20kW wind turbines, UK grid connection?

[energytech]

We are having alot of interest in 10-30kW wind turbines lately. We would usually advise to go larger as this makes more economical sense with payback times etc. However, it is often the case that the larger turbines are to large for planning, initial cost etc. The range of good value Navirton turbines has changed the way we think and we want to offer these medium size turbines to our customers.

We would like to know if anyone has sucessfully connected a 10kW or 20kW Navitron turbine to the grid? Are these turbines suitable for grid connection in the UK? What are the necessary electronics to make this possible and where are these available from?

We under stand that the local electricity supplier would need to perform a 'Grid Connevtion Survey' for machines of this size, but what we are interested in is if the electronics are available to connevt to the grid if the survey has a positive outcome.

Cheers,  Olly

[Alan]

The short version.
Easy and cheap to do.  To satisfy legal requirements, not as straight forward.

The long version

To include protection devices in the inverter that disconnect the voltage before 600 Volts D.C. is reached and use this energy in a controlled manner is very straight forward to achieve.
Using a simple Microchip processor with the required software to derive Pulse width modulation driving IGBT fets to control / disconnect the D.C. bus voltage during synchronisation and while exporting. If built inside the inverter the existing snubbing and high frequency filtering components that are all ready required to achieve Electro Magnetic computability are already fitted. To be fail safe the inverter would also require an additional contactor to disconnect the D.C. supply in the event of electronics failure. Additional cost would be very minimal.

To build an external device  Again very straight forward. To get it tested fail safe and pass the relevant testing for C.E. marking and E.M.C. requirements would be a very costly procedure.

Device works well and allows energy to be utilised in lower wind speeds. Excess energy is used for immersion heater and additional under floor heating when the water tank thermostats are satisfied.

( Electro Magnetic Computability )  means the device will not cause other electronic equipment to malfunction, will not emit radio waves on any frequency capable of causing interference to other users. Will not be influenced by radio waves from other devices causing it to malfunction.

THE HEALTH WARNING. Unless your Skill level allows you to safely work on
LIVE MAINS    voltage equipment with complete confidence. You should not be getting involved with high voltage direct current stored energy devices.
Do not use conventional thermo stats to control D.C. voltage.

Regards

Alan.

[Alan]

Cant spell Should say   Compatability.

[Ivan]

Unfortunately, the only real option at the moment is to do what everyone else is doing and use the SMA grid-connect equipment 'windy boy' - this is rather overpriced, but the lack of competitors and the high demand means it is likely to stay that way. We have some detail of the 2kW turbine grid-connected, but our site is not ideal for testing these things. We are hoping to set up a new demo-site in Leicester in September, and if all goes well, we should have all the wind turbines on display there including the larger ones grid-connected.


Ivan

[scottishhardwood]

Hi
I have a 10Kw Chinese turbine connected to grid with 2 windyboy 6000's.
I had to build my own safety circuit, I start to switch in dump loads across turbine output as the voltage rises towards 600v, and disconnects the inverter from the turbine when out reaches 600v. I had to build the switches myself as I found all the igbt and solidstate switches did not fail safe. I went for pneumatic switches that I engineered myself.
The main problem I am having with the Chinese system is that it is supposed to turn out of the wind when the wind gets too strong, but if the wind indicator fails it does not move and this can destroy the turbine and blades.
Does anyone else have one of the 10Kw or 20Kw turbines, and what have they done about the controls?
I am looking at building my own controller with back up sensors etc.