EU residents might have noticed that some of the clocks in their house have been running out of sync with other clocks. Apparently, the cause for this is that power suppliers had to reduce the frequency at which the AC network alternates the current flow. I understand that the speed at which these clocks tick is based on the frequency of the AC network, so thus far it makes sense. The thing I don't understand is that according to reports, the reason the power suppliers had to reduce the frequency was because a regional provider in the Balkan did not provide their fair share of power to the grid. I read the article of the Swiss power grid website at https://www.swissgrid.ch/swissgrid/en/home/experts/topics/frequency.html which states:
If the consumption of electrical power is lower than production, the frequency is higher; if consumption is higher than production, the frequency is lower. The reason for this is as follows: the electrical generators of an electricity grid rotate more readily and faster when consumption is low. Consequently, they rotate with a higher frequency. Conversely, the electrical generators rotate more laboriously and with a lower frequency when consumption is greater.
So the generators have to rotate at a slower pace if demand is greater than supply. Why? I mean, I don't even understand how the grid remains functional if demand is greater than supply. usually if demand is greater than supply, part of the demand doesn't get fulfilled. I might misunderstand how the power grid as a whole deals with a situation like that. I especially don't understand what the link is between the undersupply on the grid and the mechanical speed of the generators. I know basically nothing about the power grid, so that doesn't help either.
Best Answer
That is not exactly true. Power torque X speed. To increase power it is not necessary to increase speed; torque can be increased. Torque is increased by increasing the throttle setting. All generation systems have some kind of throttle mechanism. However, the operation of the throttle is not instantaneous. That leads to a brief reduction in speed when the load (demand) increases. As the various generators connected to the grid slow down, their throttles are automatically adjusted to correct the speed decrease. Electrical grids generally have enough reserve capacity to handle the increased demand. If there is not enough reserve, the voltage and frequency drop may persist for an longer time.
When the demand drops, the generators will run faster than normal for a brief period. That would tend to correct the clocks so that there would be little or no net error over the course of 24 hours. However, if the grid capacity is not sufficient, extended periods of reduced voltage and frequency will result.