BackgroundChina’s universal medical insurance system (UMIS) is designed to promote social fairness through improving access to medical services and reducing out-of-pocket (OOP) costs for all Chinese. However, it is still not known whether UMIS has a significant impact on the accessibility of medical service supply and the affordability, as well as the seeking-care choice, of patients in China.MethodsSegmented time-series regression analysis, as a powerful statistical method of interrupted time series design, was used to estimate the changes in the quantity and quality of medical service supply before and after the implementation of UMIS. The rates of catastrophic payments and seeking-care choices for UMIS beneficiaries were selected to measure the affordability and medical service flow of patients after the implementation of UMIS.ResultsChina’s UMIS was established in 2008. After that, the trending increase of the expenditure of the UMIS was higher than that of increase in revenue compared to previous years. Up to 2014, the UMIS had covered 97.5% of the entire population in China. After introduction of the UMIS, there were significant increases in licensed physicians, nurses, and hospital beds per 1000 individuals. In addition, hospital outpatient visits and inpatient visits per year increased compared to the pre-UMIS period. The average fatality rate of inpatients in the overall hospital and general hospital and the average fatality rate due to acute myocardial infarction (AMI) in general hospitals was significantly decreased. In contrast, no significant and prospective changes were observed in rural physicians per 1000 individuals, inpatient visits and inpatient fatality rate in the community centers and township hospitals compared to the pre-UMIS period. After 2008, the rates of catastrophic payments for UMIS inpatients at different income levels were declining at three levels of hospitals. Whichever income level, the rate of catastrophic payments for inpatients of Urban Employee’s Basic Medical Insurance was the lowest. For the low-income patients, a single hospitalization at a tertiary hospital can lead to catastrophic payments. It is needless to say what the economic burden could be if patients required multiple hospitalizations within a year. UMIS beneficiaries showed the intention of growth to seek hospitalization services in tertiary hospitals.ConclusionsIntroduction of the UMIS contributed to an increase in available medical services and the use thereof, and a decrease in fatality rate. The affordability of UMIS beneficiaries for medical expenses was successfully ameliorated. The differences in patients’ affordability are mainly manifested in different medical insurance schemes and different seeking-care choices. The ability of the poor patients covered by UMIS to resist catastrophic medical payments is still relatively weak. Therefore, the current UMIS should reform the insurance payment model to promote the integration of medical services and the formation of a tiered treatment system. UMIS also shoul...

This study presents a new concept for full‐capacity wind turbines (WTs) to emulate inertial response behaviour by optimising phase‐locked loop (OPLL). The proposed OPLL‐based concept can make full‐capacity WT spontaneously respond to frequency events in grid with no more need for frequency measurement and calculations of its variation or differential, which are usually required to calculate the desired extra support power or chosen to trigger a predetermined active power shape etc., in common methods. Comprehensive analysis and comparisons are presented for full‐capacity WT with two different generic control structures by establishing corresponding motion equations with regard to the active current dynamics. The established motion equations theoretically indicate that PLL dynamics and the related active power controls are in the equally important positions and greatly influence the frequency response behaviours of full‐capacity WT, which constitutes the theoretical basis of the proposed OPLL‐based methodologies. Simulated results demonstrate the feasibility and correctness of the OPLL‐based methodologies. The influences of key parameters concerned corresponding to each proposed OPLL‐based methodology are studied. Finally, the proposed methodologies for two generic control structures are also briefly compared and evaluated.

Active distribution networks characterized by high flexibility and controllability are an important development mode of future smart grids to be interconnected with large scale distributed generation sources including intermittent energies. However, the uncertainty of intermittent energy and the diversity of controllable devices make the optimal operation of distribution network a challenging issue. In this paper, we propose a stochastic optimal operation strategy for distribution networks with the objective function considering the operation state of the distribution network. Both distributed generations and flexible loads are taken into consideration in our strategy. The uncertainty of the intermittent energy is considered in this paper to obtain an optimized operation and an efficient utilization of intermittent energy under the worst scenario. Then, Benders decomposition is used in this paper to solve the two-stage max-min problem for stochastic optimal operation. Finally, we test the effectiveness of our strategy under different scenarios of the demonstration project of active distribution network located in Guizhou, China.

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