Using PC as a microcontroller

[ssembo]

You need to come up with all the parts here .

Power sensing
Phase sensing
Then line switching
Offline power
On line power

Could use a phase detector for phase sensing but what of the power, do i need to sense both the voltage and current for the load? Didn't understand the offline and online power lines, please explain more.

I am now basing on the USB Bit Whacker-18F2553 that you posted.

Thanks

 

[ssembo]

Now let's look at what you propose. You have a 5 KW generator and a 10 KW generator for openers. You closely monitor the demand on the load. If the load exceeds 5 KW you want to switch the load to a 10 KW generator. This looks simple and good on paper but has problems. First, you don't want to run a 5 KW generator under full load constantly, you don't want an instant transfer at 5 KW of load. The 5 KW could just be a spike in demand. You want a delay in there. Maybe like if the load demand exceeds 4.5 KW for several seconds then transfer. Lacking a delay the transfer will freak out (OK get confused) and bang back and forth. Things will get ugly! Additionally if the load is phase sensitive bad things will happen.

Now if the load exceeds 10 KW your options are to bring a 15 KW generator online or combine the 5 KW and 10 KW generators. Remember we are assuming all these generators are up and running. Actually if all the generators are up and running I would just have a single 15 KW generator and be done with it, however, moving along...

Someone mentioned the phasing. You may rest assured that if you have a 5 KW generator and decide to parallel a 10 KW generator lacking perfect sync and control really bad things will happen. You will see sparks, fire and smoke like you never dreamed of.

There are a few considerations in what you want to do or propose and you need to be aware of every one of them. That is what I am saying.

Ron

The issue of the phase difference, i guess can be solved by use of a phase detector sending a signal to amicrocontroller to increase or reduce the speed of the generator until they are in phase then effect the connection. Can't that work?

Ron, i want to use what i learn in this to help me with the other option i have. I want my generator to go on only when there is need (peak demand) from the grid and go off when the load gets down. Used the two generator issue cause someone suggested it and i saw that it could help me here. Switching generator sets has alot involved as have just seen. I have learnt alot from this post.

I have a few questions to ask.

1. Is using a current transformer to sense current a good way to determine load?
2. How is it ensured in practice that the grid and the peak shaver generators/sources are in phase?
3. How is the generator protected from any failures (fail safe mechanism)?
4. What is required for one to make such a peak shaver system, the one that is only on when needed and off when not in use to ensure saving?
5. Which is the best generator type for use?
6. plese indicate as always what can make it a difficult project. indicating its viabilty.

Thanks

Colin

 

[Reloadron]

Using a CT is as good as any other means of measuring current demand. I believe we pretty much beat this to death in another thread. In this thread I provided some thoughts on what is involved with deciding when things should take place. They were only my thoughts for what it's worth. I am not going to beat current transformers to death again.

As to Peak Shaving I am not really that great with commercial grids but the material in this link is a good read. I hope that helps. Interesting story there. You may want to note that for US applications the choice of generators was diesel powered large 4160 volt systems which made for grid comparability but more important compensated for line loss well to sub stations. They placed considerable thought into their decision making process. I would venture a guess that the location (climate) plays a part of the generator decision and the availability of fuel. To say the system chosen for Atlanta, Georgia would likely not be a great choice for Anchorage, Alaska.

Ron

 

[ssembo]

Going to talk to my supervisor about this project. He works in a transmission company, i want to see his opinion. I can do this i believe. Thanks