After providing a better service for nearby heating loads, a thermal storage electric boiler system can use the heat storage tank to participate in the peak-shaving and reserve services of the power grid. Current researches focus on its peak-shaving capacity, but ignores the use of its reserve capacity, which is important to the random fluctuations of renewable energy sources. Facing the actual analyzing demands on power system adequacy, this paper starts with the discussion of typical operation modes, and builds the powersystem- adequacy model of a thermal-storage electric boiler based heating system. Based on the presented model, the concept of feasible domain for heat charging and discharging is proposed. By implementing the concept, the quantitative evaluation method to calculate the reserve capacity of a thermal storage electric boiler system is proposed. The verification of the method is also given. Based on the planning data of an actual power grid, the short-term reserve capacity as well as the effect on promoting renewable energy consumption is estimated according to the given size of the provincial thermal storage electric boiler clusters. Finally, the influences of different choices of peak-shaving strategies, heat storage tank capacity on its reserve capacity are simulated and analyzed.

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In this paper, a new method using wind turbulence excitation is proposed to estimate the parameters of the mechanical system (drivetrain and pitch angle controller) in a Doubly Fed Induction Generator (DFIG) Wind Turbine (WT). Firstly, simulations were carried out for a DFIG WT under turbulence excitations. The spectral contents of the responses imply that the transients of the electrical system (generator and converter), which are much faster than those of the mechanical system, can be neglected when estimating the mechanical parameters. Based on this, a simplified model related to the mechanical system of the DFIG WT was derived by applying the model reduction technique. Secondly, the parameter sensitivity of Power Spectral Density (PSD) was used to quantify the impacts of individual parameters on the dynamics of the mechanical system, and the influential parameters were selected on the basis of the sensitivity results. Finally, a weighted least-squares optimization problem, which is suitable for a system with close oscillation modes, was formulated for parameter estimation. The estimation results based on two different types of optimization methods were compared, and their estimation accuracies validate the effectiveness of the proposed method.

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