Electric Utility Companies are divided into three distinct subgroups. These groups are Generation, Transmission and Distribution. There is also another group that power companies utilize that monitor and control all of these subgroups. This group is usually called the System Operations group or something similar.
This group consists of the power companies’ power generating resources. These can include coal, gas, oil, nuclear, hydro, diesel, wind, solar power plants and more. Each of these facilities relies on diesel backup power for transient periods and outages. The electricity that these Power Plants produce is automatically controlled under instructions from the System Operations Group. This automatic control is usually accomplished using something called Automatic Generation Control or AGC for short. AGC controls the megawatt output, frequency, and regulates the voltage and VAR (volt amp reactance) output of the generating units. The Generation group also contains sub-groups which are the support that go along with these Power Plants and these include Operations, Maintenance and Engineering and there are many departments to these three entities (Warehousing, Safety, Environmental, Fuels, Training, Human Resources and Labor Relations to mention a few).