PV Inverters module strings [RE-wrenches] [RE-wren

Fri Mar 30 18:48:04 PST 2001

One reason why only hundreds, and not thousands or tens of thousands, of
inverters are installed is because of bottlenecks in the distribution system.
Make it easier for new designers, installers, salespeople and customers to
understand and want to sell, buy and install your products. Partner up with
module manufacturers and get them to spec your inverters.

mmangelsdorf at hei.com wrote:

> In my humble opinion, Kent is right.  These types of in-the-field design
> questions are best researched and answered by system designers and
> integrators.  As he notes below, there are too many specific design criteria
> which are site specific and unique to each particular application.
>
> marco
> proVision technologies, inc.
> Hilo, Hawaii
>
> Joel, Honestly this is something that I have not been requested to do
> before. We have many hundreds of PV inverters installed throughout the
> world, and have always relied on the system integrator to decide which
> PV panel and the array configuration would best suit their needs. When
> considering a 600Voc array, there are many considerations that one must
> take that beyond my ability to make a general recomendation statement.
> Take for instance the need to severly derate the open circuit voltage
> due to extreme low temperature, high altitude, or locations which
> typically exhibit irradiances much greater than 1000W/m2. Similarly,
> one may need to add extra panels for high ambient temperatures, poor
> array placement, consistently low irradiance, etc. I could put together
> a table of recommended arrays for standard conditions, which I feel
> would be about as useless as the peak power point voltage as stated by
> the PV manufacturer. The manufactuers PPPVdc does provide a starting
> point when considering all the previously mentioned performance
> effects. A list of recommendations from me would also just be a
> starting point, which could not be used unless all of the other affects
> are considered. And it would open me up to liablity, if someone took
> the recommendation as law, and did no further analysis. This issue may
> be different when considering a low voltage array (24-48Vdc) where only
> one, two or three panels may be required to keep within a relatively
> small DC input window.
>
> If it is the general opinion that a list would be useful, please let me
> know. Again, we recommend any PV panel which will provide a 330-600Vdc
> peak power point voltage.
>
> Regards
>
> -----Original Message-----
> From: Joel Davidson <joeldavidson at earthlink.net>
> Date: Thu, 29 Mar 2001 18:56:32 -0800
> Subject: Re: PV  Inverters module strings [RE-wrenches]
>
> > Kent - We understand that you can not endorse specific solar modules,
> > but (like
> > mount manufacturers) you can make a list of modules that work with
> > your
> > inverters and the number of modules in series. You can caveat the
> > list however
> > you feel necessary. Here's a start with the first 2 modules from this
> > on-going
> > discussion.
> > Siemens SR100 - 24 modules
> > BP Solar BP2150 - 12 modules
> > Siemens SP75 - ? modules
> > BP Solar BP-585UL - ? modules
> > ASE Americas ASE-300 - ? modules
> > Astropower AP-120 - ? modules
> > Astropower APX-75 - ? modules
> > Kyocera KC120-1 - ? modules
> > Photowatt PW1000-95 - ? modules
> > Energy Photovoltaics EPV-40 - ? modules
> > Solarex MST-43 - ? modules
> > Solarex MSX-120 - ? modules
> > United Solar SSR-128 - ? modules
> > United Solar US-64 - ? modules
> > Other modules ?
> >
> >
> >
> > Kent Sheldon wrote:
> >
> > > William, yes I work for the former Trace Technologies, now called
> > Xantrex
> > > Distributed Industrial and Utility Markets Business Unit. I am the
> > POC for
> > > applications questions on the PV series inverter line.
> > Unfortunately, being
> > > that we manufacture inverters, we do not specify specific PV
> > panels, or
> > > arrangements to use with our inverters. This is the job of the
> > system
> > > integrator. What we have done is to specify an allowable voltage
> > operating
> > > window for the inverter. The type or design of the PV module is not
> > > important, as long as the input voltage constraints are met. You
> > must decide
> > > what configuration of PV works best for your application,
> > orientation,
> > > regional location, code requirements, etc. The calculations are
> > rather
> > > straightforward, but require much information specific to the site
> > > installation. I believe Bill Brooks walked you through a possible
> > solution,
> > > which may or may not be adequate for your application.
> > >
> > > Regards,
> > >
> > > Kent Sheldon
> > > Product Manager - Photovoltaic Engineering Group
> > > Xantrex/Trace Technologies Inc.
> > > 925 245 5463/925 245 1022 Fax
> > > kentsheldon at tracetec.com  www.xantrex.com
> > >
> > > -----Original Message-----
> > > From: William Miller [mailto:wrmiller at slonet.org]
> > > Sent: Thursday, March 29, 2001 12:28 PM
> > > To: kentsheldon at tracetec.com
> > > Cc: RE-wrenches at topica.com
> > > Subject: RE: PV Inverters module strings [RE-wrenches]
> > >
> > > Kent:
> > >
> > > Thanks for your reply.  I understand you work for Trace
> > Technologies, the
> > > designer and builder of the PV series inverters.  If you don't have
> > > specific application knowledge, is there someone in your company
> > who does?
> > >
> > > I need to know how many SR100 panels to use with a PV5 and a PV10
> > for a
> > > given climate.  Please correct me if this is not an appropriate
> > question to
> > > ask of a manufacturer.
> > >
> > > I would assume this type of question is fundamental to the support
> > of a
> > > product you manufacture and I would be disappointed if Trace
> > Technology
> > > could not give me very precise data to allow me to purchase and use
> > a
> > > product in their line.
> > >
> > > Thanks,
> > >
> > > William Miller
> > >
> > > At 11:57 AM 3/28/01 -0800, you wrote:
> > > >William, sorry to take so long to get back to you. I am inundated
> > right
> > > now.
> > > >Unfortunately, I rarely get involved in the PV array sizing
> > calculations.
> > > >The only advice I can give you is to make sure the peak power
> > voltage stays
> > > >between 330 to 600. NEC drives most of the voltage window
> > constraints,
> > > >however the manufacturer temperature deratings for the specific PV
> > model
> > > >will also impact the calculations. A side note, the inverter will
> > not power
> > > >track below the minimum allowable DC level. So if your PPTV is
> > lower than
> > > >minimum, the power tracker will back off and continue power
> > production at a
> > > >less efficient point on your array curve. Right now the minimum DC
> > > operating
> > > >voltage is around 328. We are putting some new software through UL
> > which
> > > >will allow the minimum bus voltage to be a function of the AC line
> > voltage,
> > > >allowing for operation below 300Vdc. It will be a few months
> > before this is
> > > >available.
> > > >
> > > >Please contact me if you have any further questions.
> > > >
> > > >Kent Sheldon
> > > >Product Manager - Photovoltaic Engineering Group
> > > >Xantrex/Trace Technologies Inc.
> > > >925 245 5463/925 245 1022 Fax
> > > >kentsheldon at tracetec.com  www.xantrex.com
> > > >
> > >
> > > __________________________________________________________________
> > > William Miller
> > > SLO Communications: Communications and Power Systems Consulting
> > > PO Box 50, Santa Margarita, CA 93453
> > > Voice :805-438-5600             Fax: 805-438-4607       VMail:
> > 805-546-4875
> > > email: wrmiller at slonet.org
> > > License No. C-10-773985
> > > _____________________________________________________________
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> > > CAD: Microstation 95, DXF, Visio 4.1T
> > > _____________________________________________________________
> > > "I stand by all the misstatements that I've made." Dan Quayle
> > > __________________________________________________________________
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