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This paper proposes local reactive power control to mitigate the voltage fluctuation in medium-voltage systems using DSTATCOMs and photovoltaic (PV) inverters. New expressions are developed to estimate voltage fluctuations and reactive power compensations by transforming line segment power-flow variables into nodal power injections. Using local measurements of voltages and solar powers, the method can provide a fast estimation of reactive power compensations to maintain the voltage at every bus. DSTATCOMs are also properly allocated to enhance the voltage controllability. Coordinated control of multiple reactive power resources is investigated as well. One-second solar irradiance along with one-minute home loads is used to demonstrate the effectiveness of the proposed method.

The research was conducted in 2022 in areas where Erythrophleum fordii Oliver naturally grows in Bac Giang Province, Vietnam. The objective was to determine the distribution and silvicultural attributes of E. fordii, including its structural features and regeneration. The study results identified that E. fordii is naturally distributed in five districts of Bac Giang Province: Luc Nam, Luc Ngan, Yen The, Son Dong, and Tan Yen. E. fordii is widely distributed at altitudes ranging from 50 to 500 m, with a prominent presence between 100 and 200 m above sea level. As the altitude increases, the occurrence of E. fordii decreases. The forest areas dominated by E. fordii exhibit rich biodiversity, particularly in primary evergreen broadleaved forests on mountain soils, with a total of 71 species. The number of species contributing to the forest structure ranges from 9 to 15, depending on the forest condition. The study also revealed that E. fordii has a high composition coefficient, followed by Burseraceae, Chestnut, Jambolan, Elaeocarpus, Engelhardtia chrysolepis Hance, among others. The natural regeneration of E. fordii is low, with an average density of 680 trees per ha and 8 trees per route. However, the regeneration quality is poor. The dominance of regenerated trees varies significantly with altitude, decreasing as the altitude elevates. [ABSTRACT FROM AUTHOR]