Function MPReduction does modified Ward reduction to the full system
model given in the MATPOWER case file (mpc) based the external buses
(ExBusOrig)defined by the user.
[mpcreduced,Link,BCIRCr]=MPReduction(mpc,ExBusOrig,Pf_flag)
INPUT DATA:
mpc: struct, includes the full model in MATPOWER case format
ExBusOrig: n*1 vector, include the bus numbers of buses to be
eliminated
Pf_flag: scalar, indicate if dc power flow needed to solve (=1) or not
(=0) in the load redistribution subroutine
OUTPUT DATA:
mpcreduced: struct, includes the reduced model in MATPOWER case format
Link: n*2 matrix, includes the generator mapping info, showing how
external generators are moved: The first column includes generator bus
numbers in full model and the second column includes generator bus
nubmers where the external generators are moved to.
BCIRCr: n*1 vector, includes branch circuit numbers. This vector can be
used to identify parallel branches and equivalent lines generated by
the network reduction process. If a branch number is higher than 1 and
less then it indicate this branch is parallel to one of the branch in
the full model. If a branch circuit number is 99 then it indicate this
branch is an equivalent branch.
Note: The reduction is based on dc assumption which means all resistance,
reactive power components will be ignored. And the reduced model is only
good for solving dc power flow or dc opf. If the input full model case
file includes dclines, it is assumed that no dc terminal is to be
eliminated, otherwise the function will return error. If Pf_flag = 1
which means dc power flow need to be solved during the load
redistribution process, user must make sure that MATPOWER toolbox is
installed.0001 function [mpcreduced,Link,BCIRCr]=MPReduction(mpc,ExBusOrig,Pf_flag) 0002 % Function MPReduction does modified Ward reduction to the full system 0003 % model given in the MATPOWER case file (mpc) based the external buses 0004 % (ExBusOrig)defined by the user. 0005 % 0006 % [mpcreduced,Link,BCIRCr]=MPReduction(mpc,ExBusOrig,Pf_flag) 0007 % 0008 % INPUT DATA: 0009 % mpc: struct, includes the full model in MATPOWER case format 0010 % ExBusOrig: n*1 vector, include the bus numbers of buses to be 0011 % eliminated 0012 % Pf_flag: scalar, indicate if dc power flow needed to solve (=1) or not 0013 % (=0) in the load redistribution subroutine 0014 % 0015 % OUTPUT DATA: 0016 % mpcreduced: struct, includes the reduced model in MATPOWER case format 0017 % Link: n*2 matrix, includes the generator mapping info, showing how 0018 % external generators are moved: The first column includes generator bus 0019 % numbers in full model and the second column includes generator bus 0020 % nubmers where the external generators are moved to. 0021 % BCIRCr: n*1 vector, includes branch circuit numbers. This vector can be 0022 % used to identify parallel branches and equivalent lines generated by 0023 % the network reduction process. If a branch number is higher than 1 and 0024 % less then it indicate this branch is parallel to one of the branch in 0025 % the full model. If a branch circuit number is 99 then it indicate this 0026 % branch is an equivalent branch. 0027 % 0028 % Note: The reduction is based on dc assumption which means all resistance, 0029 % reactive power components will be ignored. And the reduced model is only 0030 % good for solving dc power flow or dc opf. If the input full model case 0031 % file includes dclines, it is assumed that no dc terminal is to be 0032 % eliminated, otherwise the function will return error. If Pf_flag = 1 0033 % which means dc power flow need to be solved during the load 0034 % redistribution process, user must make sure that MATPOWER toolbox is 0035 % installed. 0036 0037 % MATPOWER 0038 % Copyright (c) 2014-2015 by Power System Engineering Research Center (PSERC) 0039 % by Yujia Zhu, PSERC ASU 0040 % 0041 % $Id: MPReduction.m 2655 2015-03-18 16:40:32Z ray $ 0042 % 0043 % This file is part of MATPOWER. 0044 % Covered by the 3-clause BSD License (see LICENSE file for details). 0045 % See http://www.pserc.cornell.edu/matpower/ for more info. 0046 0047 fprintf('%n Reduction process start'); 0048 fprintf('%n Preprocess data')'; 0049 [mpc,ExBusOrig]=PreProcessData(mpc,ExBusOrig); 0050 dim = size(mpc.bus,1); 0051 %% Modeling 0052 % check if dc terminals are external 0053 if isfield(mpc,'dcline') 0054 tf1 = ismember(mpc.dcline(:,1),ExBusOrig); 0055 tf2 = ismember(mpc.dcline(:,2),ExBusOrig); 0056 if (sum(tf1)+sum(tf2))>0 0057 error('not able to eliminate HVDC line terminals'); 0058 end 0059 end 0060 ExBusOrig = ExBusOrig'; 0061 if ~isempty(ExBusOrig) 0062 fprintf('\nConvert input data model'); 0063 [NFROM,NTO,BraNum,LineB,ShuntB,BCIRC,BusNum,NUMB,SelfB,mpc,ExBus,newbusnum,oldbusnum] = Initiation(mpc,ExBusOrig); % ExBus with internal numbering 0064 %% Create data structure 0065 fprintf('\nCreating Y matrix of input full model'); 0066 [CIndx,ERP,DataB]=BuildYMat(NFROM,NTO,BraNum,LineB,BCIRC,BusNum,NUMB,SelfB); 0067 %% Do Reduction 0068 fprintf('\nDo first round reduction eliminating all external buses'); 0069 [mpcreduced,BCIRCr,ExBusr] = DoReduction(DataB,ERP,CIndx,ExBus,NUMB,dim,BCIRC,newbusnum,oldbusnum,mpc); % ExBusr with original numbering 0070 %% Generate the second reduction with all retained buses and all generator 0071 %% buses mpcreduced_gen 0072 % Create the ExBus_Gen to create the reduced model with all gens 0073 tf = ismember(ExBus,mpc.gen(:,1)); 0074 ExBusGen = ExBus; 0075 ExBusGen(tf==1)=[]; % delete all external buses with generators 0076 tf=ismember(mpc.gen(:,1),ExBus); 0077 fprintf('\n%d external generators are to be placed',length(tf(tf==1))); 0078 if ~isempty(ExBusGen) 0079 fprintf('\nDo second round reduction eliminating all external non-generator buses'); 0080 [mpcreduced_gen,BCIRC_gen,ExBusGen] = DoReduction(DataB,ERP,CIndx,ExBusGen,NUMB,dim,BCIRC,newbusnum,oldbusnum,mpc); 0081 else 0082 mpcreduced_gen = mpc; 0083 mpcreduced_gen=MapBus(mpcreduced_gen,newbusnum,oldbusnum); 0084 BCIRC_gen = BCIRC; 0085 end 0086 %% Move Generators 0087 fprintf('\nPlacing External generators'); 0088 [NewGenBus,Link]=MoveExGen(mpcreduced_gen,ExBusOrig,ExBusGen,BCIRC_gen,0); 0089 mpcreduced.gen(:,1)=NewGenBus; % move all external generators 0090 %% Do Inverse PowerFlow 0091 fprintf('\nRedistribute loads'); 0092 mpc=MapBus(mpc,newbusnum,oldbusnum); 0093 [mpcreduced,BCIRCr]=LoadRedistribution(mpc,mpcreduced,BCIRCr,Pf_flag); 0094 else 0095 mpcreduced = mpc; 0096 warning('No external buses, reduced model is same as full model'); 0097 end 0098 %% Delete large reactance equivalent branches 0099 ind=find(abs(mpcreduced.branch(:,4))>=max(mpc.branch(:,4))*10); 0100 mpcreduced.branch(ind,:)=[]; 0101 BCIRCr(ind)=[]; 0102 %% Print Results 0103 fprintf('\n**********Reduction Summary****************'); 0104 fprintf('\n%d buses in reduced model',size(mpcreduced.bus,1)); 0105 fprintf('\n%d branches in reduced model, including %d equivalent lines',size(mpcreduced.branch,1),length(BCIRCr(BCIRCr==max(BCIRCr)))); 0106 fprintf('\n%d generators in reduced model',size(mpcreduced.gen,1)); 0107 if isfield(mpcreduced,'dcline') 0108 fprintf('\n%d HVDC lines in reduced mode,',size(mpcreduced.dcline,1)); 0109 end 0110 fprintf('\n**********Generator Placement Results**************'); 0111 for i=1:size(Link,1) 0112 if Link(i,2)-Link(i,1)~=0 0113 fprintf('\nExternal generator on bus %d is moved to %d',Link(i,1),Link(i,2)); 0114 end 0115 end 0116 fprintf('\n'); 0117 0118 end