Advanced Materials Research Vols. 1070-1072

Abstract: ZnO-based varistor ceramics with different recipes were prepared in this research. It was found that the grain growth was restrained with the addition of Ba²⁺. SEM results indicated that the grain size of ZnO varistor ceramics with Ba²⁺ was reduced to 4.7 μm. Correspondingly, the breakdown electric field of the ZnO varistor samples were extremely enhanced to 8730 V/cm. The results of ac conductance response showed that two relaxation peak 1 and 2 with activation energy at about 0.24 eV and 0.36 eV were observed in 100-250 K, which were not affected by additives. However, a new conductance relaxation peak 3 in 300-450 K for sample B and C can be found, whose activation energy were varied from 0.55 eV to 0.65 eV with the addition of Ba²⁺. It was put forward that the electrical properties of ZnO varistor ceramics may be associated with the conductance relaxation peak 3.

Abstract: In this paper, a intermediate compound of solar cell materials and plant activator was reported. 4-hexyl aniline as the raw material, through a series of reactions to get a new compound E and characterized by ¹H NMR and IR. This compound has excellent solubility in common solvents and as a promising candidate of synthesizing organic solar cell materials and plant activator.

Abstract: As the third generation solar cells, quantum dot sensitized solar cells (QDSSC) has received wide attention from researchers because of its high theoretical energy conversion efficiency and low production costs. The preparation of CdS quantum dots for TiO₂ inverse opal based QDSSC by successive ionic layer absorption and reaction (SILAR) was investigated. The optimized number of SILAR cycle and ionic reaction time was obtained by the analysis of absorption spectra.

Abstract: On-line temperature monitoring provides the means to evaluate the state of equipment and timely detect abnormality. However the power source of temperature sensing units, including sensor, transceiver and microcontroller, is not perfectly ready. In this paper, a monitoring device is proposed based on resonant coupling wireless energy supply. One feasible structure of the device is present. The device includes two parts. One is the measurement module which is placed on the high potential part, the other one is the processing module which is placed on the low potential part. The power and transfer distance demand of the measurement module is analyzed. Then a wireless power transfer system is designed to fulfill the need. A prototype system is founded to confirm the validity of our design. The results show that the device can work normally while the measurement and the processing module is 10cm away from each other, which means the proposed system is practicable. The EMI and other characteristics will be studied in the following work.

Abstract: Power transformer is a extensively-used electrical equipment in our national economy. Generally speaking, there exists 6~8 times of transformation from electricity generation, power supply to power utilization. As is known to all, transformer itself generates power loss, so, because there are so many transformers and the whole capacity is very big, the economic operation of transformers proves of great importance. This article finds effective energy-saving method by analyzing a mode of busbar-line transformer economic operation. In the end, a practical case is added to prove the correctness and validity of this mode.

Abstract: Reasonable black-start scheme is of great significance to power system restoration. The entropy method and improved analytic hierarchy process algorithm are applied in evaluation indexes determination. Compared to the traditional algorithm, it takes into account the objectivity of reality and the subjectivity of human experience and adjusts both relative importance by a impact factor. It dose.t need the optimization calculations. At the same time, the fuzzy consistent matrix is applied to improve the traditional analytic hierarchy process, avoiding the consistence problems. Finally, compare the pros and cons of each program by calculating the comprehensive evaluation index to achieve the program’s full sort. The calculation process is simple, the efficiency is obviously improved and the availability of the method is validated through an example.

Abstract: Multi-objective optimization model on sitting and sizing of Distributed Generation (DG) was proposed in this paper, and it was based on the comprehensive consideration of total system network loss and total deviation of node voltage, aiming at the optimization of DG’s access, the simulation tests were carried out on the 13 bus test system using Particle Swarm Optimization (PSO) algorithm that belonged to swarm intelligence algorithm, receiving the improved network loss and node voltage as the evaluation index, the mutation operator was introduced into the basic PSO algorithm, which improved the possibility to find a more optimal value ,the results showed that IPSO algorithm had strong global searching ability and rapid convergence speed for optimal allocation of Distributed Generation in the distribution network, and it created a new idea for further Distributed Generation allocation.

Abstract: Research on the power flow transferring identification method based on DC sensitivity factors is carried out. According to the analysis of transfer power flow sensitivity factors matrix, the disadvantage of this method is proposed that it may identify incorrectly due to the only criterion of active power when fault occurs. In order to improve its performance, the criterion of impedance angle is put forward. The combination of the two criteria is applied to the improved flow transferring identification scheme. The improved scheme can identify non-faulted overload reliably and block zone 3 distance protection to prevent cascading trips effectively. The simulation results of IEEE 10-machine 39-bus system have proved its superiority and practicality.

Abstract: Transient saturation characteristics of TPY-type current transformer have great impact on the right action of line differential protection. This paper proposes an analytical method of line differential protection under current transformer saturation by utilizing current transformer model and test methods. The true current value of primary side can be obtained by our proposed method and therefore it yields correct assessment of line operating status. This method has high reliability applying to practical engineering examples of differential protection.

Abstract: Fault location method based on multi-source fault information in repair of distribution network is proposed to make the precision and speed of fault location higher. Firstly a topology description and storage method which is appropriate to distribution network fault location is proposed. Then, based on the topological structure of distribution network, fault information on the distribution network is integrated processed. Fault information grouped and priorities are identified using the association of distribution equipment. Low-voltage fault location is achieved by applying fuzzy set theory in fault message omissions and misstatements situations. Finally, an example demonstrates the effectiveness of this method.