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Thioglycolic acid (TGA)-coated colloidal Ag2S quantum dots (QDs) emitting in the near-infrared (NIR) region upon excitation by an 808 nm diode laser were synthesized. The observed photoluminescence (PL) was attributed to the presence of ligand-modified Ag2S on the QD surfaces and could be easily controlled by a simple dilution process due to the concentration-dependent surface structure of the colloidal QDs. Upon dilution of the solution, the PL intensity initially increased before later decreasing, with a blueshift being observed in the PL spectra. These phenomena can be accounted for by the aggregation of QDs due to a decrease in the content of ligand-modified Ag2S on the QD surfaces upon dilution, which in turn affected the fluorescence resonance energy transfer (FRET), and re-emission of the surface energy level.

It is an important part for the power system operation risk control to identify the critical lines. Fluctuation of wind power and fluctuation of load will have a great influence on power transmission and distribution, which will lead to the change of critical lines. Based on probabilistic load flow (PLF) analysis, the risk theory is introduced to put forward, and probabilistic flow betweenness considering uncertainty of wind power and load is presented for critical line identification, which reflects the influence of power grid structure characteristics, change of system running state and uncertain factors on power transmission. It can identify critical lines more accurately. Simulation calculation on CEPRI-36 bus system integrated with wind farms and IEEE-39 bus system with wind farms verify effectiveness of this method. It is able to search for the critical lines according to system running state in actual application, so as to adopt security control measures for the system.

The optimal charge and discharge schedule of EVs is studied under distribution network considerring wind power. Markov decision process is adopted to model the randomness of supply and demand. Two-level scheduling model of electric vehicles with electric vehicle agents are adopted. The electric vehicle agents are responsible for collecting the real-time charging-discharging demand of electric vehicles in the region and reported to the upper dispatching center. The goal of the upper dispatching center considers the power losses in the distribution network, load variance and the matching degree between EV charging-discharging and wind energy. The goal of the lower agent considers the EV charging-discharging fees and EV charging battery losss costs. When deciding the optimal charging strategy, two-level Rollout methodis adopted considering the the effects on future decisions by the current decisions. Finally, the optimal results under four different strategies are simulated on the IEEE 30 nodes distribution network system.

Accurately mastering the capability of wind power accommodation is conducive to construction planning of wind plant and provide auxiliary to dispatching decision in actual operation. Based on deep analysis of key factors influencing accommodation capability of wind power basic idea and method were proposed to manoeuvre wide and flexible adequacy resources involved in system regulation. Comprehensively considering technical characteristics of various power generations and such constrains as the balance of power and thermal loads and transfer capacity and taking the maximum accommodation capability of new energy as objective function, a model is built to analyze new energy accommodation capacity of power grid. Taking shanxi province in China, which is rich in new energy resources, as calculation example, the changes of new energy accommodation capability were simulated and analyzed under different scenes of introducing in different flexible resources.

A large number of wind farms access power system, which will bring new challenges to the security and stability of the power grid, because the stability of the power system is greatly influenced by the dynamic performance of the wind turbine. This paper describes a performance appreciation method of wind farm, which is proved practical and effective by the measured data of the wind farm.

The voltage of power grid will drop when the units pump water in the pumped storage power station.This paper uses the method of simulation and field test to study effect of reactive power regulation on the power grid in the pumped storage power station,which will provide reference for voltage regulation of pumped storage units and meet the peak load regulation of power grid and acceptance of wind power requirements.

This paper introduced several types of distributed wind turbines, discussed the impact on grid-connected and put forward the measures. Combined with the wind data in Shanghai area, economy of the currently used widely distributed wind power generator was calculation. The results show that, the distributed wind power generator had better stability and economy, suitable for application in the surrounding areas of the city.