Sounds like a standard DC power flow to me … see rundcpf() <http://www.pserc.cornell.edu/matpower/docs/ref/matpower6.0/rundcpf.html> and Sections 3.7 and 4.2 of the User’s Manual <http://www.pserc.cornell.edu/matpower/docs/MATPOWER-manual-6.0.pdf>.
Ray > On Jul 17, 2017, at 10:58 PM, Saeed Ahmed <[email protected]> wrote: > > Sir, > Here i try to elaborate my question for your kind guidance > > I want to solve a non linear (AC Power Flow ) Problem using DC approximation > (linear) method which gives estimations of lines power flows on AC power > systems.It is non-iterative and absolutely convergent but less accurate than > AC Load Flow (ACLF) solutions. DC approximation looks only at active power > flows and neglects reactive power flows > > I want to simplify the nonlinear model of the AC system to a linear form > through these assumptions > • Line resistances (active power losses) are negligible i.e. R<< X. > • Voltage angle differences are assumed to be small i.e. sin(h) = h and > cos(h) = 1. > • Magnitudes of bus voltages are set to 1.0 per unit (flat voltage profile). > • Tap settings are ignored. > > > Regards > Saeed Ahmed > > > On 17 July 2017 at 23:41, Ray Zimmerman <[email protected] > <mailto:[email protected]>> wrote: > You can solve the DC power flow using rundcpf(). And MATPOWER does not > include a “WLS” function, so I’m not sure what you are referring to there. > > Ray > > > On Jul 17, 2017, at 9:34 AM, Saeed Ahmed <[email protected] > > <mailto:[email protected]>> wrote: > > > > Hi every one > > > > I need help for solving DC power flow using WLS function. I have tried > > following and need guidance for developing it further. > > > > **************************************************************************************************** > > cd = loadcase('case4gs'); > > casesystem = size(cd.bus, 1); > > cd.bus(:,6) = zeros(length(cd.bus(:,6)), 1) > > cd.branch((cd.branch(:,9) ~= 0),9) = zeros(size(cd.branch((cd.branch(:,9) > > ~= 0),9))); > > pfres = runpf(cd); > > > > TCL MERGE ERROR ( 07/17/2017 10:41:24 ): "invalid command name "Importing"" > OutmailID: 121661759, List: 'matpower-l', MemberID: 78104594 > SCRIPT: "Importing line Data > linedata = cd.branch(:, 1:6); % Calling > "linedata6.m" for Line Data... > linedata(:,6) = ones(size(linedata, 1),1); > > fb = linedata(:,1); % From bus number... > tb = linedata(:,2); % To > bus number... > r = linedata(:,3); % Resistance, R... > x = > linedata(:,4); % Reactance, X... > b = linedata(:,5)./2; % Ground > Admittance, B/2... > a = linedata(:,6); % Tap setting value.. %Assumed 1 > > > y = 1./(r + 1j*x); > > nbus = max(max(fb),max(tb)); % no. of > buses... > nbranch = length(fb); % no. of branches...¨ > >" > Formation of Y-Bus(Admittance) Matrix > > ybus = zeros(nbus,nbus); % Initialise YBus... > > % Formation of the Off-Diagonal Elements... > > for k=1:nbranch > > ybus(fb(k),tb(k)) = ybus(fb(k),tb(k))-y(k)/a(k); > > ybus(tb(k),fb(k)) = ybus(fb(k),tb(k)); > > end > > % Formation of Diagonal Elements... > > for m =1:nbus > > for n =1:nbranch > > if fb(n) == m > > ybus(m,m) = ybus(m,m) + y(n)/(a(n)^2) + 1j*b(n); > > elseif tb(n) == m > > ybus(m,m) = ybus(m,m) + y(n) + 1j*b(n); > > end > > end > > end > > ybus > > > > TCL MERGE ERROR ( 07/17/2017 10:41:24 ): "extra characters after > > close-quote" > OutmailID: 121661759, List: 'matpower-l', MemberID: 78104594 > SCRIPT: "Formation of B-Bus > > Bp=-imag(ybus-diag(sum(ybus))); > > Bpp=imag(ybus) > > **************************************************************************************************** > > > Regards > Saeed Ahmed > > --Apple-Mail=_7E621648-30BB-424D-B739-B09FEBED71AC Content-Transfer-Encoding: > quoted-printable Content-Type: text/html; charset="utf-8" > <html><head><meta http-equiv="Content-Type" content="text/html > charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: > space; -webkit-line-break: after-white-space;" class="">You can solve the DC > power flow using <font face="Courier" class="">rundcpf()</font>. And MATPOWER > does not include a “WLS” function, so I’m not sure what you are referring to > there.<div class=""><div class=""><br class=""></div><div class=""> > Ray</div><div class=""><br class=""><div><blockquote type="cite" > class=""><div class="">On Jul 17, 2017, at 9:34 AM, Saeed Ahmed <<a > href="mailto:[email protected] <mailto:[email protected]>" > class="">[email protected] <mailto:[email protected]></a>> > wrote:</div><br class="Apple-interchange-newline"><div class=""><div > dir="ltr" class=""><div class="gmail_default" style="font-family: tahoma, > sans-serif; font-size: small;">Hi every one </div><div > class="gmail_default" style="font-family: tahoma, sans-serif; font-size: > small;"><br class=""></div><div class="gmail_default" style="font-family: > tahoma, sans-serif; font-size: small;">I need help for solving DC power flow > using WLS function. I have tried following and need guidance for developing > it further.</div><div class="gmail_default" style="font-family: tahoma, > sans-serif; font-size: small;"><br class=""></div><div class="gmail_default" > style="font-family: tahoma, sans-serif; font-size: > small;">****************************************************************************************************</div><div > class="gmail_default"><div class="gmail_default"><font face="tahoma, > sans-serif" class="">cd = loadcase('case4gs');</font></div><div > class="gmail_default"><font face="tahoma, sans-serif" class="">casesystem = > size(cd.bus, 1);</font></div><div class="gmail_default"><font face="tahoma, > sans-serif" class="">cd.bus(:,6) = zeros(length(cd.bus(:,6)), > 1)</font></div><div class="gmail_default"><font face="tahoma, sans-serif" > class="">cd.branch((cd.branch(:,9) ~= 0),9) = > zeros(size(cd.branch((cd.branch(:,9) ~= 0),9)));</font></div><div > class="gmail_default"><font face="tahoma, sans-serif" class="">pfres = > runpf(cd);</font></div><div class="gmail_default"><font face="tahoma, > sans-serif" class=""><br class=""></font></div><div > class="gmail_default"><font face="tahoma, sans-serif" class="">" > Importing line Data</font></div><div class="gmail_default"><font > face="tahoma, sans-serif" class="">linedata = cd.branch(:, 1:6); % Calling > "linedata6.m" for Line Data...</font></div><div class="gmail_default"><font > face="tahoma, sans-serif" class="">linedata(:,6) = ones(size(linedata, > 1),1);</font></div><div class="gmail_default"><font face="tahoma, sans-serif" > class="">fb = linedata(:,1); % From bus > number...</font></div><div class="gmail_default"><font face="tahoma, > sans-serif" class="">tb = linedata(:,2); % To bus > number...</font></div><div class="gmail_default"><font face="tahoma, > sans-serif" class="">r = linedata(:,3); % Resistance, > R...</font></div><div class="gmail_default"><font face="tahoma, sans-serif" > class="">x = linedata(:,4); % Reactance, > X...</font></div><div class="gmail_default"><font face="tahoma, sans-serif" > class="">b = linedata(:,5)./2; % Ground Admittance, > B/2...</font></div><div class="gmail_default"><font face="tahoma, sans-serif" > class="">a = linedata(:,6); % Tap setting value.. > %Assumed 1</font></div><div class="gmail_default"><font face="tahoma, > sans-serif" class=""><br class=""></font></div><div > class="gmail_default"><font face="tahoma, sans-serif" class="">y = 1./(r + > 1j*x);</font></div><div class="gmail_default"><font face="tahoma, sans-serif" > class=""><br class=""></font></div><div class="gmail_default"><font > face="tahoma, sans-serif" class="">nbus = max(max(fb),max(tb)); > % no. of buses...</font></div><div class="gmail_default"><font > face="tahoma, sans-serif" class="">nbranch = length(fb); > % no. of branches...¨</font></div><div > class="gmail_default"><font face="tahoma, sans-serif" class=""><br > class=""></font></div><div class="gmail_default"><font face="tahoma, > sans-serif" class="">TCL MERGE ERROR ( 07/18/2017 10:26:26 ): "wrong # args: > should be "for start test next command"" OutmailID: 121664038, List: 'matpower-l', MemberID: 75174736 SCRIPT: "Formation of Y-Bus(Admittance) Matrix</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class="">ybus = zeros(nbus,nbus); % Initialise YBus... </font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> % Formation of the Off-Diagonal Elements...</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> for k=1:nbranch</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> ybus(fb(k),tb(k)) = ybus(fb(k),tb(k))-y(k)/a(k);</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> ybus(tb(k),fb(k)) = ybus(fb(k),tb(k));</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> end</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> % Formation of Diagonal Elements...</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> for m =1:nbus</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> for n =1:nbranch</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> if fb(n) == m</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> ybus(m,m) = ybus(m,m) + y(n)/(a(n)^2) + 1j*b(n);</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> elseif tb(n) == m</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> ybus(m,m) = ybus(m,m) + y(n) + 1j*b(n);</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> end</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> end</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> end</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> ybus</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> </font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> " Formation of B-Bus</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> </font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> Bp=-imag(ybus-diag(sum(ybus)));</font></div><div class="gmail_default"><font face="tahoma, sans-serif" class=""> Bpp=imag(ybus)</font></div></div><div class="gmail_default" style="font-family: tahoma, sans-serif; font-size: small;">****************************************************************************************************<br class=""></div><div class="gmail_default" style="font-family: tahoma, sans-serif; font-size: small;"> </div><div class=""><div class="gmail_signature"><div dir="ltr" class=""><div dir="ltr" class=""><div class=""><font face="arial narrow, sans-serif" size="4" class="">Regards</font></div><div class=""><font face="arial narrow, sans-serif" size="4" class="">Saeed Ahmed</font></div><div class=""><br class=""></div></div></div></div></div> > </div> > </div></blockquote></div><br class=""></div></div></body></html> >
