Control, Protection, and Realtime Simulation of Microgrids

Transcription

1 Large-scale Integration of Distributed Energy Resources: Control, Protection, and Realtime Simulation of Microgrids Amir Etemadi US China Smart Grid Workshop May 16, 2014 Nanjing, China Slide 1 of 24

2 Outline Statement of the Problem Proposed Microgrid Control Strategy Sample Case Studies Offline Time-Domain Simulations Hardware-in-the-Loop (HIL) Simulations Conclusions Future Research Directions Slide 2 of 24

3 Statement of the Problem Poor DER Transient Units Response Controller Close Instability Coupling Issues Frequency Fast Dynamics Deviation Limited Lack Configurations of Inertia Intermittency Black-start Microgrid Uncertainty DER DER DER DER IEEE July 2011 DER Slide 3 of 24

4 Outline Statement of the Problem Proposed Microgrid Control Strategy Sample Case Studies Offline Time-Domain Simulations Hardware-in-the-Loop (HIL) Simulations Conclusions Future Research Directions Slide 4 of 24

5 Proposed Strategy Power Management System (PMS) Open-loop Frequency Control and DER Synchronization Local Controllers (LC) Slide 5 of 24

6 Functions of PMS Collecting Microgrid Data Determining Necessary Power and Voltage Set Points to Achieve a Prescribed Load Sharing Communicating Set Points to DER Units P1,Q1 Power Management System V2<δ2 P3,Q3 LC DER LC DER LC DER Slide 6 of 24

7 Frequency Control & Synchronization θ(rad) 2π 1pps θ0 One 60Hz Cycle DER θ(rad) 2π DER θ0 DER One 60Hz Cycle θ(rad) 2π θ0 One 60Hz Cycle Slide 7 of 24

8 Local Controller Functions Tracking the Set Points Rejecting Disturbances Main Features Robust Performance Decentralized Nature Slide 8 of 24

9 Structure of Local Controllers Voltage-controlled units: V d,ref V q,ref Power-controlled units: I d,ref I q,ref Slide 9 of 24

10 Outline Statement of the Problem Proposed Microgrid Control Strategy Sample Case Studies Offline Time-Domain Simulations Hardware-in-the-Loop (HIL) Simulations Conclusions Future Research Directions Slide 10 of 24

11 Studied Microgrid Slide 11 of 24

12 Structure of the Proposed Strategy LC3 System Status via Low Band Communication Power Management System P,Qref,1 Vref,2 P,Qref,3 V3 V2 V1 Controller LC2 Controller LC1 Controller Gating Signals 1 Gating Signals 2 Gating Signals 3 Synchronizing Signal Slide 12 of 24

13 Case Studies Load Disconnection Set Point Update by PMS Overload Protection Set Point Update by PMS Slide 13 of 24

14 Case Studies 2 V P,Q 1 P,Q,S 2 P,Q DG1 DG2 DG3 0 Time Set Overload Load Point Disconnection update Protection by PMS Slide 14 of 24 26

15 Outline Statement of the Problem Proposed Microgrid Control Strategy Sample Case Studies Offline Time-Domain Simulations Hardware-in-the-Loop (HIL) Simulations Conclusions Future Research Directions Slide 15 of 24

16 HIL Simulation Objectives To verify results of offline simulation case studies To demonstrate proposed algorithms are readily implementable in industrial-grade hardware To demonstrate satisfactory performance of the controllers despite hardware implementation issues such as noise, A/D and D/A nonidealities, and delays Slide 16 of 24

17 HIL Block Diagram Power Management System GPC Card Digital Inputs RTDS Analog Outputs V 2 I 3 V1 V2 V3 I 1 PWM1 PWM2 PWM3 A/I D/O A/I D/O A/I D/O NI-cRIO 3 FPGA FPGA CPU NI-cRIO 2 FPGA CPU NI-cRIO 1 CPU D/I LAN D/I LAN D/I LAN Digital Clock for Synchronization Slide 17 of 24

18 HIL Picture Slide 18 of 24

19 Test Case: Induction Motor Starting M M M DG1 DG2 DG3 Slide 19 of 24

20 Outline Statement of the Problem Proposed Microgrid Control Strategy Sample Case Studies Offline Time-Domain Simulations Hardware-in-the-Loop (HIL) Simulations Conclusions Future Research Directions Slide 20 of 24

21 Conclusions Features of the Proposed Strategy Enabling a Prescribed Load Sharing Tracking Set Points/Rejecting Disturbances Systematic Design Approach Highly Robust Performance Decentralized Nature/Modular and Scalable DER Integration/Accommodating Abrupt DER Switching Providing Fixed Frequency DER output current/power Limitation Enabling Different DER Control Modes Minimized Transients of Control Switching Slide 21 of 24

22 Outline Statement of the Problem Proposed Microgrid Control Strategy Sample Case Studies Offline Time-Domain Simulations Hardware-in-the-Loop (HIL) Simulations Conclusions Future Research Directions Slide 22 of 24

23 Future Research Directions An Elaborate PMS: Resynchronization, State Estimation, Optimal Power Flow, Unit Commitment, Data Mining, Contingency Analysis DER Control Synchronous Machine DER Units Primary Source Dynamics Nondispatchable Energy Sources (Wind, PV) Energy Storage Mitigation of Imbalance and Harmonic Distortion Microgrid Protection Slide 23 of 24

24 Thank You Amir Etemadi Slide 24 of 24

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26 Overcurrent Protection 5 km 10 km L1 L2 L3 DER1 DER2 DER3

27 Smooth Control Transition 5 km 10 km Grid L1 L2 L3 DER1 DER2 DER3

28 Large Motor Starting 5 km 10 km M L1 L2 L3 Induction DER1 DER2 DER3 Motor

29 Comparison with Droop Control 5 km 10 km L1 L2 L3 M Induction DER1 DER2 DER3 Motor Proposed Strategy Droop Control Droop Control with Voltage Restoration

30 Smooth Islanding