{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T08:47:50Z","timestamp":1759826870971,"version":"build-2065373602"},"reference-count":25,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T00:00:00Z","timestamp":1759795200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"China Southern Grid Digital Grid Funding","award":["DPGCSG-2024-KF-21"],"award-info":[{"award-number":["DPGCSG-2024-KF-21"]}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Symmetry"],"abstract":"<jats:p>The power system\u2019s dynamic frequency stability is affected by common-mode ultra-low-frequency oscillation and differential-mode low-frequency oscillation. Traditional frequency control based on generators is facing the problem of capacity reduction. It is urgent to explore new regulation resources such as photovoltaics. To address this issue, this paper proposes a distributed active support method based on photovoltaic systems via state\u2013disturbance observation and dynamic surface consensus control. A three-layer distributed control framework is constructed to suppress low-frequency oscillations and ultra-low-frequency oscillations. To solve the high-order problem of the regional grid model and to obtain its unmeasurable variables, a regional observer estimating both system states and external disturbances is designed. Furthermore, a distributed dynamic frequency stability control method is proposed for wide-area photovoltaic clusters based on the dynamic surface control theory. In addition, the stability of the proposed distributed active support method has been proven. Moreover, a parameter tuning algorithm is proposed based on improved chaos game theory. Finally, simulation results demonstrate that, even under a 0\u20132.5 s time-varying communication delay, the proposed method can restrict the frequency deviation and the inter-area frequency difference index to 0.17 Hz and 0.014, respectively. Moreover, under weak communication conditions, the controller can also maintain dynamic frequency stability. Compared with centralized control and decentralized control, the proposed method reduces the frequency deviation by 26.1% and 17.1%, respectively, and shortens the settling time by 76.3% and 42.9%, respectively. The proposed method can effectively maintain dynamic frequency stability using photovoltaics, demonstrating excellent application potential in renewable-rich power systems.<\/jats:p>","DOI":"10.3390\/sym17101672","type":"journal-article","created":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T08:05:36Z","timestamp":1759824336000},"page":"1672","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Distributed Active Support from Photovoltaics via State\u2013Disturbance Observation and Dynamic Surface Consensus for Dynamic Frequency Stability Under Source\u2013Load Asymmetry"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7627-015X","authenticated-orcid":false,"given":"Yichen","family":"Zhou","sequence":"first","affiliation":[{"name":"Key Laboratory of Distributed Energy Storage and Microgrid of Hebei Province (North China Electric Power University), Baoding 071003, China"}]},{"given":"Yihe","family":"Gao","sequence":"additional","affiliation":[{"name":"Key Laboratory of Distributed Energy Storage and Microgrid of Hebei Province (North China Electric Power University), Baoding 071003, China"}]},{"given":"Yujia","family":"Tang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of HVDC, Electric Power Research Institute, China Southern Power Grid, Guangzhou 510663, China"},{"name":"National Energy Power Grid Technology R&D Centre, Guangzhou 510663, China"},{"name":"Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System, Guangzhou 510663, China"}]},{"given":"Yifei","family":"Liu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Distributed Energy Storage and Microgrid of Hebei Province (North China Electric Power University), Baoding 071003, China"}]},{"given":"Liang","family":"Tu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of HVDC, Electric Power Research Institute, China Southern Power Grid, Guangzhou 510663, China"},{"name":"National Energy Power Grid Technology R&D Centre, Guangzhou 510663, China"},{"name":"Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System, Guangzhou 510663, China"}]},{"given":"Yifei","family":"Zhang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Distributed Energy Storage and Microgrid of Hebei Province (North China Electric Power University), Baoding 071003, China"}]},{"given":"Yuyan","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of HVDC, Electric Power Research Institute, China Southern Power Grid, Guangzhou 510663, China"},{"name":"National Energy Power Grid Technology R&D Centre, Guangzhou 510663, China"},{"name":"Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System, Guangzhou 510663, China"}]},{"given":"Xiaoqin","family":"Zhang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Distributed Energy Storage and Microgrid of Hebei Province (North China Electric Power University), Baoding 071003, China"}]},{"given":"Jiawei","family":"Yu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of HVDC, Electric Power Research Institute, China Southern Power Grid, Guangzhou 510663, China"},{"name":"National Energy Power Grid Technology R&D Centre, Guangzhou 510663, China"},{"name":"Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System, Guangzhou 510663, China"}]},{"given":"Rui","family":"Cao","sequence":"additional","affiliation":[{"name":"Key Laboratory of Distributed Energy Storage and Microgrid of Hebei Province (North China Electric Power University), Baoding 071003, China"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,7]]},"reference":[{"key":"ref_1","unstructured":"National Grid ESO (2020). 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