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To avoid possible conflicts between the maintenance scheduling and the unit commitment for hydro-thermal power systems under the traditional non-collaborative optimization mode,a collaborative maintenance scheduling and unit commitment model for hydro-thermal systems is proposed,in which the total cost of the system and the adjustment cost of maintenance scheduling as an objective are minimized with considering the coupling characteristics of cascade hydropower. Furthermore,the model is transformed into a mixed integer linear programming (MILP) model. To improve the solution of the MILP model,the objective scaling ensemble approach is proposed,including two stages. In the first stage,the coefficients of integer variables in the objective are scaled and the integer variables that may take 0 are probed. In the second stage,the reduced MILP model is solved after determining and fixing the integer variables with a value of 0. Finally,a 6-unit hydro-thermal power system and an actual provincial 86-unit hydro-thermal power system are taken as test systems. The results show that the proposed model can obtain a more economical and reasonable maintenance scheduling and unit commitment scheme compared with the non-collaborative optimization mode,thus effectively improving the solution speed by the objective scaling ensemble approach.

[Introduction] Aiming at allocating renewable energy consumption responsibility weight problem among market subjects, an allocation method based on evolutionary game and stochastic optimization is proposed. [Method] First of all, each market subject was taken as a limited rational individual participate in the weakly linked evolutionary game, and the absorption weight undertaking scheme that minimizes its own cost in the evolutionary equilibriumwas obtained and the selection strategy tendency of each market subject under the probability interval of different rewards and punishments adopted by the government was obtained. Then, after getting the probability interval of different reward and punishment measures taken by the government, a stochastic optimization model was used to get the specific scheme of absorbing weight which couldminimize the cost of each subject in each probability interval. [Result] The effectiveness and practicability of the proposed method is verified by calculating the data of 170 market entities in a provincial power grid. [Conclusion] A new method and idea on the weight distribution method of renewable energy absorption responsibility is provided, and feasible suggestions for the government to strengthen the enthusiasm of market subjects in the absorption of renewable energyare put forward in this paper.

Maglev vehicles apply the entire vehicle load uniformly onto bridges through levitation forces. In assessing the dynamic characteristics of the maglev train–bridge coupling system, it is reasonable to simplify the distributed levitation force as a concentrated force. This article theoretically derives the analytical response of bridge dynamics under the action of a single constant force and conducts numerical simulations for a moving single constant force and a series of equally spaced constant forces passing over simply supported beams and two-span continuous beams, respectively. The topic of discussion is the response of bridge dynamics when different degrees of force concentration are involved. High-precision displacement and acceleration sensors were utilized to conduct tests on the Shanghai maglev line to verify the accuracy of the simulation results. The results indicate that when simplifying the distributed levitation force into a concentrated force model, a frequency ratio can be used to analyze the conditions for resonance between the train and the bridge and to calculate the critical speed of the train; the levitation distribution force of a high-speed maglev vehicle can be simplified into four groups of concentrated forces based on the number of levitation frames to achieve sufficient accuracy, with the dynamic response of the bridge being close to that under distributed loads. [ABSTRACT FROM AUTHOR]

[Introduction] Based on the trend of consuming renewable energy sources (RES) through the market-based trading model, the “market electricity price + renewable energy certificate (REC) revenue” will become the main operation of energy generators in the future. Based on the research background of RES participating in spot power market, this paper studies the price of REC. [Method] Based on the optimized clearing model of the spot electric energy market, applying the theory of the life cycle costing (LCC) of RES generation and satisfying the internal rate of return (IRR) of the energy generators, we established the optimization model of coupling REC-electric energy market. Combined with the seasonal output characteristics of RES, the simulation and measurement methods of the seasonal curve and fluctuation interval of REC price are proposed. [Result] The price of REC for different types of RES are different, and the price of REC for different types of RES also has different climatic correlations. [Conclusion] Scientific and reasonable calculation of REC price can not only help RES generation enterprises make income assessment and more accurate investment decisions, but also provide relevant decision-making support for power market entities and trading centers.

As the amount of distributed energy storage (DES) in a power system continues to increase, it will not be long before there are multiple DES aggregators participating in frequency regulation, and the realization of their coordinated control is a critical topic of current research. This study focused on the primary frequency regulation (PFR) power allocation strategy among multiple DES aggregators participating in PFR. This study first calculated the PFR demand according to a system frequency response model of the power system with DESs. Next, a PFR power allocation model of DES aggregators was developed based on model predictive control. The objective of this model was to minimize the overall frequency regulation cost while satisfying all of the constraints of DESs. Finally, the distributed interior point method was used to solve the model rapidly. The correctness and effectiveness of the proposed model and algorithm were verified on two unified transmission and distribution systems with DES aggregators used to supply the PFR service. The results revealed that the proposed model could effectively allocate PFR power to the various types of energy storage, with the additional benefits of slowing down the shift in the state of charge for energy storage units and ensuring the continuity of energy storage participation in frequency regulation. [ABSTRACT FROM AUTHOR]