In the previous article, the download and installation of the toolbox were mainly introduced. In this article, the use of the toolbox is briefly introduced.
For a more detailed introduction,
Reference 《Aeolus Toolbox for Dynamics Wind Farm Model, Simulation and Control》
5. Example simulation
In the decompressed file, there are two files framed above, double click to open one of the files. as follows:
When running this instance, let's first analyze what this example does. In order to facilitate the later use of the toolbox.
In the above model, several large modules are included: wind turbine, wind farm controller, wind farm, network controller, grid model and network load model.
Because the toolbox is mainly for the simulation of wind farms, some element events will be restricted and simplified:
1) Constant average wind speed
During the simulation process of the whole wind farm, the average wind speed of the wind speed is always constant.
2) Constant mean wind direction
The wind direction is constant relative to a well-designed wind farm. If you want to change the wind direction, you can rearrange the wind farm (relative position, the wind direction remains the same, and the position of the wind turbine changes.)
3) Two-dimensional wind field
The wind field is only generated at the height of the hub, and the wind shear and tower shadow effects are not considered at present.
4) No yaw system
There is no yaw system, that is, the angle of the wind turbine relative to the wind cannot be changed, that is, the wind direction is considered to be constant.
1. What should we pay attention to when building a model of a wind farm
1) We know that wind is a random source of energy, we must be able to simulate the flow of wind farms.
For example, if there is a row of fans on the windward side, after the wind flows through the exhaust fans, it will definitely affect the fans in the next row.
2) The model also includes the main aerodynamic influences that allow the controller to manage these flowing resources within the wind farm.
For example, the optimal power and load effects can be optimized when constructing the objective function.
2. Wind farm design
In the above introduction, we know that the wind farm of this model is a two-dimensional wind farm, and we can arrange the position of the wind turbine by ourselves.
Wind speed and wind direction are the main sources of wind farm input, so they should be given when designing the wind farm. In the picture above, we can design the position of the fan and modify the size of the grid.
3. Wind turbines
Click on the lower triangle position of the module to see the detailed internal model.
The fan is a 5 megawatt fan. It can be seen that there are multiple outputs of the fan, but three are necessary (because it is based on load)
1) P[W] The power output generated by the wind turbine
2) Thrust coefficient of CT tower
3) The wind speed in the nacelle measured by v_nac
The rest of the output is used as some auxiliary output, which is not used in the model, but for the convenience of discussing other issues. Brief description here:
4) w_gen generator speed
5) Sensor measurement of pitch pitch angle
6) Torque of M_shaft rotor shaft
7) Bending moment of M_tow tower
8) Aux user-defined output
Three input parameters:
1) P_max is the power reference from the controller
2) v_rot effective wind speed, average rotor wind speed
3) v_nac is the wind speed at the nacelle grid point
The picture above shows the relevant parameters of the wind turbine, including wind speed, rotation, and some information of the wind turbine.
The above is the structural diagram of the wind turbine when it was built.
Open the fan module, you can see that each module is the corresponding structure. To see the corresponding formula derivation, see the recommended reference papers.
4. Wind Field Modeling
The wind field can be described as two models, one is the natural wind field without the fan, and the other is the wind field affected by the wake of the fan. And both models assume that Taylor's inviscid freezing hypothesis is true. The following two wind field models are introduced in detail:
4.1 Natural wind field
The wind speed at different points of the model is constructed by the spectral matrix method, and the average wind speed is constant, that is, the longitudinal average wind speed is constant.
According to the frozen turbulence hypothesis, we can randomly generate the wind speed of the rear fans only by setting the wind speed of the first horizontal row.
4.2 Wake wind field
The part of the wake will not be elaborated here.
5. Wind farm controller
The allocation of power is controlled according to the proportional allocation.
6. Summarize
Adjust the "light bulb", that is, the load of the user on the grid side, and the change of the load will cause the change of the frequency. The current power generated by the wind farm and the load power can be known in the grid measurement, and the change of the grid frequency can be obtained. On the grid controller, the frequency of the grid at the time of input and the estimated available power from the wind farm. After calculation, the reference power is transmitted to the wind farm controller. The wind farm controller is distributed proportionally, and the power is distributed to each wind turbine. The simulated wind field is used to calculate the output power of the wind turbine and the load of the tower.
You can add an oscilloscope to see the power curve and other information, or you can click on the signs similar to the wifi symbol to view the curve information.