Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints
Micro-grids’ operations offer local reliability; in the event of faults or low voltage/frequency events on the utility side, micro-grids can disconnect from the main grid and operate autonomously while providing a continued supply of power to local customers. With the ever-increasing penetration of...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-05-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/15/10/3662 |
| _version_ | 1797500181766209536 |
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| author | Mikhail A. Bragin Bing Yan Akash Kumar Nanpeng Yu Peng Zhang |
| author_facet | Mikhail A. Bragin Bing Yan Akash Kumar Nanpeng Yu Peng Zhang |
| author_sort | Mikhail A. Bragin |
| collection | DOAJ |
| description | Micro-grids’ operations offer local reliability; in the event of faults or low voltage/frequency events on the utility side, micro-grids can disconnect from the main grid and operate autonomously while providing a continued supply of power to local customers. With the ever-increasing penetration of renewable generation, however, operations of micro-grids become increasingly complicated because of the associated fluctuations of voltages. As a result, transformer taps are adjusted frequently, thereby leading to fast degradation of expensive tap-changer transformers. In the islanding mode, the difficulties also come from the drop in voltage and frequency upon disconnecting from the main grid. To appropriately model the above, non-linear AC power flow constraints are necessary. Computationally, the discrete nature of tap-changer operations and the stochasticity caused by renewables add two layers of difficulty on top of a complicated AC-OPF problem. To resolve the above computational difficulties, the main principles of the recently developed “<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>l</mi><mn>1</mn></msub></semantics></math></inline-formula>-proximal” Surrogate Lagrangian Relaxation are extended. Testing results based on the nine-bus system demonstrate the efficiency of the method to obtain the exact feasible solutions for micro-grid operations, thereby avoiding approximations inherent to existing methods; in particular, fast convergence of the method to feasible solutions is demonstrated. It is also demonstrated that through the optimization, the number of tap changes is drastically reduced, and the method is capable of efficiently handling networks with meshed topologies. |
| first_indexed | 2024-03-10T03:58:11Z |
| format | Article |
| id | doaj.art-956fca0967994c52a3117fa1189a4ed4 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T03:58:11Z |
| publishDate | 2022-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-956fca0967994c52a3117fa1189a4ed42023-11-23T10:51:21ZengMDPI AGEnergies1996-10732022-05-011510366210.3390/en15103662Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer ConstraintsMikhail A. Bragin0Bing Yan1Akash Kumar2Nanpeng Yu3Peng Zhang4Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269, USADepartment of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester, NY 14623, USADepartment of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester, NY 14623, USADepartment of Electrical and Computer Engineering, University of California, Riverside, CA 94143, USADepartment of Electrical and Computer Engineering, Stony Brook University, Stony Brook, NY 11794, USAMicro-grids’ operations offer local reliability; in the event of faults or low voltage/frequency events on the utility side, micro-grids can disconnect from the main grid and operate autonomously while providing a continued supply of power to local customers. With the ever-increasing penetration of renewable generation, however, operations of micro-grids become increasingly complicated because of the associated fluctuations of voltages. As a result, transformer taps are adjusted frequently, thereby leading to fast degradation of expensive tap-changer transformers. In the islanding mode, the difficulties also come from the drop in voltage and frequency upon disconnecting from the main grid. To appropriately model the above, non-linear AC power flow constraints are necessary. Computationally, the discrete nature of tap-changer operations and the stochasticity caused by renewables add two layers of difficulty on top of a complicated AC-OPF problem. To resolve the above computational difficulties, the main principles of the recently developed “<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>l</mi><mn>1</mn></msub></semantics></math></inline-formula>-proximal” Surrogate Lagrangian Relaxation are extended. Testing results based on the nine-bus system demonstrate the efficiency of the method to obtain the exact feasible solutions for micro-grid operations, thereby avoiding approximations inherent to existing methods; in particular, fast convergence of the method to feasible solutions is demonstrated. It is also demonstrated that through the optimization, the number of tap changes is drastically reduced, and the method is capable of efficiently handling networks with meshed topologies.https://www.mdpi.com/1996-1073/15/10/3662micro-gridsdroop controlstap changersislanded modeAC OPFLagrangian relaxation |
| spellingShingle | Mikhail A. Bragin Bing Yan Akash Kumar Nanpeng Yu Peng Zhang Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints Energies micro-grids droop controls tap changers islanded mode AC OPF Lagrangian relaxation |
| title | Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints |
| title_full | Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints |
| title_fullStr | Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints |
| title_full_unstemmed | Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints |
| title_short | Efficient Operations of Micro-Grids with Meshed Topology and Under Uncertainty through Exact Satisfaction of AC-PF, Droop Control and Tap-Changer Constraints |
| title_sort | efficient operations of micro grids with meshed topology and under uncertainty through exact satisfaction of ac pf droop control and tap changer constraints |
| topic | micro-grids droop controls tap changers islanded mode AC OPF Lagrangian relaxation |
| url | https://www.mdpi.com/1996-1073/15/10/3662 |
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