[Milsurplus] Even Worse

Mon Jul 5 14:16:52 EDT 2010

The real issues in network stability are that, because of the large
rotating inertias of generators, a rapid phase change is all but
impossible. To change the phase of a machine with respect to the network,
you have to speed it up a tad (more steam), let the phase change, and then
slow it back down (less steam). This cannot be done quickly.

Furthermore, in a simplified case, if you have just two AC generators
connected together, the can "rock" against each other in phase (rocking is
a variation of the relative phase of the rotors), and the rocking is very,
very lightly damped. Extend this issue to a network with hundreds of
machines and you have a giant mess.

-John

=================

> The real use of synchrophasors is not for power setting (that can easily
> be done by far less complex methods) but for early indication of grid
> disturbances.  This is getting more valuable as the control of the grid
> is moving to a model-based design.  Humans just can't interpret and
> respond fast enough to prevent cascading problems.
>
> Peter
>
>
> J. Forster wrote:
>> Ah, yes. Phase shifting is easy in a polyphase system. For example, a
>> Scott connected transformer can change 2 phase to 3 phase, or the
>> inverse.
>>
>> Thanks,
>>
>> -John
>>
>> ==============
>>
>>
>>
>>> Yes, it's done with a specialized tap-changing transformer called a
>>> Phase
>>> Angle Regulator.  This paper describes how they're used:
>>> http://www.npcc.org/viewDoc.aspx?name=Phase+Angle+Regulator+Operation+-May+2
>>> 000.pdf&cat=LEER
>>>
>>> Albert
>>>
>>> -----Original Message-----
>>> From: milsurplus-bounces at mailman.qth.net
>>> [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Larry Godek
>>> Sent: Sunday, July 04, 2010 6:10 PM
>>> To: nerd at verizon.net; Milsurplus at mailman.qth.net
>>> Subject: Re: [Milsurplus] Even Worse
>>>
>>> Do power companies share power back and forth according to peak periods
>>> by
>>> changing the phase slightly?  Where did i come up with this idea?  I
>>> really
>>> don't remember.
>>>
>>> Larry
>>> W0OGH
>>>
>>>
>>> --- On Sat, 7/3/10, Peter Gottlieb <nerd at verizon.net> wrote:
>>>
>>> From: Peter Gottlieb <nerd at verizon.net>
>>> Subject: Re: [Milsurplus] Even Worse
>>> To: jcoward5452 at aol.com
>>> Cc: jfor at quik.com, milsurplus at mailman.qth.net
>>> Date: Saturday, July 3, 2010, 1:46 PM
>>>
>>> The power companies already do that and is able to compare phasors
>>> across the grid.  Check out NASPI, the North American SynchroPhasor
>>> Initiative.
>>>
>>> I set up a PMU (Phasor Measurement Unit) at my plant already, it uses
>>> GPS for time sync.
>>>
>>> Peter
>>>
>>>
>>>
>>> jcoward5452 at aol.com wrote:
>>>
>>>> Here at our secret development Lab, we phase lock the 60~ to a GPS
>>>>
>>> receiver. This is how you make all the frequencies in the audio
>>> spectrum
>>> exact. This is really no secret as most Laboratories have a "house"
>>> standard
>>> derived from a GPS receiver.
>>>
>>>>   Jay
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: J. Forster <jfor at quik.com>
>>>> To: Richard Brunner <brunneraa1p at comcast.net>
>>>> Cc: milsurplus <milsurplus at mailman.qth.net>
>>>> Sent: Sat, Jul 3, 2010 1:06 pm
>>>> Subject: Re: [Milsurplus] Even Worse
>>>>
>>>>
>>>> There is a thread on another list about radioactive tubes. I replied:
>>>> "And, isotopically pure Thorium likely costs $millions / pound.
>>>> What an opportunity for the Audiophools! Now, your Tube Amp can be
>>>> onstructed with eviro-pure tubes. No harmful radiation to contaminate
>>>> the
>>>> larity of the sound. We at, PT Barnam AudioLabs, use only isotopically
>>>> ure Thorium cathodes!!"
>>>> :-)))
>>>> -John
>>>> =============
>>>>
>>>>
>>>>   This is beyond witless. Who are these people with so much money and
>>>> so
>>>>   little sense?  I notice they also can't spel, so it's consistent.
>>>>   Imagine, three brass spikes!
>>>>
>>>>   Richard, AA1P
>>>>
>>>>
>>>>   On Sat, 2010-07-03 at 08:57 -0700, J. Forster wrote:
>>>>
>>>>
>>>>> http://www.cruzefirstaudio.com/tripoint.htm
>>>>>
>>>>>
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>>
>>
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