Source Power Recognition

[metallica5]

I have a 3 phase 480/277 2500 amp main switchboard that is fed from both a 400kw fuel cell and utility power. The fuel cell is to be the main source of power until it reaches it's capacity. Once fuel cell capacity is reached, Utility power will supplement. Utility power comes into main breaker in switchboard while the fuel cell power comes in via an 800 amp branch breaker. While the main board is being fed simultaneously from both sources, what determines that the loads will be served by the fuel cell power first?

 

[iwire]

I have a 3 phase 480/277 2500 amp main switchboard that is fed from both a 400kw fuel cell and utility power. The fuel cell is to be the main source of power until it reaches it's capacity. Once fuel cell capacity is reached, Utility power will supplement. Utility power comes into main breaker in switchboard while the fuel cell power comes in via an 800 amp branch breaker. While the main board is being fed simultaneously from both sources, what determines that the loads will be served by the fuel cell power first?

Is the company UTC?

Anyway the fuel cell determines what it will pick up. I may be mistaken but I believe it does this by adjusting it's output voltage up or down as needed.

I also imagine you have a some extra CTs and PTs in your switch gear connected to a 'Beckworth' device that watches which way the current is flowing in the switch gear.

 

[metallica5]

You are correct (UTC) and there are separate CT/PT's

 

[iwire]

You are correct (UTC) and there are separate CT/PT's

We have done three of their 400 KW units in three locations.

 

[metallica5]

I'm assuming from your response that the fuel cell monitors the utility voltage and adjusts the fuel cell voltage accordingly. For the fuel cell to be the primary source, does it need to raise it's voltage slightly higher?

 

[iwire]

I'm assuming from your response that the fuel cell monitors the utility voltage and adjusts the fuel cell voltage accordingly. For the fuel cell to be the primary source, does it need to raise it's voltage slightly higher?

I believe that is the case but I am not an expert on that end of it.

I am going to be with UTC tonight, if I remember I will ask them about it.

Any chance your contact is Lindsey?

 

[metallica5]

The ultimate owner is a municipality that had the fuel cell installed in between two new schools. The first school was built in 2010 and the installed another electrical contractor. We are contracted to for the second school being built right now. The feed for the new school is coming from the same main switch gear the feeds the school built in 2010. We came in after the fuel cell installation and do not know the UTC rep for the project.

 

[iwire]

I see that member kingpb is around, he could help if he sees this thread.

 

[kingpb]

It will be a function of the load management control system, I assume provided by UTC with the fuel cell or part of the paralleling switchgear, which will control voltage and frequency; to perform as desired.

 

[metallica5]

In some cases being primarily from the installation side of things vs. the engineering side makes it hard to comprehend how some theory works. From what I'm getting is that the load management system (either on the gear or the fuel cell) adjusts the voltage and or frequency to a higher level than the utility so that it is the power consumed first. Once the fuel cell reaches capacity, the management system will sense this and allow the utility source to supplement?

 

[kingpb]

From what I'm getting is that the load management system (either on the gear or the fuel cell) adjusts the voltage and or frequency to a higher level than the utility so that it is the power consumed first.

For the most part that's what it does.

Once the fuel cell reaches capacity, the management system will sense this and allow the utility source to supplement?

The management system will only be measuring the utility source and adjusting the fuel cell accordingly. Once you are at maximum output capacity, the utility will automatically provide the excess, as it is operating in parallel with the fuel cell. The management system has no control capability of the utility source. You just use/take what you can't supply yourself.

 

[bob]

For some time the fuel cell has been talked about as a residental power source. Are the available
in a smaller package? What is the price?

 

[metallica5]

Thanks for the info Kingpb. As far as being used in residential, someone else will have to answer on that as we do not get into installation of fuel cells. This one just happens to be an existing unit that is feeding power to our project. From what I gathered so far, fuel cells are not an economical source of alternative power in the residential or commercial market.