Research And Development On Plant-power Fast Transfer Device

In power plant, the reliability of auxiliary power supply is the principle requirement for generator set, power plant, and power system's safe operation. To ensure the normal operation of the power plant, it is very often for the power plant fast switching device to quickly switch to the alternative power, in case of losing power of the main busbar. The power plant fast switching device provides effective technical guarantee for the safety and reliability of the power system. How to judge switching conditions accurately in order to accomplish the switching operation at the optimal moment, as well as the high reliability and versatility characteristics of the power plant switching device, are of great significance to guarantee power plant switch timely.This thesis paper has studied the power plant fast transfer device in the following ways:First of all, the paper summarizes and analyzes the current status of the power plant switching device. Based on the summarization for the existing research results concerning induction motor restoration, this paper conducts an in-depth research for the electromagnetic transient process of the induction motor at the moment of power switching, as well as pointing out and discussing the shortages of the fast switching device hardware.Secondly, the paper conducts a comprehensive research on induction motor operation features at switching transient, as well as on the variation of the residual voltage by using PSCAD / EMTDC simulation software. Meanwhile, simulation test of the induction motor transient process is conducted under power plant fast switching, in-phase switching and residual voltage switching situation. Moreover, this paper optimizes and improves the extensive application of the switching criteria.Thirdly, based on the research of the mechanical and static voltage characteristics of the induction motor, this paper conducts a simulation test regarding the power plant switching process under high power supply or low side voltage. This paper proposes the concept of alternative power critical transfer time on the basis of eliminating plant fault.Fourthly, in order to obtain interoperability and scalability of the fast switching devices, this paper proposes MiniISA bus hardware structural platform which is based on MCF5282 microprocessor and centered on field-programmable gate array (FPGA). This design employs ideas of standardized function modules, realizes the application of the system main modules, analog input module and digital input output modules, etc. Each module's MiniISA bus function is achieved through FPGA. In light of adaptation of standardized intelligent bus interface, realization of common visiting model and data exchange among variant modules, improvement of the generality and expansibility, the devices can automatically meet the fast switching requirement among different buses.And, based on the research of embedded real time operation system ofμC/OS-Ⅱ, this paper designs the software system of the device. The software employs the idea of stratified functional blocks, obtains fast switching functions, low-voltage load functions, etc., by using a modular approach. The anti-interference measures of the hard ware and software are introduced to improve the velocity and reliability of the device.Finally, Using the model machine developed on this research program, a simulation test was peocessed, test results show this design principle of the system program and the switching is correctness and feasibility.