Comparison of Hardware Tests with SIMULINK Models of UW Microgrid

Transcription

1 Comparion of Hardware Tet with SIMULINK Model of UW Microgrid Introduction Thi report include a detailed dicuion of the microource available on the Univerity- of- Wiconin microgrid. Thi include detail of the SIMULINK model and their comparion with actual dynamic tet. Critical model parameter are alo provided. The microource include inverter baed ource, AC torage and a field wound ynchronou generator. The appendix include SIMULINK model and the network parameter for the network tudie in Phae VIII. Note there i a ignificant difference in the ytem preented at the tart of thi project. The load are different repreenting the actual load available in at Wiconin. Current UW Microgrid Parameter Thi ection document the current actual microgrid circuit ued a Univerity of Wiconin. Thi include line impedance and tranformer data. Thi i the ytem for providing the hardware tet data of the ytem dynamic. Figure 1 how the UW Microgrid diagram. Grid (4.16 kv) Static Switch T 1 Power Cable T 2 Power Cable Power Cable n PC1 n n SS PC 2 UPC 1 PC kv / 0.48 kv 0.48 kv / kv R 1 ES Reitive Load Bank Power Cable Power Cable PC5 PC4 UPC 3 UPC 2 Power Cable Synchroniation Circuit SW R 3 IC SM R 2 MS Reitive Load Bank GENSET PC6 SC Reitive Load Bank Figure 1. Three Phae Diagram of UW Microgrid 1

2 Impedance of microgrid line and tranformer are lited in Table 1 and 2 repectively. Table 1. Line impedance of UW microgrid Line Impedance Length [ft] R [Ω] X L [Ω] X C [Ω] PC PC PC PC PC PC Table 2. Tranformer impedance of UW microgrid Tag Volt- Amp Rating Impedance HV Side Reitance[Ω] HV Side Reactance[Ω] LV Side Reitance[Ω] LV Side Reactance[Ω] T kva 5.50% T 2 75 kva 4.40% T 3 45 kva 4.20% T 4 45 kva 4.20% T 5 45 kva 4.20% Inverter Microource Detail Microource (MS) i illutrated in Figure 2. MS I a, I c Ideal Source V ab,v cb m L F3 L t3 PC 3 T 5 UPC 3 Controller!(t) Inverter Firing Sytem!" V DC CK MS Inverter n 0.48 kv / kv C F3 Figure 2. MS component Inverter voltage and current have a fundamental component and higher harmonic due to the turn- on/off effect of the witche. Harmonic are ignificantly eliminated by mean of LC filter and the 10kHz witching frequency. The inverter i repreented from the microgrid point of view a an ideal, balanced voltage ource with only fundamental component. The output of the inverter i modeled a a controlled voltage ource a hown in Figure 3. 2

3 Ideal Source PC 3 m U ab U ca!(t) U bc Figure 3. Ideal ource model Intantaneou voltage of the controlled voltage ource can be written a following; The quantitie m and θ(t) are the output of the control block. The quantity m i a modulating index, a calar coefficient that when i multiplied by the DC voltage yield the magnitude of the deired voltage at the inverter terminal. The quantity θ(t) i the deired intantaneou value of angle for the voltage at the inverter terminal. Control quantitie ued in thi model are voltage (V mea ), real power (P mea ) and reactive power (Q mea ). Detail of the controller i hown in Figure 4. 3

4 PI V req m K vp K vi - - V ab,v cb I a,i c Calculation of Control Quantitie from Meaurement Voltage (V) Real Power (P) Reactive Power (Q) V * Q * P * F I L T E R S V mea Q mea P mea m Q S BASE! bae V BASE "(t) 1 m P - P req PI P max - K pi K pp - #! 0 P mea PI P min - K pi #! K pp 0 Figure 4. Detailed MS controller cheme, CK MS Real and reactive power (in pu) injected from MS and terminal voltage (in pu) are calculated by ignal proceing block illutrated in Figure 5. V bae V ab-cb ' fd$ 2 ' 1 % " = % & fq# 3 & 0-1/2 $! 3 / 2 " # ' f % & f ab cb $ " # V dq 2 V d V q 2. V* 3 2 ( V qi d! V di q ). Q* I a-c ' fd $ 2 ' 3/2 % " = % & fq# 3 &! 3/ 2 0 $ ' fa $! 3 " % " # & fc # I dq 3 2 ( V d I d V qi q ). P* S bae Figure 5. Control quantitie calculation block 4

5 Intantaneou P, Q and V are calculated uing the rotating d- q reference frame. Intantaneou voltage (current) magnitude i calculated by obtaining the in- phae (direct) and out of phae (quadrature) voltage (current) with repect to phae- a. The calculated V, P and Q quantitie are paed through the low pa filter to attenuate the high frequency component which occur at tep load or power change. Filter diagram i hown in Figure 6. V * 1 1! VQP V mea Q * 1 1! VQP Q mea P * 1 1! VQP P mea Figure 6. Filter diagram Experimental v. Simulation Reult for MS Experimental etup in which MS i iland mode and grid- connected mode i hown in Figure 7. MS parameter are lited in Table 3. Figure 7. Experimental etup diagram for MS 5

6 Table 3. MS parameter V DC S BASE V BASE ω bae Δω P max P min P req V req K pp 3 K pi 30 K vp 0.01 K vi 5 m Q 0.05 m P τ VQP V 15 kva 208 V (2π60) (2π0.5) 15 kw (1 pu) 0 kw 4 kw ( pu) 208 V (1 pu) In thi ilanded cae tudy the inverter ha two reitive load. R2=10.8Ω R3=22.2Ω Initially the load R3 i upplied by the inverter. R2 i witched in at t ec and out at t Reult of imulation and experiment are hown in Figure 8 through 11. Figure 8. Real and reactive power variation of MS 6

7 Figure 9. Frequency variation of MS Figure 10. Voltage variation of MS during load tep up Figure 11. Current variation of MS during load tep up 7

8 Energy Storage, ES, Detail Energy torage (ES) modeling detail are illutrated in Figure 12. ES i alo modeled a a controlled voltage ource. ES Ia, Ic Ideal Source Vab,V cb Controller m!(t) Inverter Firing Sytem!" VDC L F1 PC 1 Lt1 T3 UPC1 CK ES Inverter n 0.48 kv / kv CF1 Figure 12. ES component Detailed controller of ES i hown in Figure 13. A hown, the controller i ame a that of MS. However, P min can have negative value which correpond that of battery charging. PI V req m K vp K vi - - V ab,v cb I a,i c Calculation of Control Quantitie from Meaurement Voltage (V) Real Power (P) Reactive Power (Q) V * Q * P * F I L T E R S V mea Q mea P mea m Q S BASE! bae V BASE "(t) 1 m P - P req PI P max - K pi K pp - #! 0 P mea PI P min - K pi #! K pp 0 Figure 13. Detailed ES controller cheme, CK ES 8

9 2.1. Experimental v. Simulation Reult for ES Experimental etup for ES i illutrated in Figure 14. ES parameter are lited in Table 4. Table 4. ES parameter V DC S BASE V BASE ω bae Δω P max P min P req V req K pp 3 K pi 30 K vp 0.01 K vi 5 m Q 0.05 m P τ VQP 0.01 Figure 14. Experimental etup diagram for ES 750 V 15 kva 208 V (2π60) (2π0.5) 15 kw (1 pu) -2.5 kw ( pu) 4 kw ( pu) 208 V (1 pu) 9

10 In thi cae tudy, the ES inverter upplie the two reitive load in ilanding mode. The load value are fallowing: R1=20.5Ω R2=10.8Ω Initially the load R1 i upplied by the ES inverter. R2 witched in at t ec and out at t , repectively. Reult of imulation and experiment are hown in Figure 15 through 18. Figure 15. Real and reactive power variation of ES Figure 16. Frequency variation of ES 10

11 Figure 17. Voltage variation of ES during load tep up Figure 18. Current variation of ES during load tep up 11

12 GENSET Detail The GENSET block i hown in Figure 19. It comprie of an internal combution (IC) engine driven and a 12.5 KW Kohler field wound ynchronou generator. GENSET I a, I c V ab,v cb E cmd T 4 UPC 2 CK G Controller IC Engine Exciter F cmd! mea PS G n 0.24 kv / kv C G Figure 19. GENSET component Internal combution (IC) engine i illutrated in Figure 20. The exciter model i hown in Figure 21. _ 2 mea K m -" F cmd! K F thr ev K fv cmd e N m _ mea S bae N m - P mec Time Delay Limiter 1 Figure 20. IC Engine model E cmd E cmd _ mea 1 1! e E f Limiter 2 Exciter Machine Figure 21. Exciter model Control quantitie ued in thi model are voltage (V mea ), real power (P mea ), reactive power (Q mea ) and peed of generator (ω mea ). Detail of the controller i hown in Figure 22. The peed of generator i directly meaured from ynchronou machine meaurement terminal. Therefore a peed oberver model i not needed in thi tudy. 12

13 Voltage Regulator V req Exciter Voltage Command E cmd Controller Gv V err - - m Q V BASE V ab,v cb I a,i c Calculation of Control Quantitie from Meaurement Voltage (V) Real Power (P) Reactive Power (Q) V mea Q mea P mea S BASE Governor! bae Fuel Command F cmd Controller Gg! err - m P - P req PI! mea From Synchronou Generator haft P max - K pi K pp " #! 0 P mea PI P min - K pi #! K pp 0 Figure 22. Detailed GENSET controller cheme, CK G The controller Gv in the voltage regulator block i hown in detail in figure 23. K vi V err K vp E cmd PI 1 Figure 23. Detailed diagram of controller Gv The Gv controller i the um of the PI controller and the feed- forward value. Thi i the expected value required for nominal voltage at the terminal. Thi feed- forward contant allow for quicker initial convergence without the integrator having to wind up. 13

14 The controller Gg in governor block i hown in figure 24. P mea K gi! err K gp T e K tf T e F cmd PI Limiter 3 Figure 24. Detailed diagram of controller Gg The governor controller regulate the rotational peed of the genet primarily by a combination of fuel command calculated from the peed error and the output power that i ued to decouple the loading of the machine. The peed error i fed into a PI controller to modify the torque command. The output of the PI controller i the output power at the terminal of the machine. The limiter before the torque command output (T e ) i ued to avoid unrealitic command during large load tranient. The torque command i tranlated into fuel unit command F cmd. Reult for GENSET Simulation etup for the GENSET in iland mode i illutrated in Figure 25. Figure 25. Simulation etup diagram for GENSET 14

15 ICE parameter and Synchronou generator parameter are lited in Table 5 and 6, repectively. Table 5. GENSET parameter S BASE 12.5 kva η thr 0.47 V BASE 208 V K ev ω bae (2π60) K fv 3600 Δω (2π0.5) τ P max 12.5 kw (1 pu) K m 0.36 P min 0 kw τ e V req 208V (1 pu) K vp 100 K pp 3 K vi 30 K pi 30 K gp 10 m P K gi 20 K tf Table 6. Synchronou generator parameter x d T d x d T d x d T q x q R x q H 0.19 x q p 2 In thi cae tudy, the GENSET ha two reitive load. R2=10.8Ω R3=22.2Ω Initially the load R3 i upplied by the GENSET. R2 i witched in at t 1 =3 ec and out at t 2 = 7, repectively. Reult are hown in Figure 26 through

16 Figure 26. Real and reactive power variation of GENSET Figure 27. Frequency variation of GENSET Figure 28. Voltage variation of GENSET during load tep up 16

17 Figure 29. Current variation of GENSET during load tep up 17

18 Appendix A: SIMULINK data A. Microource MS & Energy Storage ES Figure A1. MS (ES) component a) MS (ES) control and ource model b) Ideal voltage ource model Figure A2. MS (ES) Control and Source 18

19 Figure A3. SIMULINK diagram of MS (ES) controller Figure A4. SIMULINK diagram of meaurement calculation Figure A5. SIMULINK diagram of abc to αβ tranformation Figure A6. SIMULINK diagram of filter 19

20 Figure A7. SIMULINK diagram of Q- V droop controller Figure A8. SIMULINK diagram of voltage control Figure A9. SIMULINK diagram of P- ω droop controller 20

21 B. Genet KG Note: See Figure A4- A5 for PQV_Calc block detail Figure B1. KG component IC Engine Model Governor Model Figure B2. SIMULINK diagram of Engine & Governor 21

22 Exciter Model Voltage Regulator Model Figure B3. SIMULINK diagram of Exciter & Regulator 22

23 Appendix B Mehed Microgrid Figure 1 how the UW Mehed Microgrid diagram for Tak VIII tet. From Outide Line L21 L22 PC1 T1 PC2 Bu- 2 P 4,Q 4 PC4 Bu- 1 SS L11 L12 T 2 Energy Storage (15 kw) PC3 75yd P 3,Q 3 L41 L42 PC5 Kohler Genet (12.5 kw) T4 Bu- 4 Micro-Source Inverter baed PC6 P 6,Q 6 P 5,Q 5 (15 kw) L31 T L32 Bu- 3 Figure 1. Single Phae Diagram of UW Mehed Microgrid Impedance of microgrid line and tranformer are lited in Table 1 and 2 repectively. Table 1. Line impedance of UW mehed microgrid Line Impedance Length [ft] R [Ω] X L [Ω] X C [Ω] PC PC PC PC PC PC

24 Table 2. Tranformer impedance of UW mehed microgrid Tag Volt- Amp Rating Impedance HV Side Reitance[Ω] HV Side Reactance[Ω] LV Side Reitance[Ω] LV Side Reactance[Ω] T kva 5.50% T 2 75 kva 4.40% T 3 45 kva 4.20% T 4 45 kva 4.20% T 5 45 kva 4.20% Table 3. Load of UW mehed microgrid Tag L11-L12 L21-L22 L31-L32 L41-L42 Power Rating 4 kw 4 kw 4 kw 4 kw 24