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Weak-fault diagnosis using state-transition-algorithm-based adaptive stochastic-resonance method

Journal of Central South University 2019年第7期26卷 1910-1920页

作者： YIN Jin-tian XIE Yong-fang CHEN Zhi-wen PENG Tao YANG Chun-hua School of Automation Central South University Changsha 410083 China Hunan Provincial Key Laboratory of Grids Operation and Control on Multi-Power Sources Area Shaoyang University Shaoyang 422000 China

In the early fault period of high-speed train systems, the interested characteristic signals are relatively weak and easily submerged in heavy noise. In order to solve this problem, a state-transition-algorithm (STA)-based adaptive stochastic resonance (SR) method is proposed, which provides an alternative solution to the problem that the traditional SR has fixed parameters or optimizes only a single parameter and ignores the interaction between parameters. To be specific, the frequency-shifted and re-scaling are firstly used to pre-process an actual large signal to meet the requirement of the adiabatic approximate small parameter. And then, the signal-to-noise ratio is used as the optimization target, and the STA-based adaptive SR is used to synchronously optimize the system parameters. Finally, the optimal extraction and frequency recovery of a weak characteristic signal from a broken rotor bar fault are realized. The proposed method is compared with the existing methods by the early broken rotor bar experiments of traction motor. Experiment results show that the proposed method is better than the other methods in extracting weak signals, and the validity of this method is verified.

关键词： stochastic resonance (SR) state-transition-algorithm (STA) fault diagnosis broken rotor bar

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Time -Frequency Analysis on Earth Fault Signal Response Based on the BLT Equation for MultiBranch Distribution Networks

Time -Frequency Analysis on Earth Fault Signal Response Base...

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Minqiang Li Baiyang Liu Qiuzhen Wei Kun Yu Chen Wang Xiangjun Zeng Hechi Power Supply Bureau Guangxi Power Grid Co Ltd Hechi China Guangxi Key Laboratory of Power System Optimization and Energy Technology Guangxi University Nanning China Hunan Province Key Laboratory of Smart Grids Operation and Control Changsha University of Science and Technology Changsha China

ISBN: (数字)9781728157481

ISBN: (纸本)9781728157498

The BLT equation as the foundation of electromagnetic topology has an advantage in calculation of complex systems, particularly ring and multi-branch networks and is thus widely applied in EMC and EMI fields. In this paper the BLT equation was introduced to the fields of distribution network protection for analyzing the earth fault signal response on each junction of the multi-branch distribution network. The BLT equation was derived and the scattering matrices were determined for the multi-branch distribution network. The voltage responses of earth fault signal on each junction in the time and frequency domain were analyzed. Finally, some conclusions which are benefit for researching and improving the travelling wave-based method were given.

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Reactive power optimization for Distribution Network Based on Improved Bacterial Chemotaxis Particle Swarm optimization

Reactive Power optimization for Distribution Network Based o...

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International Symposium on Computational Intelligence and Design, ISCID

作者： Qiang Huang Jie Tang Hui Li Junfei Nie Hunan Provincial Key Laboratory of Grids Operation and Control on Multi-Power Sources Area Shaoyang China

ISBN: (数字)9781728146539

ISBN: (纸本)9781728146546

In this paper, the mathematical model of reactive power optimization is established by using objective function, in order to minimize the sum of power loss and investment cost of newly added reactive power compensation equipment, and an improved particle swarm optimization algorithm based on bacterial chemotaxis was proposed to solve the model. The algorithm takes particle swarm optimization algorithm as the standard, uses chaotic sequence to initialize the population, to improve the diversity of initial population, change the inertia weight and learning factor by using cosine nonlinear transformation, and enhance the global search and learning ability of particles, improves the accuracy of the algorithm, maintains the population diversity through bacterial chemotaxis, and improves the convergence stability of the algorithm. The simulation results in IEEE 30-bus system verify the effectiveness of the improved PSO algorithm in solving the reactive power optimization problem of distribution network.

关键词： Handheld computers Computational intelligence

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power system Small-signal Stability Assessment Model Based on Residual Graph Convolutional Networks

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Journal of Physics: Conference Series 2021年第1期2095卷

作者： Yinsheng Su Mengxuan Guo Haicheng Yao Lin Guan Jiyu Huang Siting Zhu Zhi Zhong Department of Power System Operation China Southern Power Grid Guangzhou China School of Electric Power South China University of Technology Guangzhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guangzhou China

Small-signal stability (SSA) is important to power system security. A data-driven approach is established for rapid prediction of the power system oscillation characteristics. The key of the approach is the Graph Convolution Networks (GCN) with residual mechanism, which works to aggregate features from high-dimension steady-state operation information and is denoted as ResGCN (RESidual GCN) in the paper. The residual mechanism helps to overcome the network degradation phenomenon. Both the oscillation frequency and damping ratio of multiple modes can be predicted by the proposed model. The performance of the proposed scheme as well as its adaptability to the power system topological changes is verified on the IEEE 39 Bus system.

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Modeling and Simulation of Hydrogeneration system with Doubly Fed Generator 3

Modeling and Simulation of Hydrogeneration System with Doubl...

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3rd IEEE Conference on Energy Internet and Energy system Integration, EI2 2019

作者： Liu, Baiyang Zeng, Xiangjun Xiao, Xiangchun Liu, Dongqi Li, Li Chen, Xiaoping Shaoyang University Hunan Provincial Key Laboratory of Grids Operation and Control on Multi-Power Sources Area Shaoyang China Changsha University of Science and Technology School of Electrical Information Engineering Changsha China Huaihua Design Institute of Water Conservancy and Electric Power Huaihua China

ISBN: (纸本)9781728131375

With growing concerns about renewable energy consumption, pumped storage power plant is becoming a popular concept and thus the modeling of the doubly fed generator based hydrogeneration system becomes an interesting research topic. In this paper the power control strategy on the doubly fed generator based on pumped storage power plant with the aim of active power and slip control was studied. Multi-index control was employed to achieve the independent control of active power and slip of the machine. The machine was modeled in state equations in a synchronous reference frame. The complete simulation model was developed for such hydrogeneration system under variable speed operation using MATLAB Simulink environment for obtaining the optimal parameters of multi-index control and the dynamic performance got further improved. © 2019 IEEE.

关键词： Energy utilization

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Monitoring Method of Injection-type Generator Stator-to-earth Insulation State in Neutral Point Combined Grounding Mode

Monitoring Method of Injection-type Generator Stator-to-eart...

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IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Xinqi Chen Linbi Xu Lihang Zhao Hangjie Han Bin Tang Kun Yu Li Li Xiangjun Zeng Zhejiang Provincial Key Laboratory of Energy Conservation & Pollutant Control Technology for Thermal Power Zhejiang Zheneng Electric Power Co.Ltd Hangzhou China Zheneng Zhenhai Power Generation Co. Ltd. Zheneng Zhenhai Power Generation Co. Ltd Hangzhou China Hunan Province Key Laboratory of Smart Grids Operation and Control Changsha University of Science and Technology Changsha China

ISBN: (数字)9781728196060

ISBN: (纸本)9781728196077

Aiming at the incompatibility of the existing protection method for the measurement of the ground insulation state under the combined grounding method of the generator stator neutral point (resistance parallel reactor on the secondary side of the grounding transformer), an injection-type monitoring method of insulation state of generator stator to ground in neutral point combined grounding mode is proposed in this paper. By connecting the variable frequency power injecting AC variable frequency signal supplied to the secondary side of the arc suppression coil reactor at the neutral point of the generator, it can search the resonance frequency of stator inductance and capacitance, and calculate the insulation state caused by the insulation damage of stator winding. So it can achieve the purpose that generator stator's insulation state can be real-time monitored. Through modeling and analysis in PSCAD/EMTDC, this method can be adapted to the measurement of the ground insulation state under the combined grounding mode of the generator stator neutral point and obtain the size of the excessive resistance.

关键词： Resistance Insulation Grounding Stator windings Resonant frequency Generators Monitoring

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Feasibility Analysis of Single-end Equivalent Modeling to LCC-HVDC Transimission system

Feasibility Analysis of Single-end Equivalent Modeling to LC...

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IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Bin Wang Zhizhong Li Qi Guo Zhijiang Liu Shuyong Li Liu Cui Tsinghua University Beijing China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System State Key Laboratory of HVDC (Electric Power Research Institute China Southern Power Grid) Guangzhou China National Energy Power Grid Technology R&D Centre State Key Laboratory of HVDC (Electric Power Research Institute China Southern Power Grid) Guangzhou China China Southern Power Grid State Key Laboratory of HVDC (Electric Power Research Institute China Southern Power Grid) CSG Key Laboratory for Power System Simulation Electric Power Research Institute Guangzhou China

ISBN: (数字)9781728196060

ISBN: (纸本)9781728196077

The commutation failures seriously threaten the safe operation of hybrid AC/DC grid. Considering that commutation failure occurs only on the inverter side, it is very important to study the voltage controlled current source model of LCC HVDC single terminal measurement information with high equivalent accuracy, which is very important for the practicality of real-time electromagnetic transient simulation of LCC HVDC dynamic phasor model. In order to this problem, this paper further discusses the single terminal equivalent model of LCC HVDC system which does not depend on the measurement information of DC sending end AC system, and explores the estimation method of single terminal fast transient response of complex AC/DC coupling faults induced by AC side fault of LCC HVDC inverter station and participation of DC control separation. The error distribution of single terminal equivalent calculation is quantitatively analyzed to lay a foundation for the follow-up protection and control technology research.

关键词： Analytical models Solid modeling Voltage measurement HVDC transmission Estimation Inverters Voltage control

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Design of digital control High-voltage DC power Supply

Design of digital Control High-voltage DC Power Supply

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International Symposium on Computational Intelligence and Design, ISCID

作者： Hui Li Jie Tang Li Lin Hunan Provincial Key Laboratory of Grids Operation and Control on Multi-power Sources Area Shaoyang University Shaoyang China

ISBN: (数字)9781728146539

ISBN: (纸本)9781728146546

In order to detect electro-osmosis flow conveniently, a digital small-power high-voltage DC (HDC) power supply based on DSP is introduced which is fully controllable and fast response. The structure of the main circuit is Buck converter which is controlled by the voltage PWM control technology. A voltage feedback closed loop is used in the circuit, in which the digital optical fiber is used for isolation and transmission. Addition to data collection, the DSP controller calculates the duty cycle, which is based on the feedback signal, so that the output voltage can be real-timely traced and monitored. Consequently, the principle of whole system including control circuit and main circuit is described. Finally, the feasibility of the proposed approach is verified on a simulink model with 220V input and 4000V/1mA output. The results show that the HDC system meets the need of automatically detect electroosmosis experiment and gives full play to the convenience of digital power and control.

关键词： power supplies High-voltage techniques Integrated circuit modeling Voltage control Pulse width modulation Microfluidics

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Transient Voltage Stability Assessment Method based on gcForest

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Journal of Physics: Conference Series 2021年第1期1914卷

作者： Sun Zhiyuan LI Mingpo Zhang Jie Hu Binjiang Qi Guo Zhu Yihua Guangxi Power Grid Electrical Power Research Institute Supported by the Science and Technology Project of Guangxi Power Grid (Contract No(***DL00006)). State Key Laboratory of HVDC Electric Power Research Institute CSG China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System CSG Key Laboratory of Power System Simulation

Aiming at the fact that the traditional method cannot quickly and accurately judge the power system transient voltage stability, and the deep neural network method needs many sample data sets and has a large number of hyperparameters, a power system transient voltage stability assessment method based on deep forest (gcForest) is proposed. gcForest effectively extracts features through ensemble learning, multi-layer feature transformation, and dynamically adjusting the number of model layers. Finally, this method is applied to transient voltage stability assessment of an electrolytic aluminium load-intensive area in Guangxi power Grid. The results show that the method has high accuracy, the feasibility and effectiveness of this method are verified. This method can assist dispatchers to judge the transient voltage stability of the power grid.

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Multi-task Transient Contingency Screening with Temporal Graph Convolutional Network in power systems

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Journal of Physics: Conference Series 2021年第1期2095卷

作者： Yinsheng Su Jiyu Huang Haicheng Yao Lin Guan Mengxuan Guo Zhi Zhong Department of Power System Operation China Southern Grid Co. Ltd. School of Electric Power South China University of Technology Guangzhou 510641 P.R. China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guangzhou 510663 China

Rapid transient stability assessment (TSA) is an essential requirement for power system security. In real-world applications, transient contingency screening (TCS) applies TSA approaches to address the pre-defined contingency sets under online operation conditions. TSA by time domain simulation (TDS) is time-consuming, hence we propose a high-speed temporal graph convolutional network (TGCN) that achieves TSA decisions such that a large-scale contingency set can be scanned quickly with enough precision. Based on multi-graph inputs to reflect the transient process, the TGCN utilizes the graph convolutional network (GCN) to extract topology representations and temporal convolution (TC) layers to encode temporal relations. After above graph embedding, two downstream networks are designed for stability classification and critical generator prediction, respectively. Test results on IEEE 39 Bus system demonstrate its superiority over existing models under different operation topologies, fault locations and clearing modes.

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