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Sequential AC-DC load flow method for two-terminal HVDC networks

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A HVDC load flow algorithm in Simulink treated separately from an AC load flow in SimPowerSystems.

LF_HVDC_2terminal_INI.m
% File: LF_HVDC_2terminal_INI.m
% By:  Silvano Casoria (Hydro-Quebec, IREQ)
% Version: 1.0
% Description: DC loadflow itialisation data for the "LF_HVDC_2terminal.mdl"
%              model. The model calculates the DC load flow iterative 
%              solution.
% 
Ts_LF = 1;   % Sample time (s) (an arbitrary value)

% Remark : The converter losses attributated to the switching devices
%          not taken into account (are negligible).

% Converter_Rec: ///////////// The Rectifier ////////////////////////
NB_R  = 2;         % Number of 6 pulse bridges
Pn_R  = 600;       % Transformer nominal power (MVA)
V1_R  = 735;       % Primary Nominal (ac side) voltage (kVrms Ph-Ph)
R1_R  = 0.0025;    % Primary winding resistance (pu)
L1_R  = 0.01;      % Primary winding leakage inductance (pu)
V2_R  = 200;       % Secondary (dc side) nominal voltage (kV)
R2_R  = 0.0025;    % Secondary winding resistance (pu)
L2_R  = 0.11;      % Secondary winding leakage inductance (pu)

% ----- Dependent parametres ---------------
% Nominal turn ratio (Usec/Uprim):
TR_R = V2_R/V1_R;

% Transformer reactance seen from secondary, per bridge [XC](ohm):
XC_R = (L1_R+L2_R)*V2_R^2/Pn_R;

% Transformer resistance seen from secondary, per bridge [RC](ohm):
RC_R = (R1_R+R2_R)* V2_R^2/Pn_R; 
% ---------------------

% Converter_INV:   The Inverter
NB_I  = 2;         % Number of 6 pulse bridges
Pn_I  = 600;       % Transformer niminal power (MVA)
V1_I  = 735;       % Primary Nominal (ac side) voltage (kVrms Ph-Ph)
R1_I  = 0.0025;    % Primary winding resistance (pu)
L1_I  = 0.01;      % Primary winding leakage inductance (pu)
V2_I  = 200;       % Secondary (dc side) Nominal voltage (kV)
R2_I  = 0.0025;     % Secondary winding resistance (pu)
L2_I  = 0.11;      % Secondary winding leakage inductance (pu)

% ----- Dependent parametres ---------------
% Nominal turn ratio (Usec/Uprim):
TR_I = V2_I/V1_I;

% Transformer reactance seen from secondary, per bridge [XC](ohm):
XC_I = (L1_I+L2_I)*V2_I^2/Pn_I;

% Transformer resistance seen from secondary, per bridge [RC](ohm):
RC_I = (R1_I+R2_I)* V2_I^2/Pn_I;
% ---------------------

% DC_network_2term: +++++++++++++++++++++++++++++++++++++
RDC    =   12.0+2*0.3;  % (ohm), DC network resistance 
                        % (ex: 800 km line + 2 smoothing reactors)

% Conv_control_Rec :  The Rectifier control
AMODE_ANGLE  =  5.0;    % (deg) Minimum delay (alpha) angle 

% Conv_control_Inv :   The inverter control
GC            =  0;      % (1/0)   1: In Gamma control mode
                         %         0: In Voltage control mode
VSCHED        =  500.0;  % (kV) The regulated DC voltage.
GMODE_ANGLE   =  17.0;   % (deg)  Minimum Gamma angle 
GAMMA_REF     =  22;     % Controled Gamma angle (Used if GC = 1) 

RCOMP         =  0.3;    % (ohm) Compensating resistance for voltage
                         % regulation (ex.: resistance between the voltage
                         % measuring device and the converter terminal)

% Master_control_2term : ***( Master Control )*************************
MDC      = 1;      % Control mode: 0 = blocked
                   %               1 = power control mode
                   %               2 = current control mode
                   
SLACK_ST = 1;      % Loss compensation  station : 1 = Rectifier
                   %                              2 = Inverter
                   
SETVAL =  1000;   % Power or current order (MW or kA), dependig on MDC
                
                   
DELTI  =  0.2;   % (kA) Current margin
                   
if (MDC ==2)
    SETVAL = 2.0; % (kA)
end
               
VCMODE =  VSCHED * 0.94; %(kV)Minimum inverter DC voltage in power control. 

% -------------------  TCC_Rec : Tap Chancher Control at the rectifier ----
LOCK_TAP_R      = 0;   % (1/0) 1: Locks the Tap position
TCC_UDI0_MODE_R = 0;   % (1/0) 1: UDI0 control mode

Udi0_ref_R = 270;      % (kV). 
TAPINI_R   = 1.0;      % Initial Tap (pu)
TAPMN_R    = 0.9375;   % Minimum range  (pu)
TAPMX_R    = 1.125;    % Maximum range (pu)
TSTP_R     = 0.0125;   % Step voltage (pu)
ALFMIN_R   = 14.0;     % Minimum (deg)
ALFMAX_R   = 17.0;     % Maximum (deg)

% ------------------- TCC_Inv : Tap Chancher Control at the inverter-----
LOCK_TAP_I      = 0;   % (1/0)
TCC_UDI0_MODE_I = 0; 

Udi0_ref_I = 270;      % (kV)
TAPINI_I   = 1.0;      % (pu)
TAPMN_I    = 0.9125;  
TAPMX_I    = 1.0875;
TSTP_I     = 0.0125;  
GAMMIN_I   = 20.0;     % (deg)
GAMMAX_I   = 23.0;     
DCVMIN_I   = VSCHED * (1 - TSTP_I);     %(kV)
DCVMAX_I   = VSCHED * (1 + TSTP_I);     
% =====================  E N D ===============================

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