the differential equation of heat conduction and its boundary conditions, 3D physical model of temperature for high voltage generator is established. According to the theory of fluid similarity, heat release coefficient of every part in stator is derived; the temperature field distribution of stator is obtained. Then, the correctness of the analysis is proved by the experiment. The conclusion of this paper provides certain theoretical significance and practical value for the reliable design and operation of high voltage generator.

Calculation and analysis of saturated powerangle characteristic and reactances variation for new high voltage generator

A novel high voltage generator (HVG) with cable stator windings is studied in this paper. compared to conventional generator, stator teeth of the new HVG are longer, flux flowing through each layer of its armature windings changes larger, operation characteristics also vary to adapt to its innovational structure. Since powerangle characteristic plays a significant role in the research on generator static stability, it is very valuable to study it for the new HVG. Therefore, taking a new HVG prototype rated at 162.5kVA/5kV as research object, saturated power-angle characteristic at rate voltage and rate field current is studied with the field-circuit coupled method. Steady reactances at different power angle are also calculated using the mathematical model considering cross-magnetizing phenomenon. Results are analyzed systematically and some useful conclusions are given, which will do favor in the follow-up study of the new HVG.