Advanced Materials Research Vols. 805-806

Abstract: Energy storage plays a vital role in the reliable operation of Micro-Grid (MG) due to its characteristic of running stabilization and control flexibility. It can act as the master inverter and maintain system voltage and frequency stability as MG in off-grid mode under voltage control mode. During the transfer of MG from grid-connected mode to off-grid mode, the PCC (point of common coupling) three-phase static switch cant shut off at the same time. Moreover it needs to match the MG voltage and utility grid voltage when the islanded MG needs to reconnect to the utility grid.In order to solve these problems, a control strategy of grid-connected/off-grid seamless transfer based on energy storage is proposed. Simulation was presented from a MG platform including photovoltaic (PV), wind turbine (WT) and energy storage and the result shows the feasibility of the proposed approach.

Abstract: GICs in technological conductor networks are a ground manifestation of space weather. During severe geomagnetic storms, if GICs flow in power systems, real and reactive power flow will swing abnormally, also transformer saturation, over-voltage fluctuation, frequency shift, unnecessary relay trippings and increased harmonic contents, even damage of transformer or a collapse of the whole system may occur. So GIC controlling in power systems is so significant that it can help power systems stand through strong geomagnetic disturbances, as well as ensure safe and stable operation of power systems. In this paper, control methods and techniques on GIC in power systems have been summarized in reference of research achievements and control experience on GIC.

Abstract: This paper calculate the transmission loss caused by generation right trade and its impact on system based on the DC power flow equation. This method takes into account each power flow state and more accord with the practical situation of generation right trade. By analyzing the mechanism and process of generation right trade, to the unreasonable method that averagely allocate the trading power in trading hours under the daily generation right trade mode, this paper propose a method to fit a trading power allocation curve based on cubic spline interpolation and power system. The curve can be adjusted by trading power and replace the traditional averagely allocate method. Combined with three kinds of allocating situation, the rationality of this paper has been tested on IEEE-13 bus system.

Abstract: Based on the current development status of China power system, this article aims to analyze factors that have influence on operations emission reduction capability of regional power system, and develop mathematical model for emission reduction capability measurement. The great potential emission reduction capability will be calculated by applying this model to Jilin Province.

Abstract: An improved reactive power optimization algorithm of distribution system is presented, which incorporates distributed generations and running cost. By this method, the comprehensive cost can be reduced to the potential minimum value. Firstly, based on the function between the operations of preliminary main equipments and the comprehensive cost, the optimization model is presented to reduce the comprehensive cost. Secondly, the traditional back/forward sweep method is improved by updating DGs reactive power amount during each iterative step timely. The changing value is gained according to the voltage deviation amount. Thirdly, a novelty hybrid PSO algorithm is presented, which can adapt binary variables and discrete variables in unison. Lastly, the algorithm is realized on the platform of VC++ 6.0 and the case study is done. The results have proved that this method can reduce the comprehensive cost and the optimization problem can be solved quickly.

Abstract: The rapid development of smart grid in China has put forward higher requirements to the power grid dispatch, and it is necessary to develop adaptable smart grid dispatch support system. Based on the existing technical achievements of smart grid dispatch, a power grid operation track oriented automatic smart dispatch system is proposed to accurately grasp the trend of grid operation status. The concept and characterization method of grid operation track are introduced. The overall objective of automatic smart dispatch is presented. And the framework of automatic smart dispatch system is proposed, mainly including awareness & forecasting, analysis & assessment, decision support and automatic control. Moreover, the key technologies of automatic smart dispatch are pointed out.

Abstract: A power R&D process can be regarded as a jump process of scientific knowledge full of exploration and complexity. Every jump represents a scientific breakthrough or a new discovery in this setting. In this paper, the inter-arrival times are treated as random variables observe arbitrary distributions. The ɑ-optimistic net return of project performance is proposed and a chance-constrained programming model is established to model the power R&D optimal stopping decision problem. Considering the complexity of the model, the stochastic simulation is designed to estimate the values of project return performance and the simultaneous perturbation stochastic approximation (SPSA) algorithm is employed to solve the proposed model. Finally, the effectiveness of the hybrid algorithm and the applicability of the model are illustrated by numerical examples.

Abstract: Access distributed power will take great influence to distribution network's safe and economic operation. This paper established a distribution network planning economic model and analyzed the advantages and disadvantages of various planning algorithms, and propose an adaptive parallel genetic algorithm. This algorithm can overcome premature phenomenon of standard genetic algorithm, and the ability is better to seek the global optimal solution.

Abstract: According to characteristics of the power grid in China, a framework of microgrid for distributed generations (DGs) integration is proposed. To ensure the reliability of power supply, the framework access distribution network by single-bus section. The DGs consist of photovoltaic (PV) system, wind power system and energy storage system. Based on the proposed framework and control strategy, the models of distributed generations were built in DIgSILENT/PowerFactory. According to the control strategy, three cases were analyzed: 1) the dynamic operating characteristics of the microgrid from grid-connected mode to isolated mode; 2) the dynamic operating characteristics of the microgrid with wind speed fluctuation disturbance in grid-connected mode and islanded mode; 3) the influence to microgrid operation in different fault types and locations. The simulation results show that the proposed framework of microgrid conforms to Chinas power grid feature and the control strategy can ensure safety and reliable operation under different situation.

Abstract: The substation process level networks modeling based on OPNET provides the solution for the quantitative assessment of process level networks. To meet the demand in substation automation system application, it analyzes the modeling requirements of entity equipment, IEC 61850 standard and optimization strategies. From the prospective of OPNET operating system, model library and user-defined modeling methods it researches the adaptation of OPNET and process level networks modeling, and it analyzes the substation process level network modeling based on OPNET with the demonstrations of SV/GOOSE, merging unit and protection IED, VALN modeling, providing the solution for the quantitative assessment of process level networks. Finally it proposes the modeling and simulation platform for quantitative assessment of process level networks in substation basing on an 110kV substation. This paper provides an effective tool for the quantitative assessment of process level networks and substation automation system.