calc.m

潮流计算

function [delP,delQ,P,Q,conv_flag] = ...
                 calc(nbus,V,ang,Y,Pg,Qg,Pl,Ql,sw_bno,g_bno,tol)
% Syntax:  [delP,delQ,P,Q,conv_flag] = 
%                calc(nbus,V,ang,Y,Pg,Qg,Pl,Ql,sw_bno,g_bno,tol)
%
% Purpose: calculates power mismatch and checks convergence
%          also determines the values of P and Q based on the 
%          supplied values of voltage magnitude and
%          angle计算功率偏差，检查收敛，根据电压赋值和相角决定有功无功
% Version: 2.0 eliminates do loop
% Input:   nbus      - total number of buses节点数
%          bus_type  - load_bus(3), gen_bus(2), swing_bus(1)节点类型
%          V         - magnitude of bus voltage电压值
%          ang       - angle(rad) of bus voltage电压相角
%          Y         - admittance matrix导纳矩阵
%          Pg        - real power of generation发电机有功
%          Qg        - reactive power  of generation发电机无功
%          Pl        - real power of load负荷有功
%          Ql        - reactive power of load负荷无功
%	       sw_bno    - a vector having zeros at all  swing_bus locations ones otherwise
%                    列矢量平衡节点处为0，其他位置为1
%	       g_bno     - a vector having zeros at all  generator bus locations ones otherwise
%                    列矢量发电机节点处为0，其他位置为1             
%          tol       - a tolerance of computational error精度
%
% Output:  delP      - real power mismatch有功偏差
%          delQ      - reactive power mismatch无功偏差
%          P         - calculated real power计算的有功
%          Q         - calculated reactive power计算的无功
%          conv_flag - 0, converged收敛＝1
%                      1, not yet converged不收敛＝0
%算法：获得当前注入每个节点的电流通过用导纳矩阵左乘节点电压矢量。通过电流和电压可以算出有功和无功功率。
%误差：delP = Pg - Pl - P; delQ = Qg - Ql - Q

% See also:  
%
% Calls:
%
% Called By:   loadflow

% (c) Copyright 1991 Joe H. Chow - All Rights Reserved
%
% History (in reverse chronological order)
% Version:   2.0
% Author:    Graham Rogers
% Date:      July 1994
%
% Version:   1.0
% Author:    Kwok W. Cheung, Joe H. Chow
% Date:      March 1991
%
% ************************************************************
jay = sqrt(-1);
swing_bus = 1;
gen_bus = 2;
load_bus = 3;
% voltage in rectangular coordinate直角坐标下的电压
V_rect = V.*exp(jay*ang);  %电压的向量形式
% bus current injection注入的节点电流
cur_inj = Y*V_rect;%电流=导纳×电压
% power output based on voltages 基于电压的功率输出
S = V_rect.*conj(cur_inj);%视在功率＝电压×电流的共轭
P = real(S); Q = imag(S);
delP = Pg - Pl - P;%节点有功功率偏差
delQ = Qg - Ql - Q;%节点无功功率偏差
% zero out mismatches on swing bus and generation bus不考虑平衡节点的偏差和发电机节点的无功偏差
delP=delP.*sw_bno;%平衡节点处有功偏差＝0
delQ=delQ.*sw_bno;%平衡节点处的无功偏差＝0
delQ=delQ.*g_bno;%发电机节点处的无功偏差＝0
%  total mismatch总偏差
[pmis,ip]=max(abs(delP));%ip是最大有功偏差的位置,pims是列ip中的最大值
[qmis,iq]=max(abs(delQ));%找出最大无功偏差qmin（绝对值）
mism = pmis+qmis;%有功＋无功
%  判断是否收敛
if mism > tol,  %如果超过限制
    conv_flag = 1;%表示不收敛
  else
    conv_flag = 0;
end
return%返回主程序