Why frequency should be constant

It then increases in power until about 10 minutes where it then starts to decline. Secondary Frequency Control is generators on automatic generation control. The final control is the tertiary frequency control which gradually increases in power after ten minutes and levels off at an arbitrary power around 25 minutes. The tertiary frequency control is generators through operator dispatch. The service that we call "frequency regulation" is typically triggered a few minutes after a frequency deviation event, after secondary frequency regulation has kicked in.

In areas that have restructured the utility sector and established competitive markets, frequency regulation is typically procured by system operators through an auction process in advance, similar to the day ahead and real-time energy market. The market operator like PJM announces how much frequency regulation capacity is needed, and generators submit offers to be able to provide that frequency regulation.

This establishes a separate price for frequency regulation. In most electricity markets, offering frequency regulation to the grid operator means that the generator is willing to increase or decrease output known as "regulation up" and "regulation down" by some amount. The ERCOT market in Texas works a little differently, where there are separate markets for regulation up and regulation down.

For example, let's say that a generator with a capacity of MW offered 5 MW of capacity to the regulation market. This means that the generator stands ready to reduce output by 5 MW if needed and to increase output by 5 MW if needed. The payment for regulation has two components. First, generators are paid for the capacity that they dedicate to providing regulation. Second, when a generator is called on to increase or decrease output in response to a frequency deviation event, it is paid for the energy that is produced or not produced.

For example, let's take our same generator providing 5 MW of regulation. Because of a frequency deviation event, the generator is asked to produce an extra 2 MW of power for 10 minutes. The generator's total revenues for this hour would be:. Skip to main content. Figure 9. For the water level to stay constant, inflows must exactly equal outflows. Why should we maintain a constant frequency in the supply system?

Interview Candidate Aug 4th, 5 Electrical Engineering. First Prev Next Last. Showing Answers 1 - 5 of 5 Answers. Stalin Dec 2nd, Rockhy Dec 2nd, Deviation of frequency beyond this band may cause gradual or immediate turbine damage.

Off-nominal frequency operation causes electrical loads to deviate from the desired output. The output of power plant auxiliaries like pumps or fans may reduce, causing reduction in power plant output. At the present, Grid frequency deviation in Indian Grids is generally in between