Applied Mechanics and Materials Vols. 738-739

Abstract: There are various kinds of damage caused by large amount of harmonic in power grid. The research object of this paper is the harmonic in power grid. A simple and practical harmonic detection program is studied. And the harmonic analysis module is completed. First the principle of harmonic generation is analyzed. And then, the signals of the voltage and current in power grid are collecting. At last, the hardware and software of the module are designed. The signals are analyzed and calculated by the module. The harmonic content is put out. The test proved that the module has the advantages of high precision, good reliability and low cost. It can be used on a variety of equipment.

Abstract: Although the doubly-fed generator group has a flexible ability of reactive power regulation, when a fault occurs in the power system, the ability will be closed to saturation and we need to adopt measures to support network voltage. In this paper, the model of doubly-fed wind turbine、SVC and STATCOM will be given. And the paper will provide a control system of the two dynamic reactive power compensation devices respectively. By power system simulation software Matlab and combining a regional power grid of Mengdon, both SVC and STATCOM are applied to the wind farm and the paper will analyze the characteristics of network voltage. The simulative results show that both the SVC and STATCOM can help wind farm voltage rapidly reconstructed after the fault. In addition, the STATCOM can better improve the transient stability of the wind farm and the compensation effect of STATCOM is better than SVC.

Abstract: In this paper, a new approach is proposed for optimal capacitor installation location using improved particle swarm optimization (PSO) algorithm. The improved PSO can solve the optimal discrete variables problem by forming global intelligent subgroups. The proposed method is implemented on the IEEE30 standard bus system. The obtained results are then compared with the empirical method to validate its effectiveness.Keyword: PSO; distribution system; Optimal power flow; Capacitor installation location

Abstract: With the development of information technology, computer and network have been widely applied into the area of energy consumption, energy conservation and pollution reduction. Information technology brings convenience into energy conservation and environment protection management, but at the same time, it also brings security issues. In the area of energy consumption, a lot of sensitive data related to national economy and society are on-line collected. Once data theft, it will bring immeasurable losses. Furthermore, data transmission between the existing energy consumption monitoring equipment and platform has no unified interface or standard. So this paper designed a chip, used as core chip in gateway, for compatibility, standards and safety during transmission, which will provide hardware and technical support for the government and enterprises to carry out monitoring of energy consumption and conservation, to achieve energy conservation and emissions reduction targets.

Abstract: The digital clock is a clock designed by digital circuit. Now, there are some limitations in the use and regulation of the digital clock in the large square. In this paper, the infrared remote-controlled digital clock based on FPGA can solve this problem well. This digital clock is composed of three parts: infrared remote control module, main circuit of the digital clock and function modules. And it is designed by the VHDL hardware description language, in the Quartus II software development environment.In addition, the digital clock has many extended functions, such as the hour timekeeping, alarm clock and temperature measuring. Besides, it has many advantages, including stable system , simple structure, short development cycle, fast speed and the strong usability.

Abstract: The magneto-rheological (MR) vibration reduction control technology is studied and a design and implementation of an automobile MR vibration reduction control system based on ARM9 is given in this paper. This paper introduces the system design process of embedded controller, current driver and other hardware, system software structure. Design of real time control system can realize the multi-channel vibration signal acquisition, control algorithm, CAN communications and other functions. The simulation and experiment show that, the control system software and hardware design can meet the functional requirements and have the advantages of fast response, high control precision and working stability.

Abstract: This paper describes a kind of LED dot matrix control technology based on STC89C51 MCU and complex programmable logic device CPLD, highlighting LED dot matrix display principle and the hardware and software implementation. This design has a flexible and programmable features, to ensure the stability of the system under the premise to achieve a variety of control programs on the LED dot matrix. According to this program,the breadboard adds external data memory, which can be used to extend the external bus, and this design has been successfully used MCU experiment.

Abstract: UHV AC transmission has a high transmission capacity, long distance, low loss, covers save etc. significant advantages, so it’s widely used in our country. But the placement of the UHV which was sent to select still major use projects empirical methods. This method lacks clarity and systematic. Meanwhile, it is difficult to adapt to complex changes in the overall demand for power grid. This paper developed a UHV AC placement selection method based on short-circuit current coordination. According to UHV grid and nearby 500kV grid short-circuit current coordination constraint, unreasonable impact point sent plan was excluded so that greatly unnecessary computational analysis was reduced. This can quickly determine the placement of reasonable UHV AC transmission project plan.

Abstract: In this article,an universal interface used in function modules of remote medical monitoring equipment is introduced.This interface was a versatile interface which can be used in the connections between all kinds of function modules and host of a remote medical monitoring equipment.Implementation of this universal interface not only improved the flexibility of monitoring equipment but also reduced the complexity of the design processes.This interface supported the hot-swap technology and hence provided easy-using,an uninterrupted monitoring during troubleshooting process and reduced maintenance time.This article introduced the design of this interface which was flexible and universal in three aspects,including its physical structure,circuit and software design.

Abstract: To realize the on-line quick analysis of the steady-state stability margin for the weak section of a power grid, a method of dividing the important generator groups according to the impact of the system equivalent impedance on the static stability limits of the section is presented. By using the dynamic information provided by the Wide Area Measurement System (WAMS), the center of inertia (COI) of the section of the two sides system is determined. Then the steady-state stability limits of the transmission section and the static stability margin can be calculated. The algorithm is verified by taking the out-play cross-section of West Inner Mongolia as an example, the results show that the static stability power limit and the steady-state stability margin of the section can be obtained accurately according to the presented algorithm. This algorithm can provide an effective analytical method for the online static stability security analysis of a power system.