Apparent wind in knots and degrees. Note that a number of additional factors come into play when converting the measurements from the masthead anemometer into the true wind if a high degree of accuracy is required, including the following: In the presence of a current, the true wind is considered to be that measured on the craft drifting with the water over the bottom, and wind with respect to the sea bed as the "ground" or "geographical wind". The apparent wind on board (a boat) is often quoted as a speed measured by a masthead transducer containing an anemometer and wind vane
Tip-speed ratio and then converts that signal to an AC signal with the grid/transmission system frequency. As already mentioned, variable speed wind turbines cannot be directly connected to a transmission system. One of the drawbacks of this is that the inertia of the transmission system is reduced as more variable speed wind turbines are put online. This can result in more significant drops in the transmission system's voltage frequency in the event of the loss of a generating unit. Furthermore, variable speed wind turbines require power electronics, which increases the complexity of the turbine and introduces new sources of failures. It has