About a week ago I received a number of requests for an explanation of how the grid works, and in particular how something that industry proffessionals say is simple can appear so complex to the layman.

I have attempted to do that in a post on TB200 called Electricity Generation and Distribution 101. I have tried to reduce the whole idea of the electricity system to its most basic form while covering all aspects from the boiler to the home. This has caused me to try and explain some items that I am not expert on, and I would appreciate it if anyone here with detailed knowledge on distribution systems in USA, and/or modern digital control systems could glance in from time to time and assist with answering any questions.

Malcolm

-- Anonymous, November 04, 1999

Answers

Hi Malcolm. A few of your countrymen came up and spoke here in the USA about how NZ will be providing information on December 31, being the first English-speaking industrialized country to roll over. It will be greatly appreciated, and as you know, the world will be watching...

Anyway, I don't have much familiarity with digital control systems, but I do have a good deal of experience with distribution systems. Some analogies that helped me in college, that might be useful to the non-power engineer, include:

Explaining reactive power (the beer "head" is Vars; the beer is Watts)

Voltage is potential energy, like a rock on a hill; similarly, current is kinetic energy, as in the rock rolling down the hill.

Distribution systems are radial in nature, like the octopus, as opposed to transmission systems, which are looped.

Electron flow (current) can be represented as worker ants walking along the power line--too much current means too many ants, and the voltage (and line) will "sag".

Whaddya think?

-- Anonymous, November 04, 1999

Dan,

That sounds like you are explaining how the electric system works in Russia or South America. Is this also the way it really works here? I thought we were supposed have a system that was like a water hose, rather than an army ant column. Maybe it could be put on a Mr.Rogers show on PBS, as a sequel to The Winter of Our Disconnect. Seems simple enough.

-- Anonymous, November 04, 1999

Gordon, I assure you, I was not trying to insult anyone's intelligence with my analogies. I was merely using the ones that helped me the most when I was learning. I've read some of your other posts, and I know that you have some electrical background.

By the way, I see Connectiv is still listed as ready with exceptions.

-- Anonymous, November 05, 1999

Dan,

I was making that comment above with tongue in cheek, as you can see. And regarding Conectiv (silly spelling they chose, they need to expand the code for another n) they keep me very alert to possible problems here. The major concern for me is that the parent, holding company, Conectiv did not get serious enough about the Y2k situation until this year. They started working on accounting systems last year, must not a whole lot more. Typical mega corporation business approach, and not the "old line" approach of an electric utility with good management that really cares.

-- Anonymous, November 06, 1999

Malcom, I think I saw what was your first post at TB2000, a great job of posting factual information regarding Y2K and electric power, and a very good reception in that forum!

Have you posted others? I may have missed them. You might want to put links to previous posts when you post, so it's all "tied" together...

I am not an expert on T&D, but perhaps can help on control systems, depending on the manufacturer/systems/etc. I lost the original thread you posted, but if I remember correctly, you may have indicated that generator voltage regulation was analog (since digtal was too slow or something like that). For the installed base, most are indeed older analog.

Most voltage regulators/excitation systems manufactured today however are digital, and they are quite fast enough to control the response of the generator (which has a relatively slow time response compared to the controllers speed). In the US, only Westinghouse is still making large analog VRs (and they have digital as well). Also GE makes only a digital system for larger main generators. Basler still makes some analogs. Internationally ABB, Alstom all make digital exitation systems.

Regards,

-- Anonymous, November 09, 1999

Factfinder, Many thanks for your comments, they are much appreciated. The original thread is still alive at Generation and Distribution 101

http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=001fmA

Malcolm

-- Anonymous, November 10, 1999