Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion
Recent studies show that the loss of stability for a voltage-source converter (VSC) in weak-grid connection is largely related to its synchronization unit, i.e., the phase-locked loop (PLL). This paper studies the synchronization stability of a system comprised by two VSCs in parallel connection to...
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MDPI AG
2020-06-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/13/13/3316 |
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| author | Dong Wang Xiaojie Zhang Lei Yang Yunhui Huang Wei Huang Chen Wu Shengnan Li |
| author_facet | Dong Wang Xiaojie Zhang Lei Yang Yunhui Huang Wei Huang Chen Wu Shengnan Li |
| author_sort | Dong Wang |
| collection | DOAJ |
| description | Recent studies show that the loss of stability for a voltage-source converter (VSC) in weak-grid connection is largely related to its synchronization unit, i.e., the phase-locked loop (PLL). This paper studies the synchronization stability of a system comprised by two VSCs in parallel connection to a weak grid. A reduced transfer function based small-signal model, which can allow for the interactions between PLL and converter outer power controls, is first proposed. Then, an improved net damping criterion is used to analyze the damping and stability characters of such system under various operating conditions and different controller configurations. Compared to the conventional net damping criterion, the used criterion has wider applicability in terms of stability judgment. Case studies show that the studied system tends to be unstable at weak-grid or heavy-loading conditions. The instability can be in the form of oscillations or monotonic divergence, in which, the latter is more likely to occur for the converters without grid voltage regulation capabilities. Besides, the net damping-based sensitivity studies can provide guidance on control tuning or design for stability enhancement. Detailed model-based time domain simulations are conducted to verify the analysis results. |
| first_indexed | 2024-03-10T18:49:57Z |
| format | Article |
| id | doaj.art-fff186ccd3b143afa675101b3084dbee |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T18:49:57Z |
| publishDate | 2020-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-fff186ccd3b143afa675101b3084dbee2023-11-20T05:17:18ZengMDPI AGEnergies1996-10732020-06-011313331610.3390/en13133316Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping CriterionDong Wang0Xiaojie Zhang1Lei Yang2Yunhui Huang3Wei Huang4Chen Wu5Shengnan Li6Department of Electrical Engineering, School of Automation, Wuhan University of Technology, Wuhan 430070, ChinaState Key Laboratory of Advanced Electromagnetic Engineering and Technology, and School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, ChinaElectric Power Research Institute of Yunan, Kunming 650217, ChinaDepartment of Electrical Engineering, School of Automation, Wuhan University of Technology, Wuhan 430070, ChinaElectric Power Dispatching and Control Center of Yunan, Kunming 650200, ChinaElectric Power Dispatching and Control Center of Yunan, Kunming 650200, ChinaElectric Power Research Institute of Yunan, Kunming 650217, ChinaRecent studies show that the loss of stability for a voltage-source converter (VSC) in weak-grid connection is largely related to its synchronization unit, i.e., the phase-locked loop (PLL). This paper studies the synchronization stability of a system comprised by two VSCs in parallel connection to a weak grid. A reduced transfer function based small-signal model, which can allow for the interactions between PLL and converter outer power controls, is first proposed. Then, an improved net damping criterion is used to analyze the damping and stability characters of such system under various operating conditions and different controller configurations. Compared to the conventional net damping criterion, the used criterion has wider applicability in terms of stability judgment. Case studies show that the studied system tends to be unstable at weak-grid or heavy-loading conditions. The instability can be in the form of oscillations or monotonic divergence, in which, the latter is more likely to occur for the converters without grid voltage regulation capabilities. Besides, the net damping-based sensitivity studies can provide guidance on control tuning or design for stability enhancement. Detailed model-based time domain simulations are conducted to verify the analysis results.https://www.mdpi.com/1996-1073/13/13/3316weak gridVSCPLLnet damping criterionsynchronization stability |
| spellingShingle | Dong Wang Xiaojie Zhang Lei Yang Yunhui Huang Wei Huang Chen Wu Shengnan Li Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion Energies weak grid VSC PLL net damping criterion synchronization stability |
| title | Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion |
| title_full | Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion |
| title_fullStr | Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion |
| title_full_unstemmed | Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion |
| title_short | Analysis of Synchronization Stability for Multi VSCs Parallel-Connected to Weak Grids by Improved Net Damping Criterion |
| title_sort | analysis of synchronization stability for multi vscs parallel connected to weak grids by improved net damping criterion |
| topic | weak grid VSC PLL net damping criterion synchronization stability |
| url | https://www.mdpi.com/1996-1073/13/13/3316 |
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