Applied Mechanics and Materials Vols. 347-350

Abstract: With the rapid development of China's high-speed rail construction, accidents caused by lightning are more frequent. How to achieve a more effective lightning protection and grounding is the urgent problem to be solved currently. A two-parallel-connecting-ground-wire transmission line model with the distributed parameter of electromagnetic coupling would be built in this paper. In this model, the connecting ground wire would be defined as horizontal infinite length grounding body. The own distribution parameters of segmented conductor and the parameters of the electromagnetic coupling between the parallel segmented conductors are calculated, based on the theory of electromagnetic field to select the appropriate segment size. Based on this transmission line model, the electric potential distribution of the different positions on the two parallel connecting ground wires is calculated by using the electromagnetic transient calculation software ATP-EMTP. Comparing the calculation results in this paper and the simulation results in the simulation software CDGES, it would demonstrate that the electromagnetic coupling distributed parameter transmission line model in this paper is consistent with the actual situation and it could be used to analyze the electromagnetic coupling effect between the two buried parallel connecting ground wires.

Abstract: A guide microscope is an important part of a certain photoelectric automatic tracking system, and the angle informations acquisition, processing and transmission are the keys for using the guide microscope. According to the application requirements, a kind of angle information processing system of the guide microscope based on STM32 is designed. This system uses the high-performance STM32F103 as the control core and realizes the angle information acquisition, display and transmission by photoelectric encoders, OLED display and RS-485 bus. Then, the hardware design and software debugging are further explained, that it has the simple circuit and convenient development. The running results show the design has the stable and reliable performance. It can meet the requirements.

Abstract: According to the characteristics of power planning, select four key planning scenarios, calculate the initial probability and simulation probability in sequence, and thus calculate the scenario probability. Define the screening considering the scenario probability and incidence of evaluation factor index for the typical scenario. In the decision-making process, the fuzzy decision method of interval numbers based on trapezoidal membership function is used to calculate the scheme membership, which overcomes the difficulty of precise calculation problem for planning index. And according to maximum membership degree for sorting, finally obtaining quality comparison results of the scenarios. As an example of a "twelfth five-year" planning of one city, an integrated decision making of power planning is developed, the simulation results show the scientificity and rationality of the method.

Abstract: Low-carbon economy has become a development trend in the international energy sector. Our national electric power industry as a part of the energy sector has to change the power structure in order to follow this climate. In this paper, from the perspective of cost-benefits, based on the analysis of impact of the indicators of the power structure, we establish a index system of the planning low-carbon power structure. Combined with the method of analytic hierarchy process, we re-plan the traditional power structure. Finally quantify the distribution proportion of the thermal power, hydropower, wind power, nuclear power and solar power.

Abstract: By revised method of fitting magnetization curve in segment, technique of simulating the nonlinear characteristic of laminated core is enhanced. The DC-bias problem is computed based on the time-domain magnetic-circuit coupled model while considering the saturated and unsaturated magnetizing characteristics of the laminated core. Experiments are designed to verify the validity of the proposed method, and then the volt-ampere feature of unsaturated magnetization is learned. Consequently, the results indicate that the improved method is more accurate and efficient by contrast.

Abstract: The wind power, which enjoys the most mature technology and the most common commercial application, plays an important role in optimization of power supply structure and carbon release reduction. This is to analyze the influence of wind power integration on the power grid in terms of electric power quality, capacity of short circuit, power stability, power generation planning and dispatching etc. and propose increasing the bearable capacity of wind power by power grid by means of optimizing power supply structure, constructing strong power grid, choosing reasonable types of wind driven generators and reactive compensation equipment and completing relevant laws and regulations about wind power integration to power system.

Abstract: Load characteristic is one of the vital factors that effect the stability of voltage of power system. As the most important dynamic load in power system, induction motor is one of the most direct reasons which resulting in instability of voltage. In simulated analysis, the establishment of load model, choice of parameter as well as ratio distribution of different kinds of load will lay considerable influence on the stability of system. This thesis establishes the load model of induction motor in stable and transient state and simulates on the basis of Shandong power grid. As the simulating result shows, load ratio of induction motor has fundamental effect on the voltage stability of Shandong power grid. As the load ratio of induction motor increases, the stability of voltage of Shandong power grid decrease and the voltage may even break down.

Abstract: This paper focused on power system security problems and proposed risk assessment and preventive control method of electric power system based on voltage risk. The method built up a system voltage risk indicators, and have system voltage risk identified through risk assessment, on this basis, reduced the risk of the system voltage by optimizing the control variables of the system, which of course can increase system security. Finally, Refers to a 5-node tests as examples to verify availability of this method.

Abstract: This paper has discussed the treatment of uncertainty in the market environment, using chance-constrained programming to describe the risk and Monte Carlo simulation method to calculate the risk factor, the risk factor is bound to establish transmission network flexible planning model, the result is a transmission planning of minimum comprehensive cost under uncertain environment for the future program.

Abstract: The work interests in the two-way opportunistic relaying (TWOR) system in which the analog network coding (ANC) employed. For the TWOR-ANC, we first present the traditional max-min best relay selection scheme as well as the corresponding closed-form analytical expressions for the cumulative distribution function (CDF) and the probability density function (PDF) of the end-to-end SNR. Then, to simplify the analysis of system performance, by using the approximation of the modified Bessel function of the second kind, , we obtain the performance bounds of the TWOR-ANC system. The analytical results show that e^-z/z determines the lower bound of system performance, and the exact solution of system performance is very close to the lower bound in low SNRs. At the same time, 1/z does the upper bound, and the exact solution is very close to the upper bound in high SNRs. Thus, in high SNRs or lower SNRs, the system performance can be measured approximately by the upper bound or lower bound.