Advanced Materials Research Vols. 614-615

Abstract: We contrast two shearing mode of the snapshot imaging polarimeter. The numerical simulation proves that the carrier frequency and the spatial resolution of the axial shearing is twice higher than those of the diagonal shearing. This will provide the guidance for our design of the optical instrument.

Abstract: The optical current transformer is an important content in smart grid research field. When the Faraday DC optical measurement system was used in DC current measurement, the low frequency noise caused by photo detector and measured signal were overlapped, which makes the measuring accuracy decrease. To solve this problem, the noise of photo detector is analyzed. Then, the frequency modulation is proposed for spectrum shifting. Furthermore, the principle of modulation method is deduced in formula, and the characteristics of deferent frequency are also analyzed. On this base, modulation signal source is designed. With LabVIEW program, the signal from modulation source is acquainted and analyzed. The results show that this modulation method can realize spectrum shifting and the designed signal source is able to generate waveform needed.

Abstract: Arc fault is one of the reasons causing the common disasters of electrical fire in the distribution system. Therefore, the rapid and reliable detection and diagnosis as well as effective protective measures are needed in order to prevent potential harm due to arc fault. This paper proposes a grille fractal theory-based arc fault diagnosis which calculates the relationship between the adjacent current slope to determine the mutation point of the current or the distortion point of current waveform according to the normal operating current at any time and the various characteristics of arc fault current slope.

Abstract: Multiple high speed CMOS cameras composing intersection system to splice large effect field of view(EFV). The key problem of system is how to locate multiple CMOS cameras in suitable position. Effect field of view was determined according to size, quantity and dispersion area of objects, so to determine camera position located on below, both sides and ahead to moving targets. This paper analyzes effect splicing field of view, operating range etc through establishing mathematical model and MATLAB simulation. Location method of system has advantage of flexibility splicing, convenient adjustment, high reliability and high performance-price ratio.

Abstract: Dissolved Gas Analysis (DGA) is a popular method to detect and diagnose different types of faults occurring in power transformers. Improved three-ratio is an effective method for transformer fault diagnosis used in recent years. This paper applies appropriate Artificial Neural Networks (ANN) to resolve the online fault diagnosis problems for oil-filled power transformer based on improved three-ratio. Because of the characteristic of improved three-ratio boundary is too absolute, a method using fuzzy math theory to deal with the data of the neural network input is also proposed. A major kind of neural network, i.e. radial basis function neural network (RBFNN), is used to model the fault diagnosis structure. In addition, to improve the convergence speed, an improved gradient descent algorithm is used in training RBFNN. Through on-line monitoring the concentrations of the dissolved gases, the proposed diagnostic system can offer a way to interpret the incipient faults. The simulation diagnosis demonstrates the effectiveness and veracity of the proposed method.

Abstract: This paper proposed a railway wagon anti-theft system based on ZigBee technology. The system was consisted of Handheld device, Router and End device. The Handheld device was mainly used for the configuration of the net and initialization. The Router was used to relay the message between the Handheld device and End device. The End device was a monitoring node. The CC2430 microprocessor was the controller of the system. The magnetic sensor was used to monitor the status of the wagon door. The alarm information would be transmitted to the Handheld device to display and alarm. RFID technology was used to mark the number of train carriages. In addition, GPRS module was used for transmitting the wagon information to the remote PC, and finishing wireless long-distance monitor. The experiments verify the reliability of the system. It is proved that the system has a certain application value.

Abstract: For a typical Full-hybrid electric vehicle (HEV) layout, such as Toyota Prius, the power-slit device (PSD) is a key component. Determination of volume or weight of a PSD is an important issue in preliminary design of power transmission applications. The purpose of this paper is to preliminary design of PSD gear drives by minimizing volume of gear trains. A stochastic approach Genetic Algorithm (GA) was applied to a differential-based coupling PSD design problem. Static and dynamic penalty functions were introduced to the objective function for handling the design constraints. The calculation of quadratic mean deviation and dynamic bounding parameter values such as determination of crossover and mutation parameter values were adopted to ensure the convergence of the fitness function. The optimized design method based on GA produced quite well results, which promptly supplied preliminary design parameters of gear drives for differential-based coupling PSD design.

Abstract: The analysis and calculation of short-circuit fault of power system is an important task for the programming, designing and running of power system. With the rapid growth of power system, the traditional ways and means can not satisfy the needs of power system, so it is necessary to use computer to simulate and calculate. Firstly this paper analyzes all kinds of short-circuit fault of a single source power system and then this paper simulates this system, sets the system parameters and fault types, finally calculates the fault current and voltage by MATLAB and the results of the simulation verifies the correctness of analysis above. It avoids the commonly programmable language to set a complex model ,making the fault simulation experiment and data analysis fast and accurate.

Abstract: Maximum Power Point Tracking (MPPT) method is an important technology to improve the system efficiency of PV power generation system. This paper analyzes the methods and the principle of the MPPT. It proposes the mean of the incremental conductance to achieve the control strategy of the MPPT. The simulation study of boost circuit applied in the MPPT is completed based on Simulink simulation model. Based on those researches, this thesis can reduce the main drawbacks commonly related to the other method, at the same time, the simulation results verify that the novel MPPT algorithm can track PV array’s MPP efficiently and keep the system stabilize. The simulation result shows the validity of control strategy proposed.

Abstract: The magnitude of transformer vibration is influenced by that of voltage and current, which might lead to the wrong results in detecting the fault of core and winding by vibration analysis method. Based on the generation machnism of vibration signal, a transformer tank model was presented in this paper. It concerned about the relationship between the vibration (core vibration and winding vibration) and the operating parameter (voltage and current). The experiments were conducted in lab under different voltage and current, and then the vibration model was set up. Furthermore, this vibration model was also used to detect the simulated turn-to-turn short-circuit fault on windings. By comparing the vibration magnitude calculated by the model with the measured one, the defect condition of transformer was confirmed, which verifies that the vibration model presented in paper is effective.