Why not turn off power grid one hour before hurricane sandy ?

It's NYC... what else can I say? ...Jim Thompson

Skybuck Flying schrieb:

Hello,

if you want to restore power after the hurricane as quickly as possible, you have to test a lot of high voltage components for damages, water and ground faults. If you don't test all components, may be some parts will blow up when power is restored again. It is difficult to find a strategy that both saves time to restore power and keeps the number of destroyed components low. Customers will protest if power is turned off long before the hurricane hits the city.

Bye

Life Support applications. You just forced a transfer to a short lived back up source. Not to mention the massive startup surge needed when dumping power into rotary loads.

Steve

source. Not to mention the massive startup surge needed when dumping power into rotary loads.

Or what dropping that much load all at once would do the the generators.

You would think that they (power companies) would have thought of that.

This is not the first time power has gone out on a massive scale.

How did it come up the last time ?

Actually they did shut down the generators that they expected to get flooded. The idea was they didn't want the cold water to hit the steam. However, this storm produced water levels that exceeded predictions. As you know, there is 4% more water vapor in the atmosphere now as compared to 40 years ago. So your once in a century storms are now much more common.

Power companies think about this a lot. The trouble is that no matter how much you think about it, the physics don't change.

My understanding is that they bring power up in smaller pieces to prevent overloading the generation capabilities. As to shutting down the power before? Well, I think the damage caused by leaving the power on may be less than the damage done by turning it off.

Rick

Are there no laws of physics on your world? Sudden loss of load on those huge generators cause them to speed up, and can destroy the turbines, or bearings.

When has New York City ever gone down all at once? There have been cascade failures with area after area disconnecting from the grid as the system failed, but never the whole city. It takes a long time to synchronize a grid that size, and a long time to shut it down without damage.

Yeah, not as if the overspeed protection would work !!

Not to worry. Only black helicopters are dangerous.

The small nuclear power plant at Greely was overspun several times. Each time required the turbine to be dismantled and shipped stateside for overhaul. They finally decommissioned the plant.

Circuit breakers trip all the time. The generators are pretty well protected.

Big generator-type steam turbines usually have load-loss (like, broken shaft unload) time constants in the 2-8 second range, so overspeed shutdown has to be in a fraction of a second. On ships that I used to work on, I was told that if the HP turbine was unloaded at full power (broken shaft or stripped gear) it was going to come apart. As long as it was coupled to the LP turbine and stuff, the overspeed trips would protect it.

Too bad they missed!

Jamie

Did they find some real engineers for the next one ??

The problem was a lack of communication between the power plants on Alaska's power grid. They would add or drop generators without warning other facilities. That was the smallest nuke power plant, and an experimental system to see how it held up in subzero weather. The engineers were trained for the job, but there was too much ego in the operators of the other plants. At least Greely kept their diesel power plant as a backup, and reverted to it after the nuke was shut down for good.

Niagara Falls is hydro, not steam. They have to be carful of jackhammer, and flooding the plant if a supply line ruptures.

Crikey guys, the entire East side of North America is interconnected. You could shut off the entire state of New York without damaging any equipment as long as you dumped load sequentially and rebalanced generation as you went along.

It all takes time. Even the cascading blackout of 2003 took place over 4 hours, and then it took a couple of days to get it all back up, even though little had actually been damaged.

Also power outages themselves cause deaths. People burn their houses down with candles, or die from carbon monoxide poisoning by running generators indoors.

Sylvia.

Darwin at his best. The gene pool often needs more chlorine.