Advanced Materials Research Vols. 383-390

Abstract: Based on the early research of the efficiency evaluation index system of fire command automation system,combining the characteristics of fire command automation system of our country, elected AHP to identify multi-criteria comprehensive weighs of the third-grade indexes, and then constructed dual-binding evaluation model of grade and number.

Abstract: It is well-known that, the identification of the single-phase to ground faulted line in neutral non-grounded distribution systems is a difficult problem, due to its very small faulted current. This paper proposes a new method for the solution of this problem. The principle of the proposed method is to convert the neutral non-grounded system into a neutral grounded system temporarily by using a triggered vacuum switch based controllable short-circuit equipment. By time-domain numerical simulation, the proposed method is evaluated, and the simulation results have shown the effectiveness of the proposed method.

Abstract: The parameters of large wind turbine need to be adjusted timely to avoid excessive wind energy that will cause damage on the wind turbine itself. Based on the simplified mathematical model of wind turbine, we got the relationship curve between its parameters. When the speed of wind was higher than the rated wind speed, we figure out the value of pitch angle during the changes of effective wind speed to keep rated output power. Neural Network used to train the data and pitch control system was built, it used to adjust pitch angle once the wind changes, and maintain the output power at rated value. The complex mathematical relation can be replaced by the trained network model. Detailed simulation results have confirmed the feasibility and performance of the optimal control strategy, which protect the wind turbine from damage and prolong its service life.

Abstract: Due to the limited life of series-connected battery stack suffered from the imbalanced charging-discharging operation, the equalization management module has become the key part of a battery management system. To minimize the adverse effects caused by the performance inconsistency between individual battery cells, a battery equalization management module based on the super-capacitors was designed in this study. This module separated the imbalance status into three types, applied different control strategy according to the status, and balanced every sub-group respectively. Simulation and experimental results showed that not only the module made the battery pack charge and discharge balanced, but also the efficiency of equalization was improved.

Abstract: With people attaching importance to sustainable development and reducing environmental pollution, distributed generation technology is attracting more and more and more attention due to its unique environmental protection and economy. However, distributed generation will change with natural conditions so that it can not output power constantly and steadily, and most DGs are connected to the power system at distribution network side, this will cause system stability problem. In order to fully play the role of distributed power and avoid the adverse effects of its existence, a power conversion sand energy storage system to effectively regulate the system stability of distributed generation connected to the grid is presented. MATLAB/Simulink is used as a simulation and study tool in this paper, a system model of distributed generation connected to the grid is built and combined with actual operation in different environments to conduct real-time simulation analysis, the simulation results show that the power conversion system can enhance system stability of distributed generation connected to the grid.

Abstract: To meet the practical demands of some firms making CNC machine tools, a remote warning and diagnosis system is designed and introduced in this paper. The on-site information collection and communication module which is used to monitor the equipments can predict the failure before it occurs and send the data to the information center. It helps to reduce the failure and efficiently prevents serious accidents from happening. The advantage of the system is that it improves the remote service and repair, which makes it important for the designing of the remote monitoring system for large-scale mechanical and electrical integration products such as central air conditioning and elevator.

Abstract: An new approach to multi-task programming using Finite State Machine (FSM) integrated with the multi-task concurrence schedule mechanism of embedded real time operating system was proposed in this paper. Detailed procedures of the approach and two years’ application in an urban heating network were also presented. The approach exhibits a promising prospect in those industrial control systems where more than one highly demanding real-time task are controled concurrently. Both the calls between tasks and the internal state transitions are implemented in the form of concurrent, so that the efficiency of CPU is increased with reasonable arrangement and configuration of CPU.

Abstract: This article has completed the 3D solid modeling of the globoidal indexing cam by Solidworks, imported the 3D model to Mastercam, every processing surface of parts is analyzed, Choosed cutting tools and various cutting parameters for NC machining simulation, designed a set of spatial arc cam numerical control program conforming to the requirements of processing ,so as to enhance the accuracy and efficiency of 3D modeling and NC machining of the globoidal indexing cam.

Abstract: This paper presents a model designing and simulation realization of arc protection system based on GOOSE (Generic Object Oriented Substation Event) .It is proposed to fully use the logical node GGIO (Generic Input and Output) of IEC61850 in the modeling of intelligent electronic devices. The real-time data (data of arc intensity and loop circuit) are transferred by GOOSE message with time delay less than 4 ms. GOOSE message communications mechanism is introduced. Winpcap development packet is selected and the simulation program is written to transmit and capture the GOOSE messages.

Abstract: This paper analyzes operation problems of medium voltage switchgear cabinet in the electric power system. According to the international standards of IEC 61850, model the new arc protection device on the bus and analysize the relationship of abstract communication serivce inferface (ACSI) mapping to manufacturing message specification (MMS). Finally, MMS PDU formation and decoding are described specifically based on ASN.1 encoding rules.