WPP (or subunit) may include the following parts:

• Wind Turbines (WT) including foundations that are in the range of 3-7 MW.

Dependent on location, the next generation of wind turbines will be in the

range on 6-10 MW (primarily offshore). Independent of supplier, WTs will

have power converters in the range of 30-100 %. The WT units are able to

work autonomously or operated by superior control-levels.

• Internal transmission networks are still based on AC but may also be

based on DC in short future. The WTs are normally connected in parallel

along the cable sections as radials. This may vary strongly upon design

and optimizations criteria’s. The communication lines are normally

internally connected along the power cables with integrated fiber cables.

• Substations (transformer- or converter-stations) raise the internal voltage

from medium voltage e.g. 22 kV or 33 kV to high voltage 130 kV or higher

(AC or DC) dependent on the capacity of transmission cable. The

converter substation enables high controllability and simpler means for

disconnecting as well as being autonomous. For redundancy reason, it is

appropriate with 2-3 such units in parallel permitting the WPP to produce

at partly capacity in case of failure.

• External transmission network; Large WPPs are today connected directly

to onshore at 100-150 kVAC, but may also be connected to a multi-drop

HVDC (high voltage direct current) transmission system in the range of

multiples of 100kVDC or interconnecting several onshore regions or

nations.

• Distributed Automation includes the information system within a WPP that

interconnects each individual wind turbine control system to the main

plant control (or via sub plant control if using sub WPPs). The plant control

of the WPP internally manages and operates all the wind turbines and

externally acts as one power generation unit. The main plant controller act

as an interface in-between an external system control operated by a TSO

(transmission system operator) and all individual wind turbines operated

by the GSO (generation system operator).

• Point of common coupling (PCC); is the connecting point where the

electricity produced is supplied to the public electricity supply grid (or

future offshore power system). The location of the PCC can vary

depending on owner responsibilities and grid requirements. The PCC is

normally considered as the interface between the power plant and the grid

where the requirements apply and are validated. The requirements are

related to grid codes and ancillary services.

The internal WPP structure will vary over time depending on economic

optimisation based on availability and controllability constrains as a

consequent from grid requirements. This will also have a continuous effect on

the technology development for years to come.

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I would refer you to my publication on my profile. It has the deep overview of the answers you seek.

Thanks.

Horizontal axis wind turbines are large capacity(more efficient than Vertical axis)   

Here nacelles is placed at the top of the tower and it has much lower cyclic stress now days 95% of the wind turbines are horizontal axis wind turbines. Here yaw mechanism is also required