The electricity power grid is the physical system that delivers electricity from the place where it is generated to the site where it is used.
Basic concepts:
From Energy Explained, read How Electricity is Delivered to Consumers [5] (updated Dec 2016)
The Power Grid is a simulation applet, developed at the University of Illinois in partnership with The Office for Mathematics, Science, and Technology Education (MSTE) in the College of Education and the Information Trust Institute.
User Guidelines
When the applet opens, power is being produced by four of the five generators. You can see the power moving from the generators through the substations and to the users in the Communities of Commerceton, Industryville, and Residenceburg.
Any power that is not used by the communities is sent to users in other systems. If the generators are not producing enough power, power will be purchased from other systems. In the applet this is indicated by the two External Systems. (This simulation is designed to blackout if both External Systems are disconnected from the system.)
The arrows show the direction the power is moving. The current is flowing out of the generators, through the substations and into the communities. Bigger arrows indicate more power.
The transmission lines in the applet have varying capacities. They range from 1000 MW to 2000 MW. The line flow for each line is noted near the line and changes as the power flow changes. (When a line is carrying less than 85% of its capacity, the arrows are green, indicating that the flows are within normal operating conditions. As the flow moves past 85% of the line capacity, the arrows turn orange, indicating that the lines should not be made to carry much more power. As the flow continues to increase past the maximum, the arrows turn red.) If a line remains overloaded for approximately 10 seconds, it automatically opens and a notification is displayed.
If a community demands more power than the transmission line that serves it can carry, the community will blackout. A community may also blackout if a line is damaged. In the applet as well as in reality, a transmission line problem in one area of the system can cause blackouts in several areas.
There are five generators represented in this simulation. The coal, hydropower and natural gas generators have adjustable outputs. The others do not. Click on the up and down arrows to the right of MW output labels to change the production.
While wind's output cannot be adjusted, its variation can be set from "none" to "High" using the slider below the system graphic.
All of the generators have connection switches that you can open or close.
Links
[1] https://www.youtube.com/watch?v=1dZjohZPIqE#t=128
[2] http://burnanenergyjournal.com/about-burn/
[3] https://www.e-education.psu.edu/egee401/sites/www.e-education.psu.edu.egee401/files/image/lesson05/BetterGrid_LD.html
[4] http://energy.gov/oe/office-electricity-delivery-and-energy-reliability
[5] http://www.eia.gov/energyexplained/index.cfm?page=electricity_delivery
[6] https://credc.mste.illinois.edu/applet/pg