Extracting Symmetrical Components Data from ATP and EMTDC Line Constants Program Results

Transcription

1 Session 3; Page /3 Spring 8 Extracting Symmetrical Components Data from ATP and EMTDC Line Constants Program Results Using ATP/ATPDraw (option ) Use Bergeron transmission model from Lecture 3 (with a 6 Hz output frequency). - Run the line constants program within LCC to generator an output file - Note the file name that the line model is saved to. - Two files will be created, one with an extension L3.pch and the other L3.lib - The L3.lib file is the one read by ATP when executing the overall system model

2 Session 3; Page /3 Spring 8 Now close the LCC window (if you made any changes it may rerun the case) Under the ATP pulldown menu of the main program window: - Select View LIS file or press the <F5> key on your keyboard If you have run the ATPDraw case previously a text file will be opened in the editor If you haven't run a case, there won't be an open file Now go to the file menu in the text editor program and chose "Open" Change the file type to "Library files (*.lib)" Select the L3.lib file (choose the file you saved for the line you are modeling

3 Session 3; Page 3/3 Spring 8 Assuming your LCC case ran correctly, you should get the following file if you had an untransposed Bergeron line - The line modal parameters are in the lines starting "-", "-", etc - The modal transformation matrix for the currents, "Ti" starts after the $VINTAGE, - Note since I selected "Real Transformation Matrix" the imaginary parts of Ti are. KARD KARG KBEG KEND KTEX /BRANCH $VINTAGE, -IN AOUT A 3.649E E+.364E+5-.E+ 3 -IN BOUT B E- 4.35E+.9389E+5-.E+ 3-3IN COUT C E E+.939E+5-.E+ 3 $VINTAGE, $EOF ARG, IN A, IN B, IN C, OUT A, OUT B, OUT C From the above (units of length in since units had been selected as Metric): R m ohm R m ohm R m ohm Z m ohm Z m 4.35 ohm Z m ohm ν m ν m ν m sec sec sec Recall that Z m L m = and ν m = C m L m C m Rearranging L m = C m Z m then C m = ν m Lm = ν m Cm Z m

4 Session 3; Page 4/3 Spring 8 or: C m = then: C m = ν m Zm ν m Z m C m ν m Z C m 6.7 nf m L m C m Z m L m mh C m ν m Z C m nf m L m C m Z m L m.484 mh C m ν m Z C m 8.9 nf m L m C m Z m L m.99 mh Current transformation matrix (only show the real part since the imaginary terms are ) T i_untrans I Recall T T e T i = d just let d = T e_untrans T IT i_untrans.5759 T e_untrans

5 Session 3; Page 5/3 Spring 8 As a check T T e_untrans T i_untrans Now we can find the ABC domain matrices for R, L and C per unit length, using equations (8) and (9) from the lecture handout R m R' untran T e_untrans T i_untrans R m R m.678 R' untran ohm L m L' untran T e_untrans T i_untrans L m L m.66 L' untran mh C m C' untran T i_untrans T e_untrans C m C m C' untran nf

6 Session 3; Page 6/3 Spring 8 a e jdeg A a a a a Length ω π6hz Z ABC_untran R' untran jω L' untran Length i Z ABC_untran i i i i i i i i Ω Z _untran A ZABC_untran A i Z _untran i.3.638i.3.638i i i i i i Ω Using ATP/ATPDraw (option ) If all we want are the symmetrical components, and not the ABC matrices we can also select that the line be transposed (using the Bergeron model): Now the Library file from ATPDraw's LCC program gives us - The modal transformation matrix is assumed to be Bergeron now - The modal values are the same as the symmetrical components expressed per unit length KARD KARG KBEG KEND KTEX /BRANCH $VINTAGE, -IN AOUT A 3.646E E+.87E+5.E+ -IN BOUT B 7.76E E+.94E+5.E+ -3IN COUT C $VINTAGE, -, $EOF ARG, IN A, IN B, IN C, OUT A, OUT B, OUT C R b ohm R b 7.76 ohm R b R b

7 Session 3; Page 7/3 Spring 8 Z c ohm Z c ohm Z c Z c ν.87 5 ν.94 5 s s C b ν Z C b 6.3 nf c L b C b Z c L b 3.69 mh C b ν Z C b 8.45 nf c L b C b Z c L b.39 mh Z _trans R b jωl b Length Z _trans ( i)Ω Z _trans R b jωl b Length Z _trans ( i)Ω Compare to earlier result Z _untran Z _untran ( i)Ω ( i)Ω Percent Error Z _untran Z _untran Z _trans.73 % Z _untran Z _untran Z _trans. % Using ATP/ATPDraw (option 3) As a final option, we can select the coupled-pi model instead of the Bergeron line model This gives the impedance matrix (multiplied times the length of the line segment) You don't need to select Matrix Output KARD KARG KBEG KEND

8 Session 3; Page 8/3 Spring 8 KTEX /BRANCH $UNITS, 6.,. $VINTAGE, $UNITS, 6.,., IN AOUT A E E E- IN BOUT B E E E E E E- 3IN COUT C E E E E E E E E E- $VINTAGE, -, $UNITS, -., -., { Restore values that existed b4 preceding $UNITS $UNITS, -., -. $EOF ARG, IN A, IN B, IN C, OUT A, OUT B, OUT C Result is the lower triangular parts of the R, L and C matrix (multiplied times length of the line) Matrix is symmetric R pi ohm Compare to the initial results for the untransposed Bergeron line R' untran Length ohm So there is some noticeable difference. Now look at the inductance matrix (the pi model in ATPDraw gives the result in ohms, not mh X L_pi ohm L' untran Lengthω Ω Again there are differences

9 Session 3; Page 9/3 Spring 8 Z _pi A R pi jx L_pi A i Z _pi i i i Z _untran i.3.638i i i i.3.638i i i i i i i i i Ω Ω Percent Error Z _untran Z _pi Z _untran Z _untran Z _pi Z _untran.74 %.3 % So while the error is visible visually looking at the matrices, the percent error is very small In both cases here it is close to what we observed with the Bergeron line case Error would be even smaller if we had used the full transformation matrix for the untransposed line, instead of just the real part Now look at the capacitance matrix (the pi model in ATPDraw gives the result in uf) C pi μf C pi μf C' untran Length μf Even better match than the series impedance

10 Session 3; Page /3 Spring 8 Using PSCAD/EMTDC Again, use the line modelled in lecture 3 Enter the mode to edit the line constants data Notice the 5 tabs at the bottom of the window above - By default, we are normally in the Editor Choose the one labelled Output Result is a table with various matrix outputs... ===================================================== PSCAD LINE CONSTANTS PROGRAM OUTPUT FILE (*.out) NOTE: This file is auto-generated. Any manual changes will be lost once the Line Constants Program is re-run. ===================================================== Display Format: M,N denotes a complex number M + jn PHASE DOMAIN 6. Hz:

11 Session 3; Page /3 Spring 8 SERIES IMPEDANCE MATRIX (Z) [ohms/m]:.7667e-3,.87359e e-4,.9947e e-4,.9947e e-4,.9947e e-3,.87359e e-4,.9947e e-4,.9947e e-4,.9947e e-3,.87359e-3 SHUNT ADMITTANCE MATRIX (Y) [mhos/m]:.e-,.86466e-8.e+, e-9.e+, e-9.e+, e-9.e-,.86466e-8.e+, e-9.e+, e-9.e+, e-9.e-,.86466e-8 LONG-LINE CORRECTED SERIES IMPEDANCE MATRIX [ohms]: e+,.8467e e+,.993e e+,.993e e+,.993e e+,.8467e e+,.993e e+,.993e e+,.993e e+,.8467e+ LONG-LINE CORRECTED SHUNT ADMITTANCE MATRIX [mhos]: e-5,.86975e e-7,-.9948e e-7,-.9948e e-7,-.9948e e-5,.86975e e-7,-.9948e e-7,-.9948e e-7,-.9948e e-5,.86975e-3 MODAL DOMAIN 6. Hz: YZ EIGENVECTOR (MODAL TRANSFORMATION) MATRIX (TI): E+,.E E+, E E+, E E+, E E+, E E+, E E+, E E+,.E E+,.E+ YZ EIGENVALUE VECTOR:.48857E+, E+.764E+, E E+, E+ MODAL IMPEDANCE MATRIX [ohms/m]:.7967e-4, e-3.e+, e e-4, e-3.e+,.e e-3, e E-8, E E-4, E E-8,.35665E E-3, E-3 MODAL ADMITTANCE MATRIX [mhos/m]: E-9,.356E-8.E+,.E E-9, E-9.E+,.E+.E-, E-8.E+,.E E-9, E-9.E+,.E E-9, E-8 MODAL CHARACTERISTIC IMPEDANCE VECTOR (Z) [ohms]: e+3, e e+3, e e+3, e+ MODAL TRAVEL TIME VECTOR [ms]: e e e+ MODAL VELOCITY VECTOR [m/s]:.933e e+9.933e+9

12 Session 3; Page /3 Spring SEQUENCE COMPONENT 6. Hz: SEQUENCE TRANSFORM MATRIX: E+,.E E+,.E E+,.E E+,.E E+,-.5E E+,.5E E+,.E E+,.5E E+,-.5E+ SEQUENCE IMPEDANCE MATRIX (Zsq) [ohms/m]: e-3, e-.e+,.e+.e+,.e+.e+,.e+.7967e-4, e-3.e+,.e+.847e-8,.e+.e+,.e+.7967e-4, e-3 SEQUENCE ADMITTANCE MATRIX (Ysq) [mhos/m]:.e-, e-8.e+,.e+.e+,.e+.e+,.e+.e-, e-8.e+,.e+.e+,.e+.e+,.e+.e-, e-8 LOAD FLOW RXB FORMATTED 6. Hz: Per-Unit Quantities Based On: Base Voltage: 3. kv,l-l,rms Base MVA:. MVA NOTE: Base values are set using Output File Data Display Options component in Editor view. LONG-LINE CORRECTED SEQUENCE RESISTANCE RLLsq [p.u.]: + Seq. Self: E- Seq. Self: E- LONG-LINE CORRECTED SEQUENCE REACTANCE XLLsq [p.u.]: + Seq. Self: E- Seq. Self: LONG-LINE CORRECTED SEQUENCE SUSCEPTANCE BLLsq [p.u]: + Seq. Self: Seq. Self:.966 SEQUENCE RESISTANCE Rsq [p.u.]: + Seq. Self: E- Seq. Self: E- SEQUENCE REACTANCE Xsq [p.u.]: + Seq. Self: E- Seq. Self:.655 SEQUENCE SUSCEPTANCE Bsq [p.u.]: + Seq. Self: Seq. Self:.9874

13 Session 3; Page 3/3 Spring 8 From the sequence impedance matrix we get: Z _pscad j ohm m Z _pscad Length ( i)Ω Z _pscad j ohm m Z _pscad Length ( i)Ω Comparison of results Z _untran Z _pscad Length.945 % Z _untran Z _untran Z _pscad Length.847 % Z _untran Closer match in the positive seqence than in zero sequence Possible sources of error - PSCAD/EMTDC used the imaginary part of the transformation matrix (but that should not cause this much error - The two programs model the effect of the earth somewhat differently.