www.lisep.ing.unibo.it

Outline

Interface between the LIOV (Ligthning Induced Overvoltage) code and the EMTP-RV

- Brief review on the functions of the LIOV code

- Explanation of the interface method

- Description of the code used to build the EMTP-rv dynamic-link library

- Couple of examples (one conductor and three conductors)

Scripts for the calculation of voltage profile and short circuit currents in distribution

networks with embedded generation using EMTP-RV

- Scripts for the exchange of data and results between EMTP-rv and Excel.

- Scripts for the repetition of load flow and steady state calculations.

Brief review of the LIOV codeThe LIOV (Lightning-Induced OverVoltage) code is a computer program developed in the

framework of an international collaboration involving the Universities of Bologna

(Department of Electrical Engineering), the Swiss Federal Institute of Technology (Power

Systems Laboratory), and the University of Rome "La Sapienza" (Department of Electrical

Engineering).

The LIOV code allows for the calculation of lightning-induced voltages along an overhead

line as a function of lightning current waveshape (amplitude, front steepness, duration),

return-stroke velocity, line geometry (height, length, number and position of conductors

8), stroke location with respect to the line, ground resisitivity and relative perimittivity,

and value of termination impedances.

The LIOV code is composed by two parts

1) the calculation of the electromagnetic field radiated by the lightning channel that

interacts with the conductors of the overhead line;

2) FTFD solution of the field-to-overhead line coupling equations.

C.A. Nucci, F. Rachidi, “Lightning protection of medium voltage lines”, Chapter 13 of

"Lightning Protection", IEE Power and Energy series 58, IEE Press, London, 2010.

Coupling model

Field-to-transmission line coupling model for a lossless

single conductor overhead line

),,(),(

'),(

thxEt

txiL

x

txv ex

s

=∂

∂+∂

∂

0),(

'),( =

∂∂+

∂∂

t

txvC

x

txi s

∫−=+=ih

ez

si

ei

sii dztzxEtxvtxvtxvtxv

0

),,(),(),(),(),(

1. A.K. Agrawal, H.J. Price, S.H. Gurbaxani, "Transient response of a multiconductor

transmission line excited by a nonuniform electromagnetic field", IEEE Trans. on

Electromagnetic Compatibility, Vol. EMC-22, No. 2, pp. 119-129, May 1980.

FDTD solution of the coupling model

∆−+−

∆−∆−

∆−∆−= −+−+−++

21111

2111 2

2''22' x

vvv

x

EhEh

CL

t

x

ii

C

tvv

nk

nk

nk

nk

nk

nk

nkn

knk

∆−+

∆−+∆+

−

∆−∆−=

−+−+−++

t

EhEhC

x

iii

CL

tEh

x

vv

L

tii

nk

nk

nk

nk

nkn

k

nk

nkn

knk 2

'2

''22'

11

211

2111

n n i v 0 0 , n k

n k i v max max ,

n k

n k i v ,

R 0

∫ h

e z dz t E

0 ) , 0 , 0 ( ∫

h e z dz t L E

0 ) , 0 , (

R L

) t , h , x ( E e x

n+1

n

n - 1

k k+1 k - 1 spatial discretization

time discretization

n-port (EMTP-RV)

LIOV-lines

LIOV-EMTP interface structure

( ) ∫+Γ−=h

ez

n dztEiv0

000 ),0,0(

( ) ∫+Γ=h

ezkk

nk dztLEiv

0

max ),0,(maxmax

Scattered

voltages

Boundary conditionsThe spatial numerical discretization at the two line terminations

(x=0 and x=L) is replaced by means of two Bergeron lines suitably

extended to take into account the presence of the exciting LEMP.

∫∆

−∆−∆−∆−∆=−tu

ex

ss dxthxEtttuZitttuvtZitv0

),,(),(),(),0(),0(

∫∆−

+∆−∆−+∆−∆−=+L

tuL

ex

ss dxthxEtttuLZitttuLvtLZitLv ),,(),(),(),(),(

ut

x =∆∆where

( )nnnnnn EhEhx

ZivZiv 11

0111

01

0 2+∆−−=− +++

( )nk

nk

nk

nk

nk

nk EhEh

xZivZiv 1

111

11

maxmaxmaxmaxmaxmax 2 −+

−−++ +∆++=+

Boundary conditions

( )00 iΓ

( )nn EhEhx

11

02+∆ +

( )hEzn ⋅+10

( )nk

nk EhEh

x1

1

maxmax2 −+ +∆

( )hEznk ⋅+1

max

11

11 , ++ nn iv 1

21

2 , ++ nn iv1

21

2 maxmax, +

−+

−nk

nk iv 1

11

1 maxmax, +

−+

−nk

nk iv

……1

01

0 , ++ nn iv11

maxmax, ++ n

knk iv

( )maxmax kk iΓ

Z Z Z Z

EMTP-RV EMTP-RVLIOV line

0GmaxkG0'G max

'kG

( )nnnnnn EhEhx

ZivZiv 11

0111

01

0 2+∆−−=− +++

( )nk

nk

nk

nk

nk

nk EhEh

xZivZiv 1

111

11

maxmaxmaxmaxmaxmax 2 −+

−−++ +∆++=+

Integration with the augmented nodal analysis

technique implemented in EMTP-RV

The main system of equations in EMTP-RV is given by:

=

v

n

V

n

dr

cn

v

i

i

v

VV

VY

� Yn is the nodal admittance matrix;

� submatrices Vc, Vr and Vd are used to include non-nodal type

equations, such as branch relations (called voltage-defined

equations), but can also use current coefficients;

� vn, iV unknown quantities (nodal voltages and branch currents);

� in current injections and vv voltage-defined equations.

DLL

interface

DLL

interface

Description of the code used to build the EMTP-rv

dynamic-link library

Single_line.ecf

File options.txt

2 fields (1=read, 2=calculate, 3=calculate and write)0 save voltage maximums (0=no, 1=save the extremities max, 2=save the max along the line)1 transient ground resistance (0=no 1=yes)topo.txt topology filename (leave at least a blank character after the filename)1 current (1=Heidler, 2=trapezium)10.7D3,0.25D-6,2.5D-6,2.D0 I01,TAU11,TAU12,NW1 first Heidler6.5D3,2.1D-6,230.D-6,2.D0 I02,TAU21,TAU22,NW2 second Heidler11.2D3,2.D-6 Ip,Tr trapezium4 RS model (1=TL, 2=MTLL, 3=MTLE, 4=TL using analytical formulation)2.D3,1.D-5 LAMBDA (MTLE), linear decay (MTLL)1.3D8 V return stroke speed15 NSIMP (for MTLL and MTLE or numerical TL)8.D3 channel height500,50 X,Y stroke location coordinates1 option minimum delay jump (1=yes)1 option ground (1=lossy, 2=lossless)1.E-2,10. SIGMA,EPSR ground conductivity and permettivity5.D-8,1.D-6 sampling times of Heidler's fuctions in first and second time window1.2 first time window duration / time to peak

File topo.txt

1,1 Number of lines, type of topology file (1 = this one!)

LINEA_1

0,0 X,Y coordinates of the first point of the line (m)

0 angle between the line and the x-axis (degree)

200 length of the line (m)

C:\Programmi\EMTPWorks\Documentation\Help Files\devices\dll\EMTP_dll.pdf

2n power signals

2n voltage sources

0 current sources

0 nonlinear nodes

0 control input signals

0 control output signals

1 means that the file “liov.dll” is in the same folder of the .ecf file

ParamsA

n = number of conductors

MODULE FDTD_DATAUSE sizelimitsUSE default_precisionUSE simulation_dataUSE variableTYPE, PUBLIC :: data_holder

CHARACTER(LEN=max_len_comp_id) :: myname !unique n ame for this device CHARACTER(LEN=40) :: path1INTEGER :: idev !unique d evice number REAL(krealhp), ALLOCATABLE :: Vh(:,:)REAL(krealhp), ALLOCATABLE :: Ih(:,:)REAL(krealhp), ALLOCATABLE :: V(:,:)REAL(krealhp), ALLOCATABLE :: I(:,:)REAL(krealhp), ALLOCATABLE :: DI(:,:,:)REAL(krealhp), ALLOCATABLE :: L(:,:) !line inductanc e matrix pulREAL(krealhp), ALLOCATABLE :: LINV(:,:) !line capaci tance matrix pulREAL(krealhp), ALLOCATABLE :: Z(:,:) !line charact i mpedance matrix[…]

END TYPETYPE(data_holder), POINTER, PUBLIC :: LINE=>NULL()TYPE(data_holder), POINTER, PUBLIC :: LINE_first=>N ULL()LOGICAL, PUBLIC :: EXISTENCE=.FALSE. !indi cates if this device existsLOGICAL, PUBLIC :: EXISTENCE2=.FALSE.[…]

END MODULE

Liov.f90

MODULE FDTD_DATAUSE sizelimitsUSE default_precisionUSE simulation_dataUSE variable

C:\Programmi\EMTPWorks\EMTP\DLL_build\EMTP_Release

SUBROUTINE DLL_INITIALIZE_NEW(myname,idev,Data_Section,DLL_NAME)USE FDTD_DATA!DEC$ ATTRIBUTES DLLEXPORT:: DLL_INITIALIZE_NEWCHARACTER(LEN=*), INTENT(IN) :: myname ! device name in EMTPWorksINTEGER, INTENT(IN) :: idev ! device number in the list of devices of this DLLCHARACTER(LEN=*), INTENT(IN) :: Data_Section(*) !Complete data section of this instanceCHARACTER(LEN=*), INTENT(IN) :: DLL_NAME !the name of this DLL as referenced in EMTPWorksCHARACTER (LEN=100):: drive,dir,name,extIF( EXISTENCE ) THEN !at least one device already exists

ALLOCATE(LINE%next);LINE=>LINE%nextLINE%next=>LINE_first;

ELSEALLOCATE(LINE)LINE_first=>LINE;

ENDIFTotal_number_of_devices=Total_number_of_devices+1;LINE%myname= myname;LINE%idev =idev;

READ(Data_Section(1),*,ERR=999,END=999) LINE%NC[…]END SUBROUTINE DLL_initialize_new

SUBROUTINE DLL_POST_INITIALIZE_NEW(myname,idev,power_signal_no des,n_nodes)

USE FDTD_DATA!DEC$ ATTRIBUTES DLLEXPORT:: DLL_POST_INITIALIZE_NE WCHARACTER(LEN=*), INTENT(IN) :: mynameINTEGER, INTENT(IN) :: idevINTEGER, INTENT(IN) :: power_signal_nodes(*)INTEGER, INTENT(IN) :: n_nodesINTEGER istatLINE=>LINE_first;CALL find_mydev(idev)ALLOCATE(LINE%power_signal_nodes(n_nodes), STAT=ist at);IF(istat.NE.0) CALL device_error_(LINE%myname,'Inte rnal bug.',.TRUE.)LINE%power_signal_nodes=power_signal_nodes(1:n_node s);

END SUBROUTINE DLL_POST_INITIALIZE_NEW

SUBROUTINE DLL_PUT_VOLTAGE_ROW_EQUATIONS(idev,first _voltage_row)USE DFLIBUSE FDTD_DATA!DEC$ ATTRIBUTES DLLEXPORT:: DLL_PUT_VOLTAGE_ROW_EQUATIONSEXTERNAL BIND,BRADREAL(krealhp) :: I_HEID,Imax,IAINTEGER, INTENT(IN) :: idevINTEGER, INTENT(IN) :: first_voltage_rowINTEGER NUM,I,J,K,N,N0,NMAXH,NMAXH1CALL find_mydev(idev)jj=first_voltage_row; !we can increment jj for othe r voltage rowsLINE%first_voltage_row=first_voltage_row;DO k=1,2*LINE%NC

CALL put_(LINE%power_signal_nodes(k),jj+k-1)CALL put_(jj+k-1,LINE%power_signal_nodes(k))

END DOALLOCATE (LINE%L(1:LINE%NC,1:LINE%NC))ALLOCATE (LINE%LINV(1:LINE%NC,1:LINE%NC))ALLOCATE (LINE%Z(1:LINE%NC,1:LINE%NC))ALLOCATE (LINE%DTA2LDXZINV(1:LINE%NC,1:LINE%NC))ALLOCATE (LINE%OTARG(1:LINE%NC,1:2))[…] END SUBROUTINE DLL_PUT_VOLTAGE_ROW_EQUATIONS

Add rows and columns to the EMTP matrix

SUBROUTINE DLL_PUT_IN_YAUG(idev)USE FDTD_DATA

!DEC$ ATTRIBUTES DLLEXPORT:: DLL_PUT_IN_YAUGINTEGER, INTENT(IN) :: idevCALL find_mydev(idev)jj=LINE%first_voltage_row

DO k=1,2*LINE%NCCALL fillreplace_(LINE%power_signal_nodes(k),jj+k-1 ,one)CALL fillreplace_(jj+k-1,LINE%power_signal_nodes(k) ,one)

END DOEND SUBROUTINE DLL_PUT_IN_YAUG

Vs2Vs19Vs1Vs3Is3Is1

Is2Is1900VLVR

=

SUBROUTINE DLL_PUT_IN_IAUG(idev)USE FDTD_DATA!DEC$ ATTRIBUTES DLLEXPORT:: DLL_PUT_IN_IAUGEXTERNAL EXIND,EXRAD,EXSTATEXTERNAL EZIND,EZRAD,EZSTATINTEGER, INTENT(IN) :: idevINTEGER :: jj,kj,K,Jtempo=Simtime%TCALL find_mydev(idev)jj=LINE%first_voltage_rowLINE%ct=LINE%ct+1LINE%Vh=LINE%VLINE%DI(:,0,LINE%ct-1)=LINE%Ih(:,0)LINE%DI(:,LINE%KMAX,LINE%ct-1)=LINE%Ih(:,LINE%KMAX)LINE%Ih=LINE%ILINE%EH3=LINE%EH2LINE%EH2=LINE%EH1LINE%EVh=LINE%EVIF (opzionecampi.EQ.1) THEN[…]DO kj=1,LINE%NC

SimData%vector_b(jj)=LINE%OTARG(kj,1)jj=jj+1SimData%vector_b(jj)=LINE%OTARG(kj,2)jj=jj+1

END DOEND SUBROUTINE DLL_PUT_IN_IAUG

!*Integration using Trapezoidal methodSUBROUTINE DLL_UPDATE_AT_T(idev)USE FDTD_DATAuse numerical_libraries!DEC$ ATTRIBUTES DLLEXPORT:: DLL_UPDATE_AT_TINTEGER, INTENT(IN) :: idevtime=Simtime%TCALL find_mydev(idev)jj=LINE%first_voltage_rowDO kj=1,LINE%NC

LINE%I(kj,0)=SimData%vector_x(jj)jj=jj+1LINE%I(kj,LINE%KMAX)=-SimData%vector_x(jj)jj=jj+1

END DO[…]DO k=1,LINE%KMAX-1

LINE%V(:,k)=1.5E8*MATMUL(LINE%L,(LINE%Ih(:,k-1)-LIN E%Ih(:,k+1)))&+(LINE%Vh(:,k+1)+LINE%Vh(:,k-1))/2&+LINE%deltax*(LINE%EH2(:,k-1)-LINE%EH2(:,k+1))/4

[…]END DO[…]END SUBROUTINE DLL_UPDATE_AT_T

Values of the currents from EMTP

Vector_x

SUBROUTINE DLL_END(idev)USE FDTD_DATA!DEC$ ATTRIBUTES DLLEXPORT :: DLL_ENDINTEGER, INTENT(IN) :: idevCALL find_mydev(idev)

[…]open(1,file=TRIM(cur_path)//'massimo.dat',ACCESS='A PPEND')

WRITE(1,'(D13.7,1X,D13.7,1X,F4.0,1X,F3.0,1X,F3.0)') MAXIMUMclose (1)

[…]

END SUBROUTINE DLL_END

1 – “Load Data & Report”

2 – “Check Line and bus”

3 – “short circuit”

3 sections:

Scripts for DG impact analysis

Node search

parseScriptFile('make_file_name.dwj'); //always nee ded

cct=currentCircuit()nodeNames = cct.signals();writeln(nodeNames) ;var output_file = make_Newfile_name ('_nodi_rete.xls');fid = SPFile(output_file);if(fid.openCreate()){

for(k=0; k<nodeNames.length; k++) { fid.appendLine (nodeNames[k]);}

fid.close() ; }alert('Operazione terminata');

//parseScriptFile('make_file_name.dwj'); //always needed[…]PI_lines=cct.devices('Part','PI'); writeln(PI_lines);[…]for(il=0;il<PI_lines.length;il++){myLine=PI_lines[il];pin_linea=myLine.pins; segnale_sx[il]=myLine.pins[0].signal; segnale_dx[il]=myLine.pins[1].signal; line_type=myLine.getAttribute('ModelData1');line_type=line_type.split(","); //read: [0] line type, [1] cond type; [2] line lengthline_arerea_cavo[il]=line_type[0];line_code[il]=line_type[1];line_length[il]=parseFloat(line_type[2]);

excel_filename=prompt("Nome file Excel:","datiRete.xls");

var Excel;Excel = new ActiveXObject("Excel.Application");Excel.Visible = false;cartExcel = Excel.Workbooks.Open(current_dir+excel_filename);for(k=0; k<PI_lines.length; k++) {

cartExcel.Worksheets("Linee").Cells(k+2,1).Value=PI_lines[k];[…]}cartExcel.SavecartExcel.Close(false);Excel.Quit();Excel = null;alert('Operazione terminata');

PI-line search

//parseScriptFile('make_file_name.dwj'); //always nee ded[…]PQ_loads=cct.devices( 'Part','PQload' );writeln(PQ_loads);PQload_pin=new Array(); for(k=0;k<PQ_loads.length;k++){

myLoad=PQ_loads[k];pin_load=myLoad.pins; PQload_pin[k]=myLoad.pins[0].signal;

}

excel_filename=prompt("Nome file Excel:","datiRete. xls");var Excel;Excel = new ActiveXObject("Excel.Application");Excel.Visible = false;cartExcel = Excel.Workbooks.Open(current_dir+excel_ filename);for(k=0; k<PQ_loads.length; k++) {

cartExcel.Worksheets("Carichi").Cells(k+2,1).Value= PQ_loads[k];cartExcel.Worksheets("Carichi").Cells(k+2,2).Value= PQload_pin[k];

}

cartExcel.SavecartExcel.Close(false);Excel.Quit();Excel = null;alert('Operazione terminata');

PQ-load search

parseScriptFile('make_file_name.dwj'); […]PI_lines=cct.devices( 'Part','PI' ); […]excel_filename=prompt("Nome file Excel:","datiRete. xls");

if( excel_filename==null )//cancel{

writeln('...caricamento dati linee è stato sospeso. ')halt();

} var Excel;Excel = new ActiveXObject("Excel.Application");Excel.Visible = false;cartExcel = Excel.Workbooks.Open(current_dir+excel_ filename);noCod=0;for(i=0;i<PI_lines.length;i++)// scansiona tutte le linee{linea_non_codificata=true;myLine=PI_lines[i];line_type=myLine.getAttribute('ModelData1');

line_type=line_type.split(","); line_length=parseFl oat(line_type[2]); var k=0; if(line_type[0]=='aerea')// if ciclo linee aeree{

while( cartExcel.Worksheets("Tipologia aeree").Cells(4*k+2 ,1).Value!=null ){

line_type_data=String(cartExcel.Worksheets("Tipolog ia aeree").Cells(4*k+2,3).Value) ;if(line_type[1]==line_type_data){

linea_non_codificata=false;R11=cartExcel.Worksheets("Tipologia aeree").Cells(4 *k+2,4).Value*line_length;R12=cartExcel.Worksheets("Tipologia aeree").Cells(4 *k+2,5).Value*line_length;

[…]data_line=R11+' '+R12+' '+R13+'\n'+R21+' '+R22+' '+ R23+'\n'+R31+' '+R32+' '+R33+'\n';[…]myLine.setAttribute('ModelData',data_line);myLine.setAttribute('ParamsA','3,1,0,1Ohm,0,1S,0,1, 1,1,1,')myLine.setAttribute('Category',portataAerea);myLine.fillColor=11; //white

[…]

Load line parameters

parseScriptFile('check_my_filename.dwj');parseScriptFile('make_file_name.dwj'); //always nee dedparseScriptFile('program_.dwj'); //always nee dedparseScriptFile('run_emtp.dwj'); //always nee ded prepare_design_folder(); //always nee dedcurrentCircuit.save();

//Generate the Netlist for the first simulation, ju st in case the netlist does not existstr=runExportToString('report scripts/EMTP Netlist. rfm',null,'NETLIST'); var netlist_file = Netlist_file_name(); //the file must exist

cct=currentCircuit(); current_dir=cct.fileDir;name_cct=cct.fileName;

// add connections OPEN and slack lib=DWLibrary('Pseudo Devices.clf');newType=lib.loadType('Node connector 3-phase');cct.addDevice(newType,-16000,-5000); //add a connec tioncct.addDevice(newType,-15000,-5000); //add a connec tionconnessioni=cct.devices('Part','Pjump3'); // find d evices Pjump3connessioni[0].setAttribute('Name','OPEN',1);connessioni[1].setAttribute('Name','slack',1);segnale_sx=new Array(); // signal sx of Pjump3segnale_dx=new Array(); // signal dx of Pjump3for(il=0;il<connessioni.length;il++){

myConn=connessioni[il];myConn.makeUnique(true); //nomeConn='Connessione '+il;//myConn.setAttribute('Name',nomeConn);

pin_connessione=myConn.pins; segnale_sx[il]=myConn.pins[0].signal; segnale_dx[il]=myConn.pins[1].signal;

if(connessioni[il]=='OPEN') {segnale_dx[il].setAttribute('Name','OPEN',1);}else if (connessioni[il]=='slack') {segnale_dx[il].setAttribute('Name','slack',1);}}

Short-curcuit

AllNodes=cct.signals();sizeAllNodes=AllNodes.length;listaNodiCC=new Arrayexcel_filename=prompt("Nome file Excel:","datiRete. xls"); [...]// auxiliary bussesipg=0;//rappresenta i punti di guasto

for(i=0;i<sizeAllNodes;i++){ if(AllNodes[i]=='Guasto')

{ NodoCC=AllNodes[i]; }else if(AllNodes[i]=='OPEN')

{ NodoOpen=AllNodes[i];}else if(AllNodes[i]=='slack')

{NodoSlack=AllNodes[i]; }else

{ var ii=1;while (cartExcel.Worksheets("CC").Cells(ii+1,1).Val ue!=null)

{if (AllNodes[i]==cartExcel.Worksheets("CC").Cells(i i+1,1).Value)

{listaNodiCC[ipg]=AllNodes[i];ipg=ipg+1;}

ii++;}if(ii==1)

[…]}

}

//----------------------start calculation---------- ---------------------[…]for(i=0;i<listaNodiCC.length;i++)

{[…]

listaNodiCC[i].setAttributeVis('Name',true);listaNodiCC[i].color=1;memoNomePuntoCC=listaNodiCC[i].name;listaNodiCC[i].connectByName(NodoOpen);NodoCC.connectByName(listaNodiCC[i]);runExportToString('report scripts/EMTP Netlist.rfm' ,null,'NETLIST');run_emtp(netlist_file,false); // run---> in "Steady-State"

[...]NodoOpen.connectByName(listaNodiCC[i]);NodoSlack.connectByName(NodoOpen);listaNodiCC[i].color=0;

} // fine ciclo nodi di guasto

writeln(simuRecAllPI_Icc)

//----------------->> end

//------------original solution Steady-state

runExportToString('report scripts/EMTP Netlist.rfm' ,null,'NETLIST');run_emtp(netlist_file,false);

[...]

// rimuovo le connessioni aggiunteconnessioni[0].remove();connessioni[1].remove();

//cartExcel.Close(false);//Excel.Quit();Excel = null;