Advanced Materials Research Vols. 354-355

Abstract: Reactive power optimization that is optimized by Simple Genetic Algorithms has many limitations. According to the problem of reactive power optimization of high voltage system, the Simple Genetic Algorithms is improved. The improved algorithm is applied in reactive power optimization of IEEE-6 bus system, the results indicate that the improvement is effective and it can accelerate the convergence speed and enhance the ability of optimization.

Abstract: An adaptive forecasting method of branch power of the urban power grid is presented. The implementation is accomplished by utilizing three basic load forecasting methods using Multi-model technology. After forecasting the load of one bus, two methods are used to get the branch power including distributing bus load and forecasting it directly with history data. The proposed branch power forecasting method is tested on one urban power grid. The simulations imply that the adaptive method is more efficient than that using single model.

Abstract: General evaluation methods applied in comprehensive evaluation of transmission and transformation project are slightly insufficient in terms of considering index coordination, and radar chart can solve this problem. For the shortcomings of traditional radar chart, AHP and entropy weight are combined to get comprehensive weight which is converted into angle to reflect the influence degree of indexes to evaluation objects; angle bisector is introduced as index axis and the eigenvector is extracted to get the unique evaluation result. On the basis of stage evaluation, an index system of comprehensive evaluation based on project implementation effect and management level is established. By applying improved radar chart, the comprehensive evaluation of three voltage levels actual projects shows the practicality of established index system, and validates the feasibility and effectiveness of improved radar chart.

Abstract: For the complexity of power supply system design and calculation process in mine, a visual approach is presented.The integrated program with power mapping, analysis alculation and document management platform, the advanced visual programming technology, activex automation technology, object-oriented design methods are used with the secondary development using its built-in vba on the autocad platform.The entire system is divide into drawing and design calculation and output module with modular theory, the database is used as core for combining into a unified and organic whole by associating primitive objects and data. Studies show that the method can quickly and accurately complete the power supply design, it is important for power supply safety in mine.

Abstract: In this paper, a grid-connected model of inverter interfaced distributed generator is built , which is used for researching the different effects on the traditional current protection comparing with the rotating interfaced distributed generator. Different protection schemes are introduced to deal with the different models, and the inverter interfaced model is built on DigSILENT/PowerFactory, Simulation results have verified the validity of the scheme proposed.

Abstract: A method was proposed to throw light on the initial period of cascading failure that would be the best time to implement prediction and prevention. A more accurate hidden failure model which considers fault locations and protection schemes was created, as well as a conductor temperature-outage probability model depicting tree-to-line contacts happened in the blackout frequently. It reveals the physical process of cascading failure more clearly and demonstrates that differently located fault which may trigger different PEFD of hidden failures and different ambient situations can both result in different outage sequence.

Abstract: The bus will experience different voltage sag when fault occurs at different location. Based on the non-liner profile characteristic of voltage sag measured at the bus, the paper proposes a new fault location method. Firstly, it obtains the analytical expression of each section based on the relationship between voltage sag and fault location. Then calculate the fault distance using chord secant method and identify the faulted section through the minimal deviation of fault distance. The combined two results of fault distance and faulted section make fault location accurately. It overcomes the difficulty of radial power distribution systems fault location. Through simulating for the IEEE 13 node test feeder with different faults, including various fault resistance, loading variation and the connected distributed generation, it proves the method’s accuracy and effectiveness.

Abstract: The Shuttle AS/RS System, which is one kind of crowded, highly effective, quick, safe warehouse memory system, has realized brand-new pattern of crowded memory for the warehouse. This warehouse system includes the steel structure tray shelf, the coordinate hay stacker and the shuttle trolley. The hay stacker transports the goods to the entrance and lays them on the shuttle, the shuttle trolley transports the pallet together with goods to region of shelf memory. This article mainly introduces the Shuttle AS/RS, which includes its structural style and the application characteristic.

Abstract: This paper presents an algorithm using a stepwise programming method to determine the suitable locations for capacitors installations and their ratings in distribution networks. The Voltage and loss reduction capability of nodes are regarded as input indices. The fuzzy inference method is used to obtain capacitor placement suitability of every node. The node having the highest suitability is selected as the compensation node. The energy losses of three time periods and the peak charge are modeled as optimization objective. Fuzzy multi-objective programming is used to determine the proper sizes of the capacitors. Considering the each capacitor rating interaction, the circulation calculation method is used to recalculate the capacitor rating for compensated nodes. The results of test system demonstrate the effectiveness and practicability of the method.

Abstract: The paper firstly introduces the situation of our substation grounding system. The author based on resource conservation to point out the necessity and urgency to promote the efficient material. Then, from the aspects of technology properties and technical performance, profound comparison is made between copper-clad steel and traditional conductors. Last but not least, in order to analyze objectively, the paper based on a real 500kV substation to discuss from the point of economic properties. All testify that copper-clad steel indeed a perfect grounding conductor.