[RE-wrenches] "Keep that there PV off my grid!"

[Bill Brooks]

Karl,

 

What you are referring to is a "reverse power relay." These are common
devices used for customer-generators. Basler is one company that makes them.
Just google the topic and you will find several companies. The utility may
have a preferred product so go with them if they have one. 

 

There are a few PV installations with these devices. It simply sends a
signal to trip a relay at the inverter if reverse power is ever measured at
the service entrance. It sounds like it is unlikely the device will get much
use except on very special occasions when there servers are offline.

 

Bill.

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Karl Jaeger
Sent: Tuesday, February 15, 2011 3:41 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] "Keep that there PV off my grid!"

 

Dana,

 

This is an instant excess situation, not one electron.

 

I am not sure if this violates federal regulations, but you make a valid
point. I will have to look into it.

 

Honestly, there is a very small probability that any PV will ever make it to
the grid. The service is 1000 Amps and the building has multiple servers
running continuously, all day every day. I am hoping to forego the dumpload
option and the added costs. Word is, they will begin discussions in the
coming months addressing this issue. In the case that they decide to allow
it, it would be an easy fix to remove the contactor and splice the
conductors. 

 

I have heard rumors that a contactor like I described does in fact exist.
But that was some years ago and I cannot remember the details.

 

Thanks,

 

Karl Jaeger

Operations Manager

LightWave Solar Electric

www.lightwavesolar.com

 

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Dana
Sent: Tuesday, February 15, 2011 4:31 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] "Keep that there PV off my grid!"

 

Karl - 

 

Is this instant excess or excess during a specific billing period?

Does this violate Federal regulations?

Could you divert or bank the excess in process heat, water pumping, or some
other function?

 

Dana Orzel

Great Solar Works, Inc

E -  <mailto:dana at solarwork.com> dana at solarwork.com

V - 970.626.5253

F - 970.626.4140

C - 970.209.4076

web -  <http://www.solarwork.com> www.solarwork.com

 

"Responsible Technologies for Responsible People since 1988"

Do not ever believe anything, but seriously trust through action.

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Karl Jaeger
Sent: Tuesday, February 15, 2011 3:21 PM
To: re-wrenches at lists.re-wrenches.org
Subject: [RE-wrenches] "Keep that there PV off my grid!"

 

Greetings Esteemed Wrenches,

 

My company was recently tasked to engineer a PV project in Alabama. We sat
down for a meeting with all of the local big-shots. They proceeded to let us
know that we are not allowed to feed any excess PV power onto their grid,
production cannot exceed demand. I am hoping that y'all might be able to
steer me towards a contactor assembly or device that would detect reverse
current flow, trigger the contactor, then open up the inverter AC output
circuit. The service is 3-phase, 208 volt. The maximum current we intend to
introduce is 70 amps, continuous.

 

Appreciate your advice,

 

Karl Jaeger

Operations Manager

LightWave Solar Electric

www.lightwavesolar.com

 

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