| 1. |
- Farhang, P., et al.
(author)
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Combined design of VSC-HVDC and PSS controllers for LFO damping enhancement
- 2014
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In: Transactions of the Institute of Measurement and Control. - : SAGE Publications. - 1477-0369 .- 0142-3312. ; 36:4, s. 529-540
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Journal article (peer-reviewed)abstract
- The purpose of this paper is to present a novel combined design of the voltage source converter–high voltage direct current (VSC-HVDC) and the power system stabilizer (PSS) controllers to obtain a better dynamical response. The proposed technique is applied to enhance the damping of the power system low-frequency oscillations (LFOs) and results are compared with traditional design. A fuzzy logic controller is designed for PSS (FPSS). Then, a chaotic optimization algorithm, which has a strong ability for finding the most optimistic results, is employed, in presence of FPSS, to search for optimal VSC-HVDC output feedback controller parameters. Moreover, a singular value decomposition method is utilized to select the most effective damping control signal of the VSC-HVDC output feedback controllers. The novel proposed controllers are evaluated on an AC/DC power system. The simulation results demonstrate that the combined controllers have an excellent capability for damping power system LFOs and greatly enhance the dynamic stability of the power system. Also, the system performance analysis under different operating conditions and some performance indices show the effectiveness of the proposed controllers. The benefit of the suggested procedure is greatly improving the dynamic response of the system. In addition, the overshoots, undershoots and the settling times are dramatically reduced by applying the proposed method.
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| 2. |
- Ivanov, I. I., et al.
(author)
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Expanding catalytic sensor capabilities to combustible gas mixtures monitoring
- 2022
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In: Measurement. - : Elsevier. - 0263-2241 .- 1873-412X. ; 194
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Journal article (peer-reviewed)abstract
- Preventing the explosion of mixtures of combustible gases and vapors is an important task in industry. This research presents an approach for rapid assessment of the explosiveness of combustible gas mixtures of unknown composition. The technique is based on registering the amount of heat released during the combustion of a portion of gases inside the catalytic sensor. The phenomenological theory of the approach for rapid assessment of the explosiveness was also presented. To carry out the measurements, a two-stage heating pulse and an approach to the calibration of the catalytic sensor were developed. The experiments were carried out for various mixtures of methane, propane, butane and hexane within the pre-explosive range (up to 50% Low Explosive Limit). In order to calculate the Lower Explosive Limit (LEL) of a mixture of flammable gases, Le Chatelier's rule was used. Industrial catalytic sensors with additional diaphragm that limits the gas leakage into the sensor were used for measurements. The advanced data processing which is based on integrating the area under the measured dependence of sensor response on time was used to calculate the heat released. The parameters affecting the measurement results were analyzed. The measurement values were in good agreement with the prescribed values. The measurement errors did not exceed 10%. Since in this approach there is no need to identify gases, or their quantity and concentration, it can be used in industry for quick determination of potentially explosive mixtures in the air.
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