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With increasing renewable distributed energy resources integrated into a microgrid, it is difficult to realize its optimal operation due to uncertain power outputs of wind turbines, photovoltaic cells, etc. This paper presents a flexible scheduling model for microgrid optimal operation, in which both the expectation of operational cost and the robustness of scheduling solutions are taken into account...
The characterization of near-field couplings becomes an extremely important activity to optimize the best nominal performance of any electronic device in the presence of others. In order to handle the electromagnetic compatibility (EMC) problems at the initial design phase, a predictive method based on multipolar expansion in spherical harmonics has been developed. A new automatic measurement system...
In the Joule Balance at the National Institute of Metrology (NIM), the dynamic measurement during the coil movement is avoided. But for this method a rather large current in the primary coil is needed to generate the necessary magnetic field in the force weighing phase. Thus the coil heating becomes an obvious uncertainty contribution. To solve this problem, a new coil system, in which the ferromagnetic...
The Joule balance method to measure the Planck constant and redefine the Kilogram ultimately has been going on at the National Institute of Metrology of China (NIM) since 2007. The first prototype has been built to check the feasibility of the principle. In 2012, the relative uncertainty of the plank constant measurement result is at 10−5 level. Self-heating of the coils, swing of the coil, etc.,...
Based on the special structure of exciting coils system of joule balance, the uncertainty sources of the magnetic density in the geometrical center of magnetic field was analyzed and evaluated. The relative combined standard uncertainty of magnetic field in ΔH/H was 4.9 × 10−4. In addition, it was proved that the largest component of uncertainty was u(I), which was 2.8×10−4. Therefore the high-precision...
The Joule Balance method, for the same purpose but different from the Watt Balance method, is going on at NIM for several years. The first measurement result of the Planck constant h is 6.6261(5)×10−34Js with a measurement uncertainty of 7.7 × 10−5. The further plan for improvement is discussed.
In the weighing phase of the Joule Balance, to get a high enough magnetic field and avoid the heating from the coil wound with normal enameled copper wire, a superconducting magnet is used as the fixed coil. The mutual inductance measurement between this superconducting coil and the movable coil of enamel copper wire should be measured precisely. A standard square-wave compensation method has been...
Traditionally, the most precise way to get the mutual inductance value is by a calculable mutual inductor. Here a new approach of measuring the mutual inductance at low frequency with compensation method is described. The mutual inductance is traced to the value of the frequency and resistance directly. The measurement uncertainty is 0.1 ppm and could be improved further.
This paper presents a formulation of fuzzy mixed integer programming (FMIP) solution for solving security-constrained unit commitment (SCUC) problem with emphasis on uncertainties in forecasted parameters in constraints. The proposed approach could be used by vertically integrated utilities as well as the ISOs in restructured power system. In this model, uncertainties in forecasted load demand, ancillary...
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