Applied Mechanics and Materials Vols. 448-453

Abstract: The static voltage stability of power system with wind farm is simulated by fuzzy simulation. This method is able to calculate not only the expectations and standard deviations of diagonal elements of Jacobian reduction matrix with the uncertain parameters but also the static voltage stability indicator based on the credibility theory. The method is characterized in that the impact of the assumptions of distribution function type of uncertain parameters and parametric statistics is avoided by this method. The calculated results are impacted only according to the actual changed range and the types of membership functions of uncertain parameters. Finally the calculation results based on that method are compared with the calculation results based on two-point estimation method and Monte Carlo simulation method. The results show that the superiority and accuracy based on the method is proved.

Abstract: This paper proposes a new approach which applies Cantor-like search strategy to computing critical clearing time (CCT) after searching the initial search interval of fault clearing time (FCT) by advance-and-retreat predictor-corrector technology. On the basis of discussing the mathematical nature of computing CCT based on time-domain simulation, the work started with the comparison of conventional computer linear optimization search strategies, then combined Cantor-like search with transient stability analysis feature and realized CCT rapid calculation with the classical Dichotomy substituted. Simulations on New England 10-generator 39-bus system demonstrate that this new algorithm has a good advantage over efficiency and precision, as well as its engineering application prospect.

Abstract: This paper set up the real-time simulation model of FOCT by means of RTDS. The equivalent model of FOCTs digital closed-loop control system was created by simplifying that systems deviation and feedback .The temperature was also introduced in that model above according to the temperature change law of the optical fiber Verdet constant and λ/4 wave plate phase delay and the mathematical model about λ/4 wave plate parameters of the light intensity received by the detector. The results show that the real-time simulation model of FOCT is reasonable, and can simulate FOCTs steady state temperature characteristic. Its transient characteristic is not bad and it can be used for testing smart substations correlative equipment.

Abstract: Switching control of micro-grid operation modes belongs to short time scale control level, this paper proposes three-tier structure of micro-grid energy management system suitable for switching control of micro-grid operation modes on the basis of the analysis of micro-grid operation mode switching requirements for the control system, and builds micro-grid central control system based on multi-agent technology aiming at the coordinated control of micro-grid operation mode switching, which will effectively enhance the implementation effect of switching control strategy, and play important role in achieving the seamless switching control of micro-grid operation modes.

Abstract: The traditional digital control system generally adopted wired communication, and the operator panel and display system were usually separate, thus having adverse effect on production efficiency. In this study, a wireless visual control system based on microcontroller unit (MCU) was designed, which included a wireless router, a USB webcam, ATmega8L MCU, MG995 servo, and C # language development. This system not only achieved the goals of visual monitoring and control of industrial production by integrating the control panel and display system, but could also improve production and save the cost of industrial energy consumption. The system has been applied in energy-saving control system of thermal power plants.

Abstract: In this paper, a new method that extracting and fixing load characteristic curve in the power system network state estimation is proposed, based on the combination of The data mining technology in the critical meams assorts algorithm and effective index standards. In the course of the study, this paper put forward a new algorithm ,which simulates used matlab software programming and combined with the actual load data, and extracts load characteristic curve for amended. Revised characteristic curve will serve as a typical load model used to add system state estimation of pseudo measure. The simulation results fully support that the proposed method is rational and effective.

Abstract: Multi-microgrid extended from the concept of Micro-Grid (MG), with the rapid development of MGs, in which case, the interconnection between MGs brought new benefits technically and economically. In this paper, the control strategy of MG will be discussed respectively in the stage of before interconnecting, interconnecting, and after interconnecting. Then, simulation by PSCAD is operated to verify the correctness of proposed control strategy.

Abstract: In rural region, the electrical load increases rapidly as the living standards there improve steadily. Due to reasons such as large radius of power supply and high electrical loss during power transmission, however, the terminal voltage turns more and more unsteady, which affects customer satisfaction greatly. Compared to changing the architecture of the current power supply network, applying the voltage and reactive power unified regulators costs less time and money and it can timely relieve pressure in providing steady power supply in rural region and increase customer satisfaction. In this paper, several technical indicators of the voltage and reactive power unified regulator were estimated firstly. Secondly, a new topology was proposed to suit need of rural distribution network and an analysis was made to the detailed topological structures this regulator and its operation control strategy. Finally, a simulation model was built up to test the working accuracy of the regulator. The simulation results verify the accuracy and feasibility of this new unified regulator.

Abstract: Wireless Sensor Networks (WSNs) play more and more important role in all kinds of applications. Because of its characteristics, energy consumption is an open issue in research field. In LEACH Cluster Head (CH) is selected randomly without any parameter, such as node energy, distance. There exists a probability that energy consumption is unbalanced in WSN, which causes shortening its lifetime. In this paper, we proposed a new LEACH-based protocol, Energy Weight LEACH (EW-LEACH). The main purpose of EW-LEACH is to provide important parameters, node energy, to determine the CH selection strategy. Node energy acts as a weight to alter the probability that a node becomes CH. The results of simulation show that EW-LEACH increases energy efficiency and prolong the network lifetime.

Abstract: Fault detection, isolation, and fault diagnosis for a synchronous generator is a desirable feature that could aid in better monitoring and automation of the machine behavior, and could have a significant impact in establishing an adequate maintenance schedule that ensures proper operation while taking into consideration cost and risk of having a large generator and its maintenance. This work looks in parameter estimation’s algorithm methods those can used in fault detection, isolation and diagnosis. In a broad sense, a fault is understood as any kind of anomaly or malfunction that leads to an undesired performance of the system under consideration.