Control and Design of Microgrid Components - Power Systems ...

More documents

Recommendations

Info

Utility System Event: Transfer to Island F 1 P 1 4 wire 75yd 4 wire 25yd P 2 L L 1 3 L4 L5 Figure 7.2 Series Configuration Diagram. F 2 Maximum power corresponds to 0.8 pu in the source because of the DSP capability of handling only quantities that are in the –1,+1 interval. To leave room for overshoot, the value of P_max has been chosen to correspond to 0.8. After the system transfers to island, unit 2 will be sitting at 100% of power (0.8 pu), while unit 1 will be sitting at 50% (since overall loading is 150%) of power (0.4 pu), in all of the four configurations. What really changes, is how they get there. Figure 7.3 and Figure 7.4 show simulation results when P1 and P2 are controlled: both units ramp up their power output (P) at the unison. Overshoot at unit 2 is near 0.89 pu (110%). Figure 7.5 and Figure 7.6 show that when F1 and F2 are controlled, then as P2 ramps, P1 actually backs off, after rising a little. This means that the resulting overshoot on P2 is about 1.04 pu (130%). This implies tripping of the units, since nearly above 0.9 pu is the threshold value for power, and besides, a value larger than 1.0 is also beyond the overflow value of the bit representation inside the DSP. Figure 7.7 and Figure 7.8 show that when F1 and P2 are controlled, then an unacceptable overshoot also occurs. Figure 7.9 and Figure 7.10 show that when P1 and F2 are controlled, the overshoot is manageable again. This implies that the choice of control configurations bears a consequence on the ratings of the inverters that need to be available, or the gains may need to be readjusted (when possible) to improve response. For this lab case, the above considerations implied that the test for 10% and 90% could not be carried under those cases that generated very large overshoots. To avoid tripping of the units, the setpoint corresponding to loading of respectively 30% and 70% for unit 1 and 2 have been chosen only for the cases with larger overshoot. This problem was only encountered during 10%, 90% setup, never during 90%, 10%, hence this latter configuration has never been changed. Also these problems are only encountered at high load levels (importing to grid). Therefore, during exporting no changes were necessary to 10%, 90% setup. Finally, no problems were encountered during the parallel configuration, so no changes had to be made there as well. The Table 7.2 below summarizes the previous considerations. 94
Table 7.2 Series Configuration Control Combinations. Importing from Grid. Control of Unit 1 Control of Unit 2 Overshoot on Unit 2 P P 0.89 pu ~ 110% F F 1.04 pu ~ 130% F P 1.04 pu ~ 130% P F 0.89 pu ~ 110% Figure 7.3 Control of P1 and P2, Unit Power. 95
Page 1 and 2:
PSERC Control and Design of Microgr
Page 3 and 4:
Information about this project For
Page 5 and 6:
Executive Summary Economic, technol
Page 7 and 8:
Table of Contents Chapter 1. Introd
Page 9 and 10:
List of Figures Figure 1.1 Microgri
Page 11 and 12:
List of Figures (continued) Figure
Page 13 and 14:
Chapter 1. Introduction Distributed
Page 15 and 16:
1.2.2 Operation and Investment The
Page 17 and 18:
Figure 1.1 Microgrid Architecture D
Page 19 and 20:
Chapter 2. Static Switch The static
Page 21 and 22:
ω ωo ω1 Preq Pgrid P Pload Figur
Page 23 and 24:
2.3 Synchronization Conditions The
Page 25 and 26:
droop. The issue is that it is poss
Page 27 and 28:
This synchronizing behavior is unac
Page 29 and 30:
Figure 2.12 shows on the upper plot
Page 31 and 32:
Chapter 3. Microsource Details This
Page 33 and 34:
with different size. This control i
Page 35 and 36:
u + _ K F ω o + _ ω o s P u ω o
Page 37 and 38:
Q versus E Droop E req Q m Q _ + E
Page 39 and 40:
currents from the microsources incr
Page 41 and 42:
inverter ratings limits (in kVA) ca
Page 43 and 44:
A 16 DG B 22 DG Static Switch C 8 D
Page 45 and 46:
ω Unit 2 Max Unit 2 ω o Unit 1 ω
Page 47 and 48:
Unit 1 Min Unit 2 ω Unit 1 ΔPmin
Page 49 and 50:
positive value. When this value has
Page 51 and 52:
needs of power. This solution would
Page 53 and 54:
This expression is very similar to
Page 55 and 56: Li-Pmax < Fi < Li for unit ‘i’
Page 57 and 58: ω ω ω o Fo ω o Fo F F Unit Powe
Page 59 and 60: This control has been implemented i
Page 61 and 62: characteristic will coincide with t
Page 63 and 64: ating on the voltage output, establ
Page 65 and 66: Prime Mover DC Storage Voltage Sour
Page 67 and 68: linearity. A value of 30 degrees pr
Page 69 and 70: Figure 4.8 P and Q Plane Capability
Page 71 and 72: 4.4 System Ratings The inverter per
Page 73 and 74: Switching Sequence 145 146 136 236
Page 75 and 76: generated by the inverter: the VA r
Page 77 and 78: % of voltage unbalance = 100 maximu
Page 79 and 80: Figure 5.2 shows the plots for P,Q
Page 81 and 82: Figure 5.5 shows the measures of P
Page 83 and 84: Figure 5.7 One Unit Connected to th
Page 85 and 86: Microsources are connected to the l
Page 87 and 88: The transformer impedance can be se
Page 89 and 90: o r 1 = 0.3277 Ω = 0.0547 Ω x x 1
Page 91 and 92: Table 6.3 Load Data Summary. Rated
Page 93 and 94: The worse case scenario is represen
Page 95 and 96: The filtering is achieved by a low
Page 97 and 98: works with an internal voltage leve
Page 99 and 100: terminals to achieve each of the th
Page 101 and 102: Table 6.5 Lookup Table for Switchin
Page 103 and 104: Chapter 7. Microgrid Tests There ar
Page 105: Table 7.1 Summary of Experiments fo
Page 109 and 110: Figure 7.6 Control of F1 and F2, Fe
Page 111 and 112: Figure 7.10 Control of P1 and F2, F
Page 113 and 114: pu, but when it is fed from a remot
Page 115 and 116: Unit 1: P, Q, F, Frequency, Voltage
Page 157 and 158:
Unit 1: P, Q, F, Frequency, Voltage
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
7.4.1 Unit 1 (F), Unit 2 (F), Impor
Page 209 and 210:
Import From Grid, Setpoints are 10%
Page 211 and 212:
Page 213 and 214:
Island, Setpoints are 10% and 90% o
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
7.4.2 Unit 1 (F), Unit 2 (F), Expor
Page 223 and 224:
Export to Grid, Setpoints are 10% a
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
7.4.3 Unit 1 (F), Unit 2 (P), Impor
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
7.4.4 Unit 1 (F), Unit 2 (P), Expor
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Chapter 8. Conclusions This work sh
Page 257:
[14] Lasseter, R.,” Microgrids,
show all

Control and Design of Microgrid Components - Power Systems ...

Create successful ePaper yourself

Delete template?

Save as template?