Research on Partial Discharge Pattern Recognition in GIS Based on EFPI Sensor

Wang Zan,Liu Zhongquan,Qiao Lili,Qian Dingdong,Chen Zhongxian,Gao Chaofei,Wang Wei 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

An EFPI fber optic ultrasonic sensor can be used for the detection and pattern recognition of partial discharge ultrasonic signals in Gas Insulated Switchgear. Compared with traditional piezoelectric sensors, it has many advantages, such as high sensitivity and strong anti-interference ability. Based on this, four typical PD models of the tip, metal particles, suspension and creeping surface were set up in the GIS cavity flled with 0.4 MPa SF6 gas, and the EFPI sensor was innovatively used to detect the discharge ultrasonic signal and extract the single ultrasonic pulse signal. The waveform features form a feature parameter database, and the probabilistic neural network algorithm and the support vector machine algorithm are used for pattern recognition and comparative analysis, respectively. The ultrasonic signal detected by the EFPI sensor has prominent features. On the basis of extracting the feature parameters, the two pattern recognition algorithms can achieve an average recognition rate of more than 85%, and the recognition efect of the support vector machine is better than that of the probabilistic neural network

Adaptive Granule Control with the Aid of Rough Set Theory for a HVDC system

왕중선(Zhongxian Wang),양정제(Jeungje Yang),안태천(Taechon Ahn) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.11

A proportional intergral (PI) control strategy is commonly used for constant current and extinction angle control in a HVDC (High Voltage Direct Current) system. A PI control strategy is based on a stactic design where the gains of a PI controller are fixed. Since the response of a HVDC plant dynamically changes with variations in the operation point, a PI controller performance is far from optimum. The contribution of this paper is the presentation of the design of a rough set based, fuzzy adaptive control scheme. Experimental results that compare the performance of the adaptive control and PI control schemes are also given.

Genetically optimized self-tuning Fuzzy-PI controller for HVDC system

왕중선(Zhongxian Wang),양정제(Juengje Yang),안태천(Taechon Ahn) 대한전기학회 2006 정보 및 제어 심포지엄 논문집 Vol.2006 No.1

In this paper, we study an approach to design a self-tuning Fuzzy-PI controller in HVDC(High Voltage Direct Current) system. In the rectifier of conversional HVDC system, turning on, turning off, triggering and protections of thyristors have lots of problems that can make the dynamic instability and cannot damp the dynamic disturbance efficiently. The above problems are solved by adapting Fuzzy-PI controller for the fire angle control of rectifier.[7] The performance of the Fuzzy-PI controller is sensitive to the variety of scaling factors. The design procedure dwells on the use of evolutionary computing(Genetic Algorithms, GAs). Then we can obtain the optimal scaling factors of the Fuzzy-PI controller by Genetic Algorithms. In order to improve Fuzzy-PI controller, we adopt FIS to tune the scaling factors of the Fuzzy-PI controller on line. A comparative study has been performed between Fuzzy-PI and self-tuning Fuzzy-PI controller. to prove the superiority of the proposed scheme.

Research for the bearing fit effect on the vibration characteristics of spindle rotor-bearing system

Zhan Wang,Siyang Chen,Wenzhi He,Zinan Wang,Zhongxian Xia 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

Spindle bearing fits mainly include interference fit of inner ring and clearance fit of outer ring, which directly affect the vibration characteristics of spindle rotor-bearing system. In this paper, the influence of spindle bearing inner and outer ring fits on bearing support stiffness is firstly studied. Considering the spindle bearing inner and outer ring fits, a dynamic model of spindle rotor-bearing system is established. Then, the analysis methods of bifurcation and time domain are used to perform simulation analysis. The influence of bearing fit on the vibration characteristics of rotor system is researched. Lastly, at different rotating speeds, bearing fits experiments are conducted on built motorized spindle test platform, which verifies the correctness of the dynamic model. The results show that the influence of bearing fit on vibration is nonlinear. The influence of clearance fit on vibration is smaller, when the clearance fit value of bearing outer ring is about 4-6 μm. The vibration characteristics of rotor are more sensitive to the clearance fit of bearing outer ring than the interference fit of bearing inner ring. The research work provides an important theoretical basis for the optimal of spindle bearing assembly.

Three-dimensional Adaptive Sliding Mode Guidance Law for Missile with Autopilot Lag and Actuator Fault

Guiying Li,Zhigang Yu,Zhongxian Wang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.6

This paper investigates guidance scheme for missile with actuator failure and dynamics of autopilot. Firstly, considering first-order dynamics of autopilot, the guidance model with actuator failure is established. Secondly, an adaptive sliding mode fault-tolerant guidance law is designed on the basis of passive fault-tolerant technique and a novel nonsingular fast terminal sliding mode (NFTSM) manifold. Then, the adaptive algorithm with the feature of low-pass filter is proposed to ensure that adaptive parameters are bounded when the sliding mode is non-ideal. Finally, Lyapunov stability theory is adopted to prove that the states of closed-loop system are practical finite-time stability. Simulation results demonstrate the effectiveness and robustness of the proposed guidance strategy under the certain actuator failure.

Impact response of ultra-high performance fiber-reinforced concrete filled square double-skin steel tubular columns

Jie Li,Weiqiang Wang,Chengqing Wu,Zhongxian Liu,Pengtao Wu 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.3

This paper studies the lateral impact behavior of ultra-high performance fiber-reinforced concrete (UHPFRC) filled double-skin steel tubular (UHPFRCFDST) columns. The impact force, midspan deflection, and strain histories were recorded. Based on the test results, the influences of drop height, axial load, concrete type, and steel tube wall thickness on the impact resistance of UHPFRCFDST members were analyzed. LS-DYNA software was used to establish a finite element (FE) model of UHPFRC filled steel tubular members. The failure modes and histories of impact force and midspan deflection of specimens were obtained. The simulation results were compared to the test results, which demonstrated the accuracy of the finite element analysis (FEA) model. Finally, the effects of the steel tube thickness, impact energy, type of concrete and impact indenter shape, and void ratio on the lateral impact performances of the UHPFRCFDST columns were analyzed.

Magnetic biochar from alkali-activated rice straw for removal of rhodamine B from aqueous solution

Zhaogang Ren,Fang Chen,Bin Wang,Zhongxian Song,Ziyu Zhou,Dong Ren 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.4

To address organic dye wastewater, economic and effective adsorbents are required. Here, magnetic biochar from alkali-activated rice straw (AMBC) was successfully synthesized using one-step magnetization and carbonization method. The alkaline activation caused the large specific surface area, high pore volume and abundant oxygen-containing groups of the AMBC, and the magnetization gave the AMBC a certain degree of electropositivity and fast equilibrium characteristics. These characteristics collectively contributed to a relative high adsorption capacity of 53.66 mg g<SUP>−1</SUP> for this adsorbent towards rhodamine B (RhB). In brief, RhB can spontaneously adsorb onto the heterogeneous surface of the AMBC and reach the equilibrium in 60 min. Although the initial pH, ionic strength and other substances of the solution affected the adsorption performance of the AMBC, it could be easily regenerated and reused with considerable adsorption content. Based on the results, H-bonds, π–π stacking and electrostatic interactions were speculated as the primary mechanisms for RhB adsorption onto the AMBC, which was also demonstrated by the FTIR analysis. With the advantageous features of low cost, easy separation, considerable adsorption capacity and favorable stability and reusability, the AMBC would be a potential adsorbent for removing organic dyes from wastewater.