Power Plants and Micro-Regulation

[Frank Peters]

Electrical generation plants produce large amoounts of power to serve millions of people and many thousands of factories. I know very little about how such power is regulated and I always wonder how such large power output can be instantly regulated to accommodate the many instant changes in consumption that undoudtedly occur throughout the power grid.

The problem, to me, is this:

If I switch on or off a light or an appliance in my home this action constitutes a change, although minute, on the total load. If a thousand, or ten thousand, people do this within a short time interval then the change in load can become more significant. Because of these various activities there must be tremendous numbers of load changes, both large and small and for varying times, throughout the day.

Can a huge power generation plant respond to all of those load changes? I would suspect that it cannot, at least not immediately.

Then what happens to the grid when more power is suddenly demanded? Does the grid voltage drop?

I suspect that the grid voltage varies continually due to the inability of the power plant to rapidly adjust the output to meet quickly changing loads. Would this be a correct suspicion?

There is also the question of reactive power. Is there reactive power present on the grid to accommodate changes in load?

Any insight into this matter would be much appreciated.

 

[anorlunda]

You asked those questions at the right place. It just so happens that we have a PF Insights article that addresses just that. Even the title: What Happens When You Flip the Light Switch?
https://www.physicsforums.com/insights/what-happens-when-you-flip-the-light-switch/

There are also articles that explain reactive power. And yes, we do use reactive power, but maybe not the way you thought.
https://www.physicsforums.com/insights/ac-power-analysis-part-1-basics/
https://www.physicsforums.com/insights/ac-power-analysis-part-2-network-analysis/