Applied Mechanics and Materials Vols. 448-453

Abstract: As the urbanization in China accelerates, metropolitan regions are tending to change their spatial expansion mode from traditional satellite city mode to city cluster development strategy. Under this situation, the paper proposes the method and steps of evaluation for urban distribution network in city which takes the city cluster development strategy. The method takes city cluster as the unit of network planning and evaluation, firstly analyze the functional orientation and the land allocation of the target cluster for evaluation, then take other clusters with the similar function in other metropolis by analogy, finally a more instructive evaluation index system and evaluation standard will be obtained. The practical application in the medium voltage distribution network of Mazhai Industry Park in the city of Zhengzhou has proved that the method proposed is able to meet the demand of practical work in distribution network evaluation under new situation.

Abstract: As the urbanization of cities is rapidly developing in China, metropolitan regions establish the clustered power network planning scheme on the background of the clustered city planning of the adjacent areas. Base on the functional orientation and difference of clusters, as well as the theory of hierarchical clustered city planning, the article puts forward the power network planning thoughts and methods. As cluster becomes a planning unit, the load density method is applied in the differential load forecast and the location of substations as well as the path of transmission lines is selected with the thoughts of separation according to different layers and areas. And then, the results will be compared and verified with the planning scheme of the other clustered cities which have the similar function orientation and planning strategy. Finally, the planning methods will be standardized. The application in the power network of Cluster of Livable Education City in Zhengzhou has proved that the methods and steps of the power planning method proposed is able to meet the demand of the network development under the situation of the rapid growth of load.

Abstract: Large scale integration of renewable is still very challenging due to their intermittency and fluctuations. Aimed at this problem, this paper establishes an evolutionary game model to analysis the dynamic evolution of interests cooperation between the wind farms corporations and the power grid corporations. Then, this paper discusses the relation between multiple variables, such as price of the conventional energy power rate of the subsidy marginal cost of the initial invention and coefficient of distribution of excessive profit, and also analysis how these variables affect the Evolutionary results of this system, based on different replicator dynamics and evolutionary stable strategies. Being at the end, this paper has identified a fair and reasonable distribution coefficient of excessive profit. After equilibrium analysis, a win-win operating mechanism was established to guide the various stockholders to tend to co-operation correctly. Finally, some countermeasures and suggestions were proposed for wind power integration.

Abstract: Distribution system reliability calculation models and assessment methods would change while connected with distributed generation. A reliability analysis method for distribution system with distributed generations was proposed in the paper, which makes an improvement of traditional distribution network minimum cut set method, and the characteristics of distributed generation and distribution network element reliability models are considered. Functional role of distributed generation in the power distribution system failure and distributed power adapter with load strategies were also analyzed in this method. Case simulation analysis was used to verify its effectiveness.

Abstract: In this paper, a multi-objective optimal planning design model including net cost, loss of capacity and pollutant emission in a life cycle was presented for a stand-alone microgrid system with diesel generators, wind turbine generators, photovoltaic generation and lead-acid battery. In this model, the two coordinated operational strategies between diesel generators and battery, the dispatching method for diesel generators, and the reserve capacity were considered. The type and capacity of distributed generation units were selected as the optimal variables. The optimal allocation of distributed generation units and battery for an island microgrid system was carried out under the different combination objectives and control strategies by the self-developed software (Planning Design System for Microgrid, PDMG).

Abstract: Determining harmonic contribution quantitatively at the point of common coupling is an important task for power quality management. Outliers and influential points could have strong influences on regressors. This paper puts forward a method named reweighted complex least squares to eliminate or reduce the influences to ensure the robustness of the regression. The method can improve precision of the equivalent harmonic impedance and it can get a more reasonable result in harmonic contribution determination than previous methods. A case study based on the IEEE 14-bus test system was conducted, which shows the validity of the proposed method.

Abstract: Power quality and power marketing are comprehensive concept contains multiple indexes. This paper builds the index system of the power quality promoting the power market development. And the structural equation modeling (SEM) be used to calculate the impact factor of power quality to marketing at different times and areas. This paper firstly puts power quality and marketing which are regarded as latent variables. And select the power quality index that includes the amplitude, frequency, spectrum, modulation, the notch depth and marketing index that includes market share, electricity consumption per capita, customer satisfaction rate, install electricity rate, customer loss rate as measured variables of latent variables, and establish the causal influence path graph of power quality and power marketing. According to the path graph, which reflecting causal relationships among the latent variables and the measurement equation reflecting relationship between the latent variable and significant variables. To test the significance and the rationality of the parameter and evaluate the overall performance of the structure equation model. Finally, according to the path graph and the path coefficient, we get causal influence coefficient between the power quality comprehensive index and power marketing comprehensive index.

Abstract: Given the characteristics of power distribution grid project including the huge amount of investment, long construction period, long investment payback period and so on, the precision of investment estimate has a tremendous influence on decision making, economic effect and cost control in each stage. By way of introducing the current situation of investment estimate of power distribution grid project, and analyzing the key factors affecting the investment estimate precision including investment decision-making and management, project design plans, risk and the investment estimate preparation, this paper puts forward improvement strategies aiming at influencing factors in order to promote the rapid development of power distribution grid project in Inner Mongolia.

Abstract: This paper establishes a power planning model based on minimizing operation and maintenance cost. The model take into account the costs of the wind turbines, photovoltaic cells, batteries, biomass generators, diesel generators, power electronics devices and communications facilities operation and maintenance, credit them in the objective function, and considering some certain constraints, use particle swarm algorithm model, by calculating and, simulating examples , to find the optimal solution, Finally to find the conclusion that to use wind turbines, photovoltaic cells and batteries for electric as much as possible.

Abstract: The development of micro-grid technology provides power system a variety of forms, flexible ways of power supply schemes, but a lot of basic micro-grid operational problems are different from the traditional large power grids, which need to be studied specifically. This paper studies the power planning problem of micro-grid, namely to meets the system operational constraints, study how to optimize the micro-power configuration of micro-grid, so that the whole micro-grid life cycle cost is the smallest.