How does power spikes work?
November 3, 2011 11:45 PM Subscribe
Calling all electricians: please explain to me how power surges work.
posted by Hakaisha to Technology (4 answers total) 2 users marked this as a favorite
All right, I sort of understand the basic principles. Sudden boost of electrical charge somewhere across the power lines causes an increase in the potential, increasing current to the wall sockets.
For something like a lightening strike, this makes sense to me. Sudden boost in energy (current/voltage), transmit across power lines (blowing through all failsafes), blows up everything in their way. Okay.
But the more mundane examples escape me. E.g. power outages. The electricity reaching my house during a power outage is zero, so yes, there is a difference in electrical potential compared to electricity from the source/plant...but surely within the complex power grid there are transformers and capacitors and other -er's that changes the tons of energy coming from the power plant into the usual household voltage and current. Is it simply those failsafes are overloaded by a power outage, and if so, why? If the power plant had stopped and then started (making a humongous difference in potential), or as the lightning strike example above, I can see that sheer amount of energy being problematic. A short duration of power outage should be within the electrical grid's capabilities, right? Why would it cause an issue with my electronics?
An example from today: an electrician from the power company was fiddling with my meter and shut off power to my house for 10-20 seconds. My phone was plugged into the wall. Does 0 energy reaching my phone, and then the sudden availability of electricity again, create a power differential as to damage it? (My phone actually has had spotty internet but okay voice service for about 20 minutes in the morning after the 10s shutoff, was fine in the afternoon, and now is erratic again, but I think that's my provider). I'd assume the power grid can handle this, but power outages are frequently warned for causing spikes. And my brain is trying to relate this to on/off of electronics in general somehow. So, if I turn my computer off, 0 energy is reaching my computer...so the "surge" of electricity when I turn it (or any electronic) on might be enough to damage it? That makes no sense, but it sounds kind of (faultily) logical from the above train of thought...
Also, internet googling tells me that just heavy use of the electrical circuit (heavy machinary, appliances that use a lot of energy, etc) causes dips and recoveries in the electricity available to the house, acting like another form of surges, and can slowly damage the electric wiring in the house. But if my hairdryer works with a typical socket at 110V, and less energy is reaching my hairdryer because the dryer (or air con, or elevator, or whatever) is on, then once the dryer is off the voltage flow returns to its 110V maximum which should be what it's designed for, so how these 'mini surges" induce (gradual) damage in the system is also a mystery to me.
I'm actually embarrassed to ask this because I somehow managed to get decent to excellent grades in physics classes all my life, but obviously the wisdom imparted was not wholly understood. Google gave me the general principles listed in the first paragraph, but doesn't further my understanding. Enlighten me, Mefites!