Talk:Variable speed wind turbine

Background
I'm confused by the first two sentences of this section.

My common sense tells me that fixed speed turbines are beneficial from the moment that you want to connect the turbines to the grid. I can imagine that variable speed turbines have a higher efficiency, as they can adjust the rotor speed to the wind speed.

So as long as there is no requirement to connect to the grid, I guess variable speed turbines would be preferred. From the moment you connect to the grid, you'd want to switch to fixed speed.

Now first sentence goes "Before the need to connect wind turbines to the grid, turbines were fixed-speed". Strange, maybe variable speed was meant here??

Second sentence "This was not a problem because turbines did not have to be synchronized with the frequency of the grid." This would make sense if the first sentence would be regarding variable speed turbines. — Preceding unsigned comment added by 2A02:1810:3886:9A00:11B8:34FA:431E:3AB7 (talk) 12:00, 30 September 2020 (UTC)

Referencing and detail
No referencing given for the last section, and details are thin on some parts. Particularly with the equations, units of calculation should be given, for example the length of the rotor blade - is it in metres or millimetres? And in the second section, is 'N' in rpm or rad/s? - Roobens (talk) 12:28, 10 March 2014 (UTC)

Hi Roobens. For the tip-speed ratio, the units cancel so it doesn't matter. For rotor speeds it's rad/s. Note also I've corrected what R is. It used to say blade length, but that's not accurate because the hub where the blades attach contributes to the rotor radius. And the rotor blades are coned, which reduces the apparent area of the rotor. RatnimSnave (talk) 12:50, 1 July 2019 (UTC)

Introduction
Does it need a preliminary sentence to say that this is specifically about variable speed wind turbines for grid power generation and linking back to https://en.wikipedia.org/wiki/Wind_turbine ? (BTW I am a newbie to Wikipedia and wind turbines, so please forgive my ignorance)

Going straight into a graph is a bit heavy. Would the content from "The aerodynamic efficiency," onwards be better moved to the section "Torque Rotor-speed diagrams"?

What is the source of the Cp/lambda graph? From the context I would have expected it to be a theoretical/modelled curve, but the fact that is it not smooth suggests to me that it is measured from a real system. Is it therefore just a representative sample, in which case it would prevent confusion to describe it as "typical" or "representative".

Is it helpful to show the negative part of the graph? Presumably it implies that power is consumed rather than generated at these speeds, but I suspect this never happens. Rocky Allen 2 (talk) 21:35, 30 October 2020 (UTC)

Torque Rotor-speed diagrams
This currently looks like a subsection of "History". Does it need a new section heading "Theory"? Rocky Allen 2 (talk) 21:38, 30 October 2020 (UTC)

Blade forces
This is currently a new section. Should it be merged with the previous formulas in a new "Theory" section?

Is there an equation missing at the end? (nothing appears on Ubuntu/Chrome) Rocky Allen 2 (talk) 21:42, 30 October 2020 (UTC)

Operating strategies for variable speed wind turbines
At very high wind speeds, I believe they mechanically brake turbines with fixed pitch blades. If so, should it be mentioned for completeness? Do they still do this for variable pitch blades? Rocky Allen 2 (talk) 21:58, 30 October 2020 (UTC)