Article View: alt.engineering.electrical
Article #361Re: Electric Energy Economizer !!
From: daestrom
Date: Sun, 11 Jan 2004 21:24
Date: Sun, 11 Jan 2004 21:24
35 lines
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4112 bytes
"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message news:SnQh$7BXKFAAFwqV@jmwa.demon.co.uk... > I read in sci.engr.electrical.compliance that Keith R. Williams > <krw@attglobal.net> wrote (in <MPG.1a69fc3413cbc9d198aa9f@enews.newsguy. > com>) about 'Electric Energy Economizer !!', on Sat, 10 Jan 2004: > > >Again, I understood that short lines were slightly capacitive > >(can be a good thing since large loads tend to be inductive) and > >that long lines were highly inductive (bad). ...or did I miss > >the boat here? > > No, you are right. But it's not a straightforward 'good/bad' thing. By > itself, the line inductance can't cause instability. It does cause a > voltage drop, and thus contributes to MVAr. I don't completely agree with 'the line inductance cant cause instability'. The line inductance is the major factor limiting the amount of *real* power than can be transferred/carried through many lines. With the voltage allowed at each end of a line determined by other considerations, the amount of real power that a line carries is a function of voltage at each end, phase difference and line impedance (classic four-terminal network problem). If the line characteristic suddenly changes (such as a capacitor tripping off or one of several parallel lines isolating), the max power that can be transferred will drop sharply. If the power angle needed to carry the real power exceeds 90 degrees, the system pulls out of sync and becomes very unstable. And the line inductance is a major part of that equation. Most people don't realize the line inductance for long lines is more of a problem than the resistance. Lose the compensating capacitor banks, or the voltage support equipment and the thing quickly becomes unstable. daestrom
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 109f9b,5bf874aa96b72978 X-Google-Attributes: gid109f9b,public X-Google-Thread: 103407,5bf874aa96b72978 X-Google-Attributes: gid103407,public X-Google-Thread: fd33a,5bf874aa96b72978 X-Google-Attributes: gidfd33a,public X-Google-Thread: fafc9,5bf874aa96b72978 X-Google-Attributes: gidfafc9,public X-Google-Thread: 10d137,5bf874aa96b72978 X-Google-Attributes: gid10d137,public X-Google-ArrivalTime: 2004-01-11 13:25:05 PST Path: arc1-ca.pugleaf.net!archiver1.google.com!news2.google.com!news.maxwell.syr.edu!news-rtr.nyroc.rr.com!news-out.nyroc.rr.com!twister.nyroc.rr.com.POSTED!53ab2750!not-for-mail From: "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> Newsgroups: alt.engineering.electrical,aus.electronics,misc.industry.utilities.electric,sci.engr.electrical.compliance,sci.engr.electrical.sys-protection References: <bt578b$3fofj$5@ID-174448.news.uni-berlin.de> <ipqJb.29$9k7.14451@news.xtra.co.nz> <wbtJb.20877$nK2.18044@nwrddc01.gnilink.net> <NBDJb.589770$0v4.23349050@bgtnsc04-news.ops.worldnet.att.net> <urpevv82k3r0trnb0jh762fs98hn2i8a6s@4ax.com> <3ff785d4@news.rivernet.com.au> <nt8fvv8pga4ir6caokf25nspfbhehp74dt@4ax.com> <CD_Jb.280057$Ec1.9613771@bgtnsc05-news.ops.worldnet.att.net> <bt9vr6$4tmu9$1@ID-103962.news.uni-berlin.de> <yo0Kb.597415$0v4.23524771@bgtnsc04-news.ops.worldnet.att.net> <oj4v+tAOlR+$EwCo@jmwa.demon.co.uk> <MPG.1a63df869880ac1998aa6b@enews.newsguy.com> <Io_Kb.125403$JW3.65999@twister.nyroc.rr.com> <W6Yw4pAKaI$$Ew9l@jmwa.demon.co.uk> <MPG.1a669c8b86c0234c98aa8f@enews.newsguy.com> <m5bMIdAHnb$$EwrC@jmwa.demon.co.uk> <MPG.1a67d2fd6df25e8198aa98@enews.newsguy.com> <a0TTLfBkLm$$Ew8a@jmwa.demon.co.uk> <MPG.1a69fc3413cbc9d198aa9f@enews.newsguy.com> <SnQh$7BXKFAAFwqV@jmwa.demon.co.uk> Subject: Re: Electric Energy Economizer !! Lines: 37 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2800.1158 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Message-ID: <DajMb.138431$JW3.88608@twister.nyroc.rr.com> Date: Sun, 11 Jan 2004 21:24:51 GMT NNTP-Posting-Host: 24.58.98.160 X-Complaints-To: abuse@rr.com X-Trace: twister.nyroc.rr.com 1073856291 24.58.98.160 (Sun, 11 Jan 2004 16:24:51 EST) NNTP-Posting-Date: Sun, 11 Jan 2004 16:24:51 EST Organization: Road Runner