Advanced Materials Research Vols. 1092-1093

Abstract: The development history of fracturing fluids is reviewed, the compositions and action mechanisms of the clean fracturing fluid systems used currently are analyzed, the recent research and application of the clean fracturing fluids in coal—bed methane production are summarized, and the development trend of clean fracturing fluids is presented in this paper.

Abstract: In this paper the fractures appeared in the surface of nanoparticle silicon anode for lithium-ion batteries was explored. The changes of nanoparticle silicon anode before and after cycling were charactered using SEM, XRD,Cyclic voltammograms (CV) and electrochemical impedance spectroscopy (EIS). The result indicates that the electrode cracking occured in the cycling process , the CV, EIS and discharge specific capacity curves proved the fractures could lead to the degradation of the electrochemical performance.

Abstract: Gas hydrates are a major concern in oil and gas industry, Gas hydrates form in small amounts of water, gas, and the appropriate pressure and temperature conditions. Gas hydrate storage and transportation technology starts a new way for energy storage and transportation industry. The most critically technical problem is how to improve the hydrate formation rate, storage capacity and form continuously. The influences of surfactants on induction time in three types of solution with equal concentration were studied by means of visual hydrate experimental equipment, and generalized induction time was measured by direct observation method. Specific effects of different surfactants on hydrate formation were summarized, as well as the hydrate formation mechanism of surfactants . The lack of research and the research direction of the future were concluded . The further study of surfactant mechanism and build kinetics model containing surfactant have important theoretical value . The result shows that the gas molecules saturated due to the solubilization of surfactant, which promotes the progress of mass transfer in the hydrates. And driving force is provided for the complexation of host molecules and guest molecules during the formation progress of gas hydrates.

Abstract: ADRC is Active disturbance rejection control,it inherits from proportional–integral–derivative (PID) the quality that makes it such a success: the error driven, rather than model-based, control law; it takes from modern control theory its best offering: the state observer; it embraces the power of nonlinear feedback and puts it to full use; it is a useful digital control technology developed out of an experimental platform rooted in computer simulations. ADRC is made possible only when control is taken as an experimental science, instead of a mathematical one. It is motivated by the ever increasing demands from industry that requires the control technology to move beyond PID, which has dominated the practice.

Abstract: LGJ150/25 steel core aluminum stranded wires were selected as the test wires, and the aeolian vibrations which work in different cycle times of wire that is under the conditions of dry and acidic corrosion were simulated by the self-made test bed. The electronic number of corona discharge of each pre-set conductor was measured, when applying AC high voltage on the wearing wires step by step,so that the corona inception voltages of the conductors could be confirmed. And the effect of the vibration cycle times and environmental conditions on the corona discharge was researched. Taking the sum of all aluminium stands wear area of a pre-set wire as the fretting wearing capacity, the relationship between the wire wearing capacity and the corona discharge was studied. The results indicate that the corona inception voltages of the conductors decrease with the increase of the cycle times and the wires wear capacity. In general, the wear capacity of the acidic corrosion conductors is larger, and its corona inception voltage is lower. Therefore the decrease of the conductor fretting wear can effectively reduce the corona loss of transmission lines and other hazards.

Abstract: It is difficult for current technical standard to satisfy the development requirement of smart distribution network because the new systems of distribution generation and energy storage and the new requirement of distribution network. First, new requirement for technical standard is analyzed in this paper. Then, applicability evaluation model of technical standard in smart distribution network is built. At last, empirical research on applicability of the operational control specification of the interconnection of distribution generation to power grid is carried out. The results show that the evaluation method proposed in this paper is feasible and effective.

Abstract: This paper discusses a phase component calculation model of current distribution on OPGWs when asymmetric fault occurs. The calculation is based on analysis of electric and magnetic environment and experience of actual engineering projects. Influences of some factors such as the operation mode of OPGW and resistance of power tower are mentioned to find out their influence on fault current distribution. These are applied in an actual engineer project. The calculation method is benefit for the verifying and selecting of OPGW.

Abstract: This paper proposed the line-commutated converter based multi-terminal HVDC (LCC-MTDC) combining with the static synchronous compensator (STATCOM) for doubly-fed induction generator (DFIG) based wind farms integration with bulk wind power transmission over long distance. This paper is aimed at the control strategy design and the operational characteristics research of LCC-MTDC for wind power transmission. Then, the control methodologies of the complex integration system are addressed from two aspects: the MTDC and the wind farm. The coordination control strategy is developed to ensure the stable operation of the MTDC system and the wind farm controller is designed to capture the maximum wind power and ensure all the wind power transferred into the MTDC. Simulation results in PSCAD/EMTDC show that LCC-MTDC could achieve desirable operational performances with the control strategy proposed.

Abstract: Shunt Active Power Filter (SAPF) is a new device for compensating harmonic currents in power system [1]. For unbalanced three-phase four-wire circuits, it need detect the total of harmonic and fundamental negative sequence and zero sequence currents at the same time. Base on traditional method of ip-iq, a detecting method which is suitable for unbalanced three-phase four-wire is proposed and analyzed by mathematical reasoning. At last, correctness of the result is verified by simulation.

Abstract: This paper introduces the origin of situation awareness and its application in many fields. Through the analysis the application results in other fields, we conclude that the situation awareness technology can be applied to power system analysis, monitoring distribution operation, disaster warning and so on. It is an indispensable part of the smart grid implementation.