Advances in Energy Power and Automation Engineering

Inhaltsverzeichnis

1. Power System and Power Equipment Modeling

   1. Frontmatter

   2. Parameter Identification for Transformer Winding Equivalent Networks Based on an Improved Whale Optimization Algorithm

      Yong Liu, Xiaobo Pei, Yuye Gong, Qinggong Qi, Yongsheng Zhu, Xiaolei Wang

      Abstract

      Identifying the equivalent network parameters of the transformer winding is essential for the interpretation of the frequency response analysis (FRA) and driving-point admittance (DPA) data. This chapter presents a method for parameter identification that uses the DPA data and the improved whale optimization algorithm (IWOA) to invert the equivalent network parameters of the transformer. First, the DPA measurement model and its state-space equation of a double-winding transformer were established. Next, an objective function was constructed by the resonant amplitudes of the reference DPA curve and that of the estimation DPA derived by the above-mentioned state space equation. Then, an improved whale algorithm was proposed by updating the population generation method, the convergence factor, and the inertia weight of the whale algorithm. Finally, the validity and advantage of the parameter recognition method, based on the objective function and the IWOA, were proved by identifying the parameters of the simulation model and the comparison with the particle swarm optimization (PSO) and genetic algorithm (GA) algorithms.

   3. Decoupled Spatial–Temporal Model for Temperature Field Prediction of Transformer

      Hao Liu, Jinrui Gan, Qiang Zhang, Jie Tong, Zhonghao Zhang, Pengfei Tang, Qiong Fang, Songyuan Li, Chi Zhang

      Abstract

      As an important energy conversion equipment in the power grid, power transformers have a complex temperature field, which is related to their own operation life and the stability of the power system. Therefore, accurately obtaining the characteristics of the temperature field and hot spot temperature of transformers has important practical value. At present, there are two methods for constructing the temperature field of transformers, including model driven and data driven. However, existing data-driven methods couple temporal and spatial information when constructing networks, resulting in imbalanced spatiotemporal modeling and making the network training process difficult. Therefore, we propose a transformer temperature field prediction method based on spatiotemporal decoupling training, including spatial feature vector quantification and temporal feature modeling. It can balance the spatiotemporal modeling process, reduce the difficulty of model training, and effectively improve the accuracy of transformer temperature field prediction.

   4. The Differentiated Lightning Protection Modification of the Inlet Section Considering the Characteristic Change of the Station Lightning Arrester

      Wenhua Zhao, Qiuyang Li, Taohui Yang, Zhiqing Ma, Ling Jiang, Yitao Zhang

      Abstract

      The substation line is usually located in the high-voltage area of the system. Although the general lightning protection reform measures for it will strengthen the lightning resistance level of the line and improve the operation reliability, they will also increase the lightning intrusion wave of the substation, which will have an impact on the insulation coordination of the equipment in the station to a certain extent, especially affecting the characteristics of the lightning arrester, resulting in the increase of overcurrent and heat, and then shortening its service life. In summary, taking a 330 kV substation and its line segment in a high-altitude area as an example, ATP-EMTP (the Alternative Transients Program—the Alternative Transients Program) was used to establish a simulation model, and the influences of different poles and towers in the line segment on the current and overvoltage of the arrester in the station were, respectively, explored. Based on this, considering the condition of the line body and the insulation cooperation with the equipment in the station, the differentiated lightning protection transformation of the line segment is finally realized.

   5. Automatic Classification of Substation Equipment Based on Multi-View Inspection Images

      Duanjiao Li, Ying Zhang, Yun Chen, Junwen Yao, Ziran Jia

      Abstract

      In addressing the automatic recognition and classification of equipment in the construction of smart substations, we propose a method based on multi-view inspection images for automatic classification of substation equipment. This method utilizes the YOLOv8 object detection algorithm for automatic classification of substation equipment. Through multi-view inspections of substation equipment to capture images from different angles, a segmented substation equipment sample set is used to train the YOLOv8 algorithm. The collected data is preprocessed, and the trained YOLOv8 algorithm is then used to classify and recognize images, achieving automatic classification of substation equipment. Experimental results demonstrate the successful detection of various types of substation equipment, including disconnectors, racks, insulating porcelain bottles, current transformers, surge arresters, and circuit breakers. At a threshold of 0.5, the average recognition accuracy for all classes is 0.502, indicating the application potential of the YOLOv8 algorithm in substation equipment recognition tasks. This method can provide certain technical support for the construction of smart substations.

   6. Simulation Research on Distribution Network Based on Improved Transmission Line Decoupling Method

      Ruihan Wang, Guochu Chen

      Abstract

      This chapter explores the problem of decoupling distribution networks through an improved distributed parametric long-line decoupling method. The traditional long-line decoupling method has certain limitations when applied to the distribution network, mainly due to the short-line characteristics in the distribution network, which cannot fully utilize the transmission delay decoupling. In response to this problem, this chapter proposes an improved line decoupling method. This improved method introduces compensation capacitance to increase the wave propagation time without changing the line length, thereby realizing the decoupling of lines in the distribution network. And by building a model for simulation analysis, the effectiveness of the method is verified, providing new ideas and methods for solving the decoupling problem of distribution networks.

   7. Recommended Protection to Prevent Safety-Related Motors from Losing All AC Power When an Open Phase Fault Occurs in the Auxiliary Transformer of a Nuclear Power Plant

      Jinjun Lu, Geling Jiang

      Abstract

      The primary objective of this study is to address the issue of complete AC power loss of safety class motors within nuclear power plants in the event of an open phase fault occurring in the auxiliary transformer. The analysis commences by examining the mechanism responsible for inducing voltage on the primary side following an open phase fault in transformers featuring d-type windings on the secondary side. It employs positive sequence and negative sequence equivalent circuit models for motors to assess voltage and current behaviors during this fault. The study then shifts its focus to how the voltage of the auxiliary transformer and the safety-related motor respond to variations in grounding resistance and auxiliary transformer load ratio. The analysis reveals that when the grounding resistance falls within the range of 500 to 2500 Ω, the safety-related motor in the unit may lose its entire AC power supply. Moreover, if the grounding resistance exceeds 2500 Ω and the auxiliary transformer bears even a minimal load, the safety-related motor will lose all AC power due to a significant imbalance. In conclusion, the chapter proposes a solution by introducing a negative sequence phase voltage imbalance protection relay. This approach ensures that, in the event of an open-phase fault, there will be no adverse impact on the safety-related motor. In other words, it will prevent equipment damage or false tripping and guarantee that the safety-related motor does not lose its entire AC power supply, thus contributing to the overall safety and stability of nuclear power plant operations.

   8. Analysis of Load Characteristics of Floating Wind Turbines Under Combined Wind and Wave Actions

      Deshun Li, Zhicheng Zhu, Yuan Hu, Shengfu Mo, Xiaobo Zheng

      Abstract

      In this chapter, the vibration response characteristics of NREL’s 15 MW floating wind turbine under the environmental combination of wind shear incoming flow, turbulent wind, and regular and irregular wave conditions are investigated by numerical simulations with OpenFAST software. It is found that the wave load mainly affects the fore-aft shear at the base of the tower, where the irregular wave has the most significant effect on the response value; the turbulent wind significantly increases the volatility of the side-to-side shear at the base of the tower. The environmental contour method is used to predict the ultimate response of the unit, and the study shows that the wind turbine will show the ultimate response under specific conditions, which are as follows: under the conditions of wind speed of 10 m/s, significant wave height of 5.36 m, and spectral period of 11.61 s, the fore-aft shear at the tower base of the wind turbine will show the ultimate response; under the conditions of wind speed of 25 m/s, significant wave height of 3.95 m, and spectral period of 6.23 s, the side-to-side shear at the base of the tower will show the ultimate response. The side-to-side shear at the base of the tower shows the limit response for the case of wind speed 25 m/s and spectral period 6.23 s.

   9. Improving Rotor-Angle Stability via Virtual Inertia Planning for Converter-Interfaced Generations

      Jinpeng Guo, Chenpeng Chen, Xiaozhe Wang, Xueping Pan, Xiaorong Sun

      Abstract

      The virtual inertia control (VIC) of converter-interfaced generations (CIGs), which is originally applied to provide inertia support, will also affect system rotor-angle stability. This chapter proposes to control the virtual inertia constants coordinately such that sufficient inertia support is achieved, and meanwhile, the small signal rotor-angle stability can be enhanced without applying damping control strategies. Numerical studies in the IEEE 68 bus system have demonstrated that the proposed control strategy is effective enough.

   10. A Risk Assessment Model for the Impact of Insufficient Inertia on New Power Systems

       Sitong Liu, Siqing Huangfu, Yujie Qin, Yuchen Cao

       Abstract

       To achieve the dual carbon goal, China has decided to develop energetically clean energy and will develop a new energy system that uses low inertia to reduce carbon emissions. This new technology will have a significant impact on the security and stability of the system. In order to accurately identify system risks, this chapter presents an evaluation study on the influence of inertial errors on the risk of new power supply systems. An evaluation index system is constructed in three dimensions: the generation, load side, and energy storage side. To measure the evaluation results, the AHP method and the cloud model are selected. This suggests that inertial errors have a significant impact on the risk of new electrical systems.

   11. Research on Optimal Method of Reactive Power Compensation for Power Grid Based on Risk Assessment

       Jin Liu, Yuanting Hu, Zhiyang Liu, Xinghua Mu, Jun Zheng, Zexin Mu

       Abstract

       In this chapter, the algorithm is used to locate the weak link of the power system, and then the strategy of voltage and reactive power optimization in the low-voltage area is put forward. Under this strategy, the compensation degree can be located quickly, and the voltage can be optimized so that the coordination of reactive power compensation capacity and compensation position can be considered. Through the simulation analysis of the actual power grid, the control strategy proposed in this chapter has a good control effect on the regional voltage stability, and provides a guiding basis for the economic dispatching of the power grid.

   12. Analysis of the Characteristics of 10 kV Lightning Arrester Discharge Current Under Typical Lightning Strikes

       Xuefeng Wang, Minchuan Liao, Zibin Yu, Lu Qu, Feihong Diao, Hao Liu, Jian Wang, Hansheng Cai

       Abstract

       Analysis of the discharge current of lightning arresters under typical lightning strikes can be carried out to determine the aging test of the lightning arrester and accurate life assessment by providing a waveform basis. But also to identify different types of lightning strikes, and to carry out targeted lightning protection measures. In this chapter, a PSCAD electromagnetic transient simulation model is constructed for a practical double-circuit 10 kV cable-overhead transmission line-cable typical configuration. The monitoring range of the lightning arrester discharge current monitoring device on the terminal tower under various lightning strike types is analyzed, along with the impact of lightning current amplitude and strike location on the waveform of discharge current at the terminal tower arresters. Additionally, the range of discharge current waveforms at terminal tower arresters under different lightning strike types is statistically compiled. The work in this chapter will provide a database for lightning arrester aging tests and lightning strike type identification.

   13. Research on the Application of Domestic Modeling and Simulation Platform in Nuclear Power Plants

       Xingang Guo, Yanjun Hu, Tian Wan, Shengzhi Liu, Ying Xu

       Abstract

       Nuclear power plants involve numerous systems and equipment, complex system processes, and strict operating conditions. More technical problems in the field cannot be tested and verified directly on the unit, and the cost and price of offline physical experiments are also higher, which is not conducive to the analysis of the root cause of the problem and to determining the solution. The computational modeling simulation technology in the creation of numerical models and the simulation of the problem simulation and so on has more advantages. Early mainstream modeling and simulation platforms are mostly imported from abroad, such as MATLAB and Simulink. With the continuous maturity and wide application of domestic modeling and simulation platforms, they are increasingly used in aerospace, ship, vehicle, nuclear energy, and other fields. The chapter introduces the typical application of the MWorks domestic modeling and simulation platform in some nuclear power plants to introduce the basic usage and precautions of the platform in the analysis of on-site problems and formulation of solutions in the field of technological retrofit.

   14. Optimization of Active Distribution Network Scheduling Based on Stackelberg Game

       Dewen Kong, Ruijin Zhu, Zixuan Liu, Hao Guo

       Abstract

       To enhance the stability and economic efficiency of power distribution systems with high penetration of renewable energy sources, this paper proposes an optimization model for active distribution network scheduling based on Stackelberg game theory. By utilizing the Stackelberg relationship between the active distribution network and the load aggregator (LA), a day-ahead game model is established to achieve peak shaving and valley filling in the distribution network while considering the economic interests of both master and slave. The feasibility of the proposed model is verified through case study analysis.

   15. Current Situation and Prospect of Impedance Spectroscopy and Its Application in Electric Power Equipment Oil’s Performance Test

       Hongquan Li, Gang Xiong, Yan Chen

       Abstract

       For oil-consuming electric power equipment, their protection and condition monitoring are dependent on the real-time test of its oil’s various performance, for which impedance spectroscopy (IS) provides a potentially efficient technology. Therefore, the current situation and prospect of IS and its application in Electric Power Equipment Oil (EPEO)’s performance test are reviewed in this paper. First, IS is introduced from new classifications of univariate IS and multivariate IS, the current problems in EPEO’s performance test are summarized, and for solutions to these problems, the principle of why a matter system’s various properties can be tested by IS and IS’s advantages and application potentials are analyzed. Then, IS’s development status in impedance spectrum’s measurement and acquisition, analysis and processing, and industrial application is summarized, and its implementation scheme and key problems in EPEO’s performance test, including the construction of impedance spectrum’s measuring system, the analysis and processing of spectrum data, and the representation and derivation of EPEO’s performance, are also provided. Finally, it is pointed out that (1) the pursuit of high-precision, rapid, miniaturized, and multivariate impedance spectrum measuring technology and instruments; (2) for impedance spectrum analysis and processing, the mining of in-depth information, construction of new object models, processing of the impedance spectrum under nonlinear or even unstable conditions, and the analysis of multivariate impedance spectra; (3) the development of industrial applications in depth and breadth are IS’s future trends.

   16. A Fault Rate Evaluation Model of Distribution Network Line Under Wind and Rain Hazards

       Shaofeng Yu, Zhaobin Zhu, Jiasheng Peng, Wei Guo, Bozheng Wu

       Abstract

       In recent years, with the impact of human activities on the natural environment and the periodic change of global climate, the number of extreme natural disasters such as typhoons, ice and snow, and earthquakes has been increasing. This study introduces a fault rate assessment model of distribution network lines based on equipment health under wind and rain disasters, which includes the following steps: First, the stress of distribution network wires and pylons under typhoon and rainstorm is analyzed, and the failure rate model of wires under typhoon rainstorm disaster is obtained based on the pressure of wires. Then, the failure rate evaluation model of the distribution network line with equipment health is obtained by combining the failure rate model of typhoon, rainstorm, and equipment health. Finally, a case is given to verify the effectiveness of the proposed model.

   17. Voltage Fluctuation Solution and Control Strategy of Traction Network Based on Vehicle Energy Storage

       Zhaolong Ren, Mingxing Tian

       Abstract

       Aiming at the impact of traction network voltage on high-speed railways operating under different conditions, such as traction and braking, resulting in the rise and fall of traction network voltage, which has a negative impact on the safe running of trains, a traction network active power and harmonic current compensation control strategy based on on-board energy storage is proposed. It can effectively suppress the voltage fluctuation of the traction network caused by different operating conditions. The regenerative braking energy is greatly utilized and suppresses harmonic overvoltage. Firstly, the topology circuit of the vehicle energy storage system is established, and the operating mode of the system is analyzed. Then, two kinds of network pressure fluctuation mechanisms are analyzed, and the compensation principle is studied. Secondly, the method of voltage fluctuation compensation of the traction network and its system topology is proposed. Finally, the feasibility and correctness of the scheme are tested through the establishment of a simulation. This method can effectively suppress voltage fluctuations in traction networks under different conditions, as well as harmonic currents.

   18. Research on Distributed Optimal Scheduling Technology for Distribution Networks with High-Proportion Photovoltaic Integration

       Zhitao Tang, Xiuqing Lin, Keying Huang, Juntao Pan

       Abstract

       Traditional centralized optimal scheduling faces issues such as complex control, low reliability, and information privacy. Compared to centralized control, distributed control has advantages such as greater flexibility and reliability. Therefore, this paper proposes a distributed optimal scheduling strategy for distribution networks with high-proportion photovoltaic (PV) integration. Firstly, based on the modularity index and cluster self-consumption capacity index, the genetic algorithm is used to partition the distribution network clusters. Then, aiming at minimizing network loss costs and curtailment costs, a distributed optimal scheduling model for the distribution network is established and solved using the alternating direction method of multipliers (ADMM). Finally, using the IEEE 33-node distribution system as an example for simulation verification, the proposed strategy can effectively enhance the PV consumption capacity of the distribution network, reduce system network losses, and improve the power quality of the system.

   19. Research on the Application of Magnetic Network Approach in Magnetically Saturated Controllable Reactors

       Yuexin Li, Mingxing Tian

       Abstract

       In the preliminary design calculation of the magnetically saturated controllable reactor (MSCR), the finite element simulation, although the accuracy meets the requirements, the complexity of the model is more complicated, and the time spent is costly. By observing the magnetic field distribution of the finite element model and considering the structural characteristics of the MSCR, the mesh is dissected, and the equivalent flux tube method is used to establish a magnetic network model considering the magnetic leakage effect. Based on the similarity between the magnetic network and the electric network, the nodal method is used to establish the nodal magnetic potential equation for solving, and the operating current of the MSCR can be obtained from Kirchhoff's law of magnetic potential and Ampere's law of loop.

   20. A Parallel 18-Pulse Rectifier Based on Power Electronic Transformer

       Jiangyun Gong, Xiaoqiang Chen, Tun Bai, Ying Wang

       Abstract

       In order to solve the problem of large volume and high weight of phase shifting transformers, which are necessary components in multi-pulse rectifiers. A parallel 18-pulse rectifier based on an electrical and electronic transformer is proposed, consisting of an electrical and electronic converter and a high-frequency multi-pulse rectifier. By using an electrical and electronic converter, the AC power frequency can be converted to a high frequency. Then, the phase-shifted through a phase transformer to form three sets of three-phase rectifier bridges for rectification. This chapter studies the working principle of power electronic transformers and formulates management strategies based on their working principle. After analysis, the coupling between input and output voltages of power electronic transformers is obtained through the operating mode under high-frequency conditions of rectifier bridges. The simulation results show that replacing traditional power frequency transformers with electronic transformers reduces the transformer volume by two-thirds, ensuring stable power quality and confirming the feasibility and accuracy of the theoretical analysis.

   21. Splitting and Modularized Combination Approach of Power Distribution Terminal Services for Microservices Architecture

       Junye Li, Tiantian Cai, Xuhui Wang, Ming Hu, Xiaohua Li, Zexiang Cai, Xuran Liang, Bin Yang

       Abstract

       Aiming at the challenges of tightly coupled and difficult-to-change business applications of power information terminals of new power systems, this chapter proposes a microservice-oriented business disassembly and combination method for power distribution terminals. First, the electric power business organization process is portrayed in the form of electric power functional components by business, and the levels and types of electric power functional components are modeled to give the electric power business decomposition model. Then, the coupling model between functional components and component attributes is established, and based on which, the power business splitting constraints, power functional component performance evaluation indexes are given, and the business splitting is completed. At the same time, the open architecture is used to combine the functional components into modules with higher hierarchical granularity, and changes in the business requirements are localized to the specific modules to save development cost and cycle time, and to improve the scalability of the business applications. Finally, we analyze the impact of the splitting scheme and modular combination strategy on the coupling and scalability of electric power business applications through examples, and compare the solving effects of different architectures, so as to provide means and basis for analyzing the reasonable construction of organizational splitting and modular combination of electric power distribution terminal business.