Dynamic stability improvement with integrated power plant scheduling method based on moment of inertia

Dynamic stability is one of the important aspects of maintaining the stability of an electrical power system as a whole. Dynamic stability study is the ability of the electric power system to return to the equilibrium point after a relatively small disturbance suddenly occurs for a long time. In this paper, we offer a method of rescheduling the generator to improve system stability by looking at the critical clearing time (CCT). Changes in the CCT value are due to changes in the load on each bus. The modelling of the IEEE 14 bus system is carried out with the help of the Simulink Power System Analysis Toolbox (PSAT) 2.1.10, which is integrated with the MATLAB R. 2016a program. The simulation results show that the CCT value decreases as the fault location gets closer to the main generator.

The intensification of industrial salt production using the salt production house concept

The current national salt demand in 2021 is 4.6 million tons, 84% of it: for manufacturing purposes. The volume of imported salt reaches 50.29 percent of the national saltavailability. This high import is caused by lack of the industrial salt. In the 2020-2024 RPJMN, the total national salt production target in 2021 is 3 million tons, not enough, due to the natural conditions of high rainfall. KKP and Kemenkomarves are targeting to increase production through intensification and extensification of salt pond land, which is planned to be carried out in Flores and Sumbawa. However, according to our rough calculation, to meet the amount of national salt need, if the choice is the extensification: this will need 20 thousand hectares of newponds. This is hard option to proceed, because there are obstacles: limited land, not all types of land can be used for salt farming, high costs, long land clearing time, and dependence on weather. Plus, the negative impact on the environment from the land conversion. What is the alternative solution?This study aims to figure the solution for improving the industrial salt production. Methods are the analytical descriptive study, collecting data with reference studies, then compiling data for the formulation of the model. Study results: the suitable option to do is the intensification of the salt production. More efforts are needed on the intensification, by increasing the quantity of salt production, parallel with improving its quality, and could continuously producing salt in a full year. To fulfill this, this study recommends a technological engineering approachment, by using a combination of the Japanese Method with the closed system called: the Salt Production House (SPH). The SPH is green and sustainable concept, because it consumes renewable energy, effective and require a small area. This method requires no new land clearing since it could be constructed on the existing salt ponds.

Lyapunov Analysis of Two Imbalanced Power System Areas

The transient stability is the capability of the system to preserve synchronism while being affected by large disturbances. It is a nonlinear problem that requires a simultaneous solution for many differential equations. Therefore, a thorough analysis is needed to resolve it. In this paper, we present the transient stability for multimachine under different fault cases and to analyze using the Lyapunov function. It serves as an analytical tool to determine the necessary condition to be stable. The system is stable as long as it is contained in the region of attraction. Meanwhile, the swing equation and reduced admittance matrix are used to model the system in three conditions, pre-fault, during the fault, and post-fault. The numerical simulations are conducted to verify that the synchronism can be preserved despite under faults on the transmission lines by achieving the critical clearing time.

Pembersihan Isi Sel Akar dan Jenis Warna Tinta untuk Deteksi Cendawan Mikoriza Arbuskula

Arbuscular mycorrhizal (AM) fungi form mutualistic symbiosis with root of host plant. Staining technique to detect AM fungi usually used hazardous chemical. The ink stain and vinegar were used as an alternative technique to replace trypan blue and lactic acid in root staining method. This study aimed to determine time for clearing root cell contents and ink stain type to visualize the best AM fungal structures within the root observed under light microscope. Pueraria phaseoloides var. javanica roots colonized by AM fungi were cut into 1 cm long, cleared in KOH solution and stained. Four clearing time were done vis 5, 10, 15 and 20 minutes, and four stains were used namely Shaeffer black ink, Parker Quink blue ink, blue stamp ink, and trypan blue. Twenty stained roots were taken randomly from each tratment, and observed. Root clearing process for 20 minutes showed the best result. Only Shaeffer black ink and trypan blue produced clear structure of external hyphae, internal hyphae, vesicles and arbuscules. Arbuscular structure stained only by Shaeffer black ink and trypan blue. This indicated that Shaeffer black ink could be used as an alternative stain to detect AM fungi within the root of host plant

Enhancement Stability of the Power System Using Static Synchronous compensators Connected in Different Formats

The research strategy focuses on the effect of connecting a STATCOM to mend critical-clearing-time (CCT) for the studied system and its transient stability. This paper targets to connect STATCOM in two situations, grouped and distributed. The first situation connects STATCOM at one placement with 100 MVAR reactive power while the second situation connects two STATCOMs at two different placements with the value 50 MVAR for each one and 60 MVAR,40 MVAR in another case. It has been found through this research that when distributing the necessary compensation capacity to more than one static synchronous compensator better than from combined them in one compensator in improving the CCT. It used MATLAB / ver.2017 for simulation of our studied system (IEEE-9 nodes).

Optimal Sizing of Supercapacitor Energy Storage Based on Firefly Algorithm for Enhancing Critical Clearing Time

In the present day, the electrical power demand is increasing and expected to continue growing. The renewable energy sources as the power supply are also increasing but not much as needed. As a result, the power systems operate close to their maximum stability limit. This paper proposed to extend the value of Critical Clearing Time (CCT) to enhance the stability system, especially the transient stability. A Supercapacitor Energy Storage (SCES) is installed at one of the generator bus; however, the sizing of SCES must be optimized due to the economics and power balance constraint. In this paper, the Firefly Algorithm (FA) is used to obtain the optimal sizing of SCES with the objective function is the highest value of CCT. Lagrange interpolation is used to validate the effectiveness of FA, such as computation time and accuracy. According to the simulation result obtained, the proposed method using FA has a faster calculation time than Lagrange interpolation. Moreover, the proposed method is validated on a modified IEEE 9 bus with various cases. By using FA, the best increase of CCT is obtained when the optimal size of SCES is 0.120 p.u. The overall CCT increase is 0.15766s or around 54.61%.