power quality problems [RE-wrenches]

[Bill Brooks]

Marco,

I sincerely doubt that the power quality problems are a direct result of the
new wind turbines. These new turbines are all inverter-based, variable-speed
units, and do not create the same frequency oscillations that were caused by
the older induction-generator-based units. 

I think the power quality sucks on the big island because so much load has
been added and the system is barely able to keep up with it. Don't blame
renewables for problems caused by mega-air conditioning loads on the Kona
side of the island. You need more PV over there to reduce the load on the
transmission and distribution system. The system can handle way more PV than
it has right now, but the operating parameters of the systems will have to
be adjusted. Because the grid fluctuations are so large in the islands, the
mainland-based operating parameters simply do not apply. We actually wrote
that directly into the IEEE 929 standard because we knew the tight voltage
and frequency limits of IEEE 929 would cause problems in Hawaii--and
amazingly they are.

Bill.

Bill Brooks, PE
Brooks Engineering
873 Kells Circle
Vacaville, CA 95688
office and mobile phone: 707-332-0761
fax:707-451-7739
email: billbrooks7 at yahoo.com
web: www.brooksolar.com

Ecclesiastes 11:7 Light is sweet, and it pleases the eyes to see the sun.


> -----Original Message-----
> From: Marco Mangelsdorf [mailto:marco at pvthawaii.com]
> Sent: Thursday, July 26, 2007 9:53 AM
> To: RE-wrenches at topica.com
> Subject: power quality problems [RE-wrenches]
> 
> 
> We appear to be having power quality issues with our local utility.  I've
> replaced the grid-tie 4 kW inverter twice now and my customer is still
> seeing the bugger trip off-line frequently during the day.  There happens
> to
> be an 11 MW windfarm not more than 10 miles from the site and I know that
> frequency drift is an issue, so I have widened the frequency window of the
> inverter (with the utility's knowledge and approval).
> 
> My question: are there any other things I should be looking for?  Harmonic
> distortion? Gremlins in the transformers?  And can anyone recommend a
> relatively inexpensive data recorder which could sit up at the site for a
> week or so and record events?
> 
> I'm all for wind farms, but am now concerned that our 30+ MWs worth of
> wind-based power (in a grid of ~ 200 MW peak generating capacity) may not
> be
> a good thing for all of my grid-tie systems.
> 
> Thanks,
> marco


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