By means of small wind turbines, it is possible to create distributed sources of electricity useful in areas with good wind conditions. Sometimes, however, it is possible to use small wind turbines also in areas characterized by lower average wind speeds during the year. At the small wind turbine design stage, various types of technical solutions to increase the speed of the wind stream, as well as to optimally orientate it, can be applied. The methods for increasing the efficiency of wind energy conversion into electricity in the case of a wind turbine include: the use of a diffuser shielding the turbine rotor and the optimization of blades mounted on the turbine rotor. In the paper, the influence of the diffuser and rotor blades geometry on the efficiency of an exemplary wind turbine for exploitation in the West Pomeranian Province is investigated. The analyses are performed for three types of the diffuser and for three types of rotor blades. Based on them, the most optimal shapes of the diffuser and blades are selected due to the efficiency of the wind turbine. For the turbine with the designed diffuser, calculations of the output power for the assumed different values of the average annual wind speed and the constant Betz power factor and the specified generator efficiency are made. In all the analyzed cases, the amount of energy that can be generated by the turbine during the year is also estimated. Important practical conclusions are formulated on the basis of these calculations. In the final part of the paper, a 3D model of the wind turbine with the diffuser and rotor blades chosen based on earlier analyses is presented. As a material for the diffuser and rotor blades, glass fiber type A is applied. By means of calculations using the finite element method, the limit displacement of the turbine structure under the influence of a hurricane wind are determined. Based on these calculations, the correctness of the modelled small wind turbine structure has been demonstrated.
Paper presents the concept of energy storage system based on power-to-gas-to-power (P2G2P) technology. The system consists of a gas turbine co-ﬁring hydrogen, which is supplied from a distributed electrolysis installations, powered by the wind farms located a short distance from the potential construction site of the gas turbine. In the paper the location of this type of investment was selected. As part of the analyses, the area of wind farms covered by the storage system and the share of the electricity production which is subjected storage has been changed. The dependence of the changed quantities on the potential of the hydrogen production and the operating time of the gas turbine was analyzed. Additionally, preliminary economic analyses of the proposed energy storage system were carried out.
The aim of the investigation presented in this work was to realise complex calculations of a new, combined water-steam system with peak-load hydrogen turbine to be applied in nuclear units with gas-cooled reactors. The system’s characteristic feature is the presence of two heat sources: a nuclear steam generator; and a hydrogen-oxygen combustion chamber. The main idea is to create a system capable to operate in two modes, with one or two heat sources, which leads to a significant output change. The investigation included also the overall efficiency of conversion of the nuclear energy, assumed the heat needed for producing hydrogen and oxygen comes from such a source. This part of the work included an analysis of the rationality of hydrogen production and utilisation. An additional aim of the research was to determine the optimal solution regarding the system performance and the capability of its technical realisation. The obtained results are promising: the system performance is very high, and its operating parameters are technically realisable in today’s conditions. In addition, it enables an emission-free, dispatchable electricity generation during the daytime demand peak.
In this paper a system of a grid side and a generator side converters, both working with a common capacitor, is presented. The 6-phase asymmetric inset-type SMPMSM generator is used. A large pole pair number of this generator enables a gearless wind turbine operation. The fundamental and 3rd harmonic cooperation is used to increase the generator performance. This is accomplished by means of the 3rd harmonic current injection. For that reason the generator side converter must have a neutral connection.
In renewable systems, there may be conditions that can be either network error or power transmission line and environmental conditions such as when the wind speed is unbalanced and the wind turbine is connected to the grid. In this case, the control system is not damaged and will remain stable in the power transmission system. Voltage stability studies on an independent wind turbine at fault time and after fixing the error is one of the topics that can strengthen the future of independent collections. At the time of the fault, the network current increases dramatically, resulting in a higher voltage drop. Hence the talk of fast voltage recovery during error and after fixing the error and protection of rotor and grid side converters against the fault current and also protection against rising DC voltage (which sharply increases during error) is highly regarded. So, several improvements have been made to the construction of a doubly-fed induction generator (DFIG) turbine such as: a) error detection system, b) DC link protection, c) crow bar circuit, d) block of the rotor and stator side converters, e) injecting reactive power during error, f) nonlinear control design for turbine blades, g) tuning and harmonization of controllers used to keep up the power quality and to stabilize the system output voltage in the power grid. First, the dynamic models of a wind turbine, gearbox, and DFIG are presented. Then the controllers are modeled. The results of the simulation have been validated in MATLAB/Simulink.
To study the principle of loss and heat at the end region of large 4-poles nuclear power turbine generator, 3D transient electromagnetic field and 3D steady temperature field finite element (FE) models of the end region are established respectively. Considering the factors such as rotor motion, core non-linearity and time-varying of electromagnetic field, the anisotropic heat conductivity and different heat dissipation conditions of stator end region, a 50 Hz, 1150 MW, 4-poles nuclear power turbine generator is investigated. The loss and heat at the generator end region are calculated respectively at no-load and rated-load, and the calculation results are compared with the test data. The result shows that the calculation model is accurate and the generator design is suitable. The method is valuable for the research of loss and heat at the end region of large 4-poles nuclear power turbine generator and the improvement of the generator’s operation stability. The method has been applied successfully for the design of the larger nuclear power turbine generators.