Applied Mechanics and Materials Vols. 448-453

Abstract: Wind power is an important type of renewable energy sources. In this passage we will apply Life Cycle Assessment (LCA) to analyze the four stages of wind power generation,which are production of raw materials, transportation, build-operate process of wind plants and demolition stages, calculate the energy consumption and the environmental impact, set a contrastive analysis between coal-fired power plants and wind power plants. We will take WangHaiSi Wind Plant in Faku, Shenyang as an example to show the difference between the two ways of getting power. The analysis shows that: in comparison with coal-fired generation, wind power generation saves more energy and reduces emissions of pollutants markedly; the main energy consumption comes from production of raw materials, which takes 79.3% of the total energy consumption throughout the life cycle. In the meantime, the large amount of ecological resources consumption from construction, operation and maintenance of wind plants leads to mass emission of carbon dioxide and sulfur dioxide, which respectively take 67.3% and 96.6% of total emissions. Besides, wind generation only accounts for 0.93%, 0.89% and 2.72% of energy consumption, global warming potential (GWP) and acid potential (AP) of coal-fired power generation. Thus, it proved that wind power generation has lesser impacts on environment than coal-fired power generation. However, it is still of great necessity to strengthen the environmental protection measures to reduce the consumption and destroy of ecologic resources.

Abstract: As the core monitoring system of AP1000, BEACON always uses a full-core nodal model for core monitoring based on the ANC-NEM nodal model. The theory behind the nodal expansion method is discussed, and the application of the method in BEACON is described. Finally, an ANC-NEM calculation simulation is proposed.

Abstract: Water/electricity cogeneration system in nuclear power plants and its peaking operation modes are analyzed in this work. The large-scale water/electricity cogeneration system can use the valley nuclear power during nighttime for seawater desalination, which can improve the peaking capacity, decrease desalination water cost and alleviate the water shortage in coastal cities. The peaking operation mode results show that the reverse osmosis desalination system runs better with variable load mode "12-1-10-1" (day 50% - night 100%) under the full load operation of nuclear reactor. In this mode, the peaking capacity of the water/electricity cogeneration system is 33%, the desalination water cost is 3.49 Yuan/m³ and the peaking cost is 65 Yuan/MWh. Development of the large-scale water/electricity cogeneration system in nuclear power plants has multiple benefits in China.

Abstract: Source term is an important input parameter for evaluation of the radiological consequences in the severe accident and can affect the level of emergency response. The research methods of severe accident source term mainly include numerical simulation and experiments inside and outside reactor. The simulation and experiment research progress of the severe accident source term and the results were discussed, mainly including the migration and release behavior of radioactive nuclides in severe accidents, their existing forms and distribution, the effect of engineering measures on the radioactive source term, the sensitivity analysis of parameters, model verification, etc. Finally, the problems needed to be solved in the severe accident source term research currently were proposed, which could be used to provide reference for the further research.

Abstract: A relatively simple model of nuclear power plant was established based on previous detailed models, which can be used in medium-term and long-term power system simulation. Based on the established model, a much simpler model was developed which can be used in transient stability simulation.

Abstract: In order to improve thermal efficiency of nuclear power plant with a pressurized water reactor, this paper analyzed the reason why nuclear power plant runs with a low thermal efficiency, and then pointed out that the conventional operation mode results in a low thermal efficiency for middle and high load regions. A new method was proposed to improve its thermal efficiency by operating nuclear power plant under the condition with a high and constant steam parameter. Two problems encountered by the proposed method were investigated, and the results indicate that it is preferential way to increase flow rate of primary side coolant to boost steam parameter of the rated condition, and it is feasible to maintain steam parameter constant by regulating flow rate of primary side coolant continuously.

Abstract: To make effective fault diagnosis of grounding grid , a new method using Self-Adaptive Particle Swarm Optimization (SAPSO) is proposed. Firstly, the grounding grid can be handled as a resistive network to establish fault diagnosis equations. Then the objective function based on minimum energy principle is added to lower the ill-condition of diagnostic equation. Next, according to optimization techniques, a new method of SAPSO is proposed to solve the corrosion diagnosis equations. The method takes advantage of the high global searching ability of SAPSO to obtain the optimal solution to the diagnosis model. By means of the analysis of the simulation, the correctness and reliability of the method have been verified.

Abstract: As distribution flexible AC transmission system (DFACTS) technology is an economic and effective means to improve the power quality, the applied DFACTS devices are increasing. Therefore, the interactions among the DFACTS controllers should be considered. The paper establishes the linearized model of a single-load infinite-bus distribution system installed with a distribution static var compensator (DSVC) and a distribution static synchronous compensator (DSTATCOM), and the system transfer function can be obtained based on this model. Then, uses the relative gain matrix (RGA) method to analyze the interactions under different electrical parameters, drawing a conclusion that the interactions w ill be weakened when the electrical distances are increased and vice versa. The simulation results verify the effectiveness of the proposed model and the RGA method.

Abstract: With GIS being widely used, partial discharge detecting and defect pattern recognition become more and more meaningful and important. To realize defects identification of partial discharge map in GIS, a novel method based on Radical Basis Function (RBF) neural network is proposed. Firstly, a model is constructed to simulate the discharge pattern map by the use of random function randint. Secondly, based on the model above, a lot of data which meet the condition can be collected to provide for pattern recognition. Then, a RBF network is introduced to identify the pattern recognition. It can be trained by using the data above. Finally, through changing training error, high correct rate can be got. These indicate that the method is effective.

Abstract: Based on Wagner field cancellation method, the paper presents a simplified method to calculate the induced overvoltage on transmission lines excited by lightning striking on tower. Firstly the square-wave response of lightning-induced voltage is calculated, and then the responses produced by other excitations can be calculated by Duhamel integral. This method can reflect the time-varying characteristic of the induced overvoltage. The simulation results show that the amplitude of lightning current and the length of upward leader have greater impacts on the induced overvoltage.