• Title/Summary/Keyword: MGSO

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Applying TID-PSS to Enhance Dynamic Stability of Multi-Machine Power Systems

  • Mohammadi, Ramin Shir;Mehdizadeh, Ali;Kalantari, Navid Taghizadegan
    • Transactions on Electrical and Electronic Materials
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    • v.18 no.5
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    • pp.287-297
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    • 2017
  • Novel power system stabilizers (PSSs) have been proposed to effectively dampen low frequency oscillations (LFOs) in multi-machine power systems and have attracted increasing research interest in recent years. Due to this attention, recently, fractional order controllers (FOCs) have found new applications in power system stability issues. Here, a tilt-integral-derivative power system stabilizer (TID-PSS) is proposed to enhance the dynamic stability of a multi-machine power system by providing additional damping to the LFOs. The TID is an extended version of the classical proportional-integral-derivative (PID) applying fractional calculus. The design of the proposed three-parameter tunable TID-PSS is systematized as a nonlinear time domain optimization problem in which the tunable parameters are adjusted concurrently using a modified group search optimization (MGSO) algorithm. An integral of the time multiplied squared error (ITSE) performance index is considered as the objective function. The proposed stabilizer is simulated in the MATLAB/SIMULINK environment using the FOMCON toolbox and the dynamic performance is evaluated on a 3-machine 6-bus power system. The TID-PSS is compared with both classical PID-PSS (PID-PSS) and conventional PSS (CPSS) using eigenvalue analysis and time domain simulations. Sensitivity analyses are performed to assess the robustness of the proposed controller against large changes in system loading conditions and parameters. The results indicate that the proposed TID-PSS provides the better dynamic performance and robustness compared with the PID-PSS and CPSS.

Effect of Media Compositions on Mycelial Growth of L. edodes

  • Park, Won-Sun;Ji, Yeong-Min;Choe, Jeong-U;Hong, Eok-Gi
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.363-366
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    • 2001
  • This study was to investigate the effects of media components on the mycelial growth of Lentinus eclodes, including C-source. N-source, Inorganic salts, and c/N ratio. Glucose and yeast extract were selected as C-source and N-source, respectively. $KH_2PO_4,\;K_2HPO_4,\;MGSO_4,\;7H_2O$ as inorganic salts were added. When glucose concentration was 30g/L and yeast extract concentration was 20g/L, indicating that C/N ratio was 1.5, the cell mass was about 9g/L.

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Medium Composition of Aspergillus oryzae PF for the Production of Proteolytic Enzyme (단백질 분해효소 생산을 위한 Aspergillus oryzae PF균주의 배지조성)

  • 김두상;김형락;남택정;변재형
    • Microbiology and Biotechnology Letters
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    • v.27 no.5
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    • pp.404-409
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    • 1999
  • The most favorable nitrogen source for the production of protease by Aspergillus oryzae PF was 2% soybean flour among sodium nitrate, ammonium sulfate, defatted soybean, skim milk, casein, peptone, and yeast extract. The production of protease from A. oryzae PF was higher at the concentration of 2% lactose than at variable concentration of glucose, sucrose, soluble starch, corn starch, potato starch, wheat starch, rice starch, cellulose, and gum arabic. Protease production was affected by the concentration of KH2PO4, Triton X-100, CaCo3, and MgSO4, and it was the highest at the highest at the concentration of 3% KH2PO4, 0.01% Triton X-100, 0.3% CaCO3, and 0.06% MGSO4.

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Purification and Properties of Extracellular Protease from Streptomyces rimosus (Streptomyces rimosus가 생산하는 Protease의 정제와 특성)

  • 김경미;이태경;양한철
    • Microbiology and Biotechnology Letters
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    • v.17 no.5
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    • pp.407-411
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    • 1989
  • Extracellular neutral pretense of Streptomyces rimosus producing oxytetracycline was purified by ammonium sulfate fractionation, DEAE Sephadex A-50 chromatography and Sephadex G-100 gel filteration, and was showed single band on the cathodic gel electrophoresis. The optimum pH and temperature of the enzyme were pH 8.0 and 6$0^{\circ}C$, respectively. The enzyme was activated about 80% in the presence of Co$^{2+}$ ion, and strongly inhibited by Hg$^{2+}$, Fe$^{2+}$ and chelatig agent, EDTA. Molecular weight of the enzyme was estimated to be 12, 000. The Km value of the enzyme of casein as a substrate was 2.7$\times$10$^{-4}$M.

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