David F Mayer said:

>As far as security is concerned, the power failures of recent
>years have been due largely to the instability of the AC power
>grid. It is high time to upgrade to a DC power grid, which is
>inherently more stable. The thing that makes AC grids unstable
>is the need for synchronization. When load changes drastically,
>part of the grid tends to go out of phase with the rest, which
>then causes breakers to pop. DC has no sychronization problem.
>I am proposing DC for TRANSMISSION only, NOT for
>DISTRIBUTION of power. Distribution is best handled by AC
>because it is much easier to change voltage of AC than DC.

A friend of mine who is an electrical engineer told me that creating extremely large stable power grids maybe an unsolvable problem. He then told me that there was an attempt to create a single power grid for the entire United States but the effort was abandoned because they could not make it stable. He described the problem being rooted in undamped oscillations forming within grid.

It is my understanding that AC power transmission is unavoidable due to the need for high voltage transmission. Supposably the transmitted power losses over distance go down as voltage increases. As power reaches the end consumer, the voltage needs to be stepped down to permit safe usage. This is easy to do if the power is AC (use ordinary transformers) but expensive if DC. If they could crack the problem of room temperature superconducting, that would change everything in terms of power transmission.

Gary
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