Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor having one or more rotor blades. The rotor blades transform wind energy into a mechanical rotational torque that drives one or more generators via the rotor. The generators are sometimes, but not always, rotationally coupled to the rotor through the gearbox. The gearbox steps up the inherently low rotational speed of the rotor for the generator to efficiently convert the rotational mechanical energy to electrical energy, which is fed into a utility grid via at least one electrical connection. Such configurations may also include power converters that are used to convert a frequency of generated electric power to a frequency substantially similar to a utility grid frequency.
A plurality of wind turbines are commonly used in conjunction with one another to generate electricity and are commonly referred to as a “wind farm.” Wind turbines on a wind farm typically include their own meteorological monitors that perform, for example, temperature, wind speed, wind direction, barometric pressure, and/or air density measurements. In addition, a separate meteorological mast or tower (“met mast”) having higher quality meteorological instruments that can provide more accurate measurements at one point in the farm is commonly provided. The correlation of meteorological data with power output allows the empirical determination of a “power curve” for the individual wind turbines.
Traditionally, wind farms are controlled in a decentralized fashion to generate power such that each turbine is operated to maximize local energy output and to minimize impacts of local fatigue and extreme loads. To this end, each turbine includes a control module, which attempts to maximize power output of the turbine in the face of varying wind and grid conditions, while satisfying constraints like sub-system ratings and component loads. Based on the determined maximum power output, the control module controls the operation of various turbine components, such as the generator/power converter, the pitch system, the brakes, and the yaw mechanism to reach the maximum power efficiency.
However, in practice, such independent optimization of the wind turbines ignores farm-level performance goals, thereby leading to sub-optimal performance at the wind farm level. For example, downwind turbines may experience large wake effects caused by one or more upwind or upstream turbines. Because of such wake effects, downwind turbines receive wind at a lower speed, drastically affecting their power output (as power output increases with wind speed). Consequently, maximum efficiency of a few wind turbines may lead to sub-optimal power output, performance, or longevity of other wind turbines in the wind farm.
In addition, there are many products, features, and/or upgrades available for wind turbines and/or wind farms configured to minimize wake effects and/or increase power production of the wind farm. Conversely, there are upgrades aimed at increasing single-turbine performance that may unintentionally have adverse impacts on overall wake losses within the wind farm. In either situation, it is advantageous to efficiently verify impact on overall wake losses of the wind farm, however, such verification can be difficult to obtain.
More specifically, when assessing changes in farm-level performance, most existing approaches rely on cumulative farm-level energy production, which is prohibitive in terms of data retention because it may require all turbines to be simultaneously in a valid operating state for a time-stamp to be considered valid (full/partial load operation, no curtailment, etc.). This requirement generally results in a substantial reduction (e.g. 70-80%) in the size of the overall dataset.
Thus, a system and method for assessing changes in farm-level performance of a wind farm via pairwise cascade maps that addresses the aforementioned issues would be advantageous.
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