[time-nuts] Line Frequeny Stablity

[jimlux]

On 4/5/17 11:13 AM, Bill Hawkins wrote:
> The rotary generators in a system of connected generators are
> synchronous
> machines. There is no frequency difference between them, only phase
> angle,
> and not much of that - if the system is stable.
>


Yes.. basically a bunch of coupled oscillators, and unlike the cool 
demos with a bunch of metronomes on a table that self sync, the coupling 
factors among oscillators are not all the same, and the damping of each 
oscillator is different.

Managed historically by people turning a knob and relying on the large 
mass (both literally and figuratively) keeping it from going awry.
If you mess up too much, you get a trip and your generator is offline, 
suddenly, with no load.

Long transmission lines (1000s of km) cause real problems because they 
have time delay that is a significant fraction of a cycle.
So now you have coupled oscillators connected by a transmission line 
(with the characteristics of that transmission line time varying, to a 
certain extent).

Computerized Dispatch (which is what the process of coordinating the 
generation and load is) has been around since the 1960s, but it's not 
perfect.