matlab.rar_Power System matlab_power engineering_power system

function power_flow(filename) %POWER_FLOW Function to perform a power-flow analysis. % Function power_flow reads a data set describing a power system % from a disk file, and performs a power-flow analysis on it. % The only argument is the name of the input file. There are % three types of lines in the input file. The "SYSTEM" line % specifies the name of the power system and the base apparent % power of the power system in MVA. Its form is: % % SYSTEM name baseMVA tol % % where % name = The name of the power system % baseMVA = The base MVA of the power system % tol = Voltage tolerance % % The "BUS" line specifies the characteristics of a bus on the % power system. Its form is: % % BUS name type volts Pgen Qgen Pload Qload Qcap % % where % name = The name of the bus % type = The type of the bus, one of PQ, PV, or SL % Vbus = The initial voltage guess for PQ busses % The fixed magnitude of voltage PV busses % The fixed magnitude at an angle of 0 deg for Sl busses % Pgen = Is the real power generation in MW at the bus % Qgen = Is the reactive power generation in MVAR at the bus % Pload = Is the real power load in MW at the bus % Qload = Is the reactive power load in MVAR at the bus % Qcap = Is the reactive power of capacitors in MVAR at the bus % % The "LINE" line specifies the characteristics of a transmission % line on the power system. Note that the impedance of the % transformers in series with the transmission line should also % be lumped into these terms. Its form is: % % LINE from to Rse Xse Gsh Bsh Rating % % where % from = The name of the "from" bus % to = The type of the "to" bus % Rse = Per-unit series resistance % Xse = Per-unit series reactance % Gsh = Per-unit shunt conductance % Bsh = Per-unit shunt susceptance % Rating = Max power rating of the line in MVAR % % The lines should appear in the order: % % SYSTEM ... % BUS ... % LINE ... % % The program reads the data from the input file and solves for the % voltages at every bus. Then, it generates a report giving the % voltages and power flows throughout the system. % Record of revisions: % Date Programmer Description of change % ==== ========== ===================== % 01/12/00 S. J. Chapman Original code % Get the power system data [bus, line, system] = read_system(filename); % Byild Ybus ybus = build_ybus(bus, line); % Solve for the bus voltages [bus, n_iter] = solve_system(bus, ybus); % Display results report_system(1, bus, line, system, ybus, n_iter); %================================================================ %================================================================ function [bus, line, system] = read_system(filename) %READ_SYSTEM Read a power system from disk. % Function read_system reads a data set describing a power system % from a disk file. There are three types of lines in the input % file. The "SYSTEM" line specifies the name of the power system % and the base apparent power of the power system in MVA. Its % form is: % % SYSTEM name baseMVA tol % % where % name = The name of the power system % baseMVA = The base MVA of the power system % tol = Voltage tolerance % % The "BUS" line specifies the characteristics of a bus on the % power system. Its form is: % % BUS name type volts Pgen Qgen Pload Qload Qcap % % where % name = The name of the bus % type = The type of the bus, one of PQ, PV, or SL % Vbus = The initial voltage guess for PQ busses % The fixed magnitude of voltage PV busses % The fixed magnitude at an angle of 0 deg for Sl busses % Pgen = Is the real power generation in MW at the bus % Qgen = Is the reactive power generation in MVAR at the bus % Pload = Is the real power load in MW at the bus % Qload = Is the reactive power load in MVAR at the bus % Qcap = Is the reactive power of capacitors in MVAR at the bus % % The "LINE" line specifies the characteristics of a transmission % line on the power system. Note that the impedance of the % transformers in series with the transmission line should also % be lumped into these terms. Its form is: % % LINE from to Rse Xse Gsh Bsh Rating % % where % from = The name of the "from" bus % to = The type of the "to" bus % Rse = Per-unit series resistance % Xse = Per-unit series reactance % Gsh = Per-unit shunt conductance % Bsh = Per-unit shunt susceptance % Rating = Max power rating of the line in MVAR % % The lines should appear in the order: % % SYSTEM ... % BUS ... % LINE ... % Record of revisions: % Date Programmer Description of change % ==== ========== ===================== % 01/12/00 S. J. Chapman Original code % Check for a legal number of input arguments. msg = nargchk(1,1,nargin); error(msg); % Initialise counters n_system = 0; % Number of SYSTEM cards n_bus = 0; % Number of BUS cards n_lines = 0; % Number of LINE cards n_bad = 0; % Number of INVALID cards n_comment = 0; % Number of comment lines i_line = 0; % Current line number %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Open input file %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [fid,message] = fopen(filename,'r'); % FID = -1 for failure. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Check for error %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if fid < 0 str = ['ERROR: Can''t find system file: ' filename]; error(str); else %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % File open OK, so read lines. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% while feof(fid) == 0 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Get next line %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% data = fgetl(fid); i_line = i_line + 1; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Extract keyword %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% maxlen = min( [ 6 length(data) ] ); keyword = data(1:maxlen); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Determine the type of the line %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if strncmpi(keyword,'SYSTEM',6) == 1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % This is a SYSTEM card %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% n_system = n_system + 1; % Get system name blanks = findstr(data,' '); test = diff(blanks) > 1; for ii = 1:length(test) if test(ii) > 0 system.name = data(blanks(ii)+1:blanks(ii+1)-1); break; end end % Get base MVA ii = blanks(ii+1); temp = sscanf(data(ii:length(data)),'%g'); system.baseMVA = temp(1); % Voltage tolerance system.v_tol = temp(2); elseif strncmpi(keyword,'BUS',3) == 1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % This is a BUS card %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% n_bus = n_bus + 1; % Confirm that a SYSTEM card has preceeded this card if n_system == 0 error (['ERROR: A SYSTEM card must precede any BUS cards!']); end % Get bus name blanks = findstr(data,' '); test = diff(blanks) > 1; for ii = 1:length(test) if test(ii) > 0 bus(n_bus).name = data(blanks(ii)+1:bl