Photovoltaic Diagram Needed

[metallica5]

Have a municipal customer looking for a turnkey 75-85kw photovoltaic system to supplement their Department of Public Works building. They do not have time to go out to have this designed due to grant deadlines. They are looking to us to come up with a game plan to install panels on the ground a few hundred feet from their building. Next is to connect with grid tie to their 3 phase 480 gear. Does anyone know a site online that has diagrams and systems to purchase for installation? Any suggestions from someone experienced in this?

 

[iwire]

I have done a few systems and the company has done a bunch.

It is my opinion that you should hire someone that knows what they are doing. You generally cannot get the grants unless the system passes a number of inspections from different people (in this area often engineers with very little tolerance for deviations) and unless you have done these before you are damn likely to make a bunch of mistakes.

For instance the lugs used for grounding the panels better be listed for wet locations, in other words you will need direct burial lugs at about $4.00 each.

You need to know how to size the conductors based on the short circuit value if the modules in the circuit and add 125% twice, along with ambient temp adjustments.

Now that said, here are some great links that may help you.

College of Engineering Southwest Technology Development Institute

College of Engineering Southwest Technology Development Institute Codes & Standards

Photovoltaic Power Systems and the National Electrical Code: Suggested Practices

The North American Board of Certified Energy Practitioners (NABCEP)

 

[ggunn]

Have a municipal customer looking for a turnkey 75-85kw photovoltaic system to supplement their Department of Public Works building. They do not have time to go out to have this designed due to grant deadlines. They are looking to us to come up with a game plan to install panels on the ground a few hundred feet from their building. Next is to connect with grid tie to their 3 phase 480 gear. Does anyone know a site online that has diagrams and systems to purchase for installation? Any suggestions from someone experienced in this?

I will echo what iwire said. There's a lot to take into consideration, and every system is different. You have to match modules and module circuit configurations to the inverter of choice, and climate conditions play a role in the design. A 85kW system is a fairly sizeable one; you'll want to have someone experienced at designing PV systems to work up the design. It's not exactly rocket science, but you can't just throw out a generic plan and expect it to work.

That said, someone with experience at this sort of thing could probably gen up a basic electrical design for a system like this in a couple of hours.

 

[metallica5]

Understood. Customer just wants to have something to submit to land the grant to go through with the project. My thought was to put something together for them to submit. Once grant was obtained then we would get a design engineer in to do proper design of a whole system. I will check the links that iwire mentioned.

 

[BillK-AZ]

You need to pay a lot of attention to the point of connection, Art 690.64, especially if the service is 1000A or higher with ground fault protection. Most main breakers (if so equipped) for this are not listed for backfeed (this is not part of the UL test series for these breakers) and most packaged service entrances do not have a provision for supply side connections.