The Experts below are selected from a list of 183453 Experts worldwide ranked by ideXlab platform
Frede Blaabjerg - One of the best experts on this subject based on the ideXlab platform.
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state space modeling techniques of emerging grid connected converters
Energies, 2020Co-Authors: Fabio Mandrile, S Musumeci, Enrico Carpaneto, R Bojoi, Tomislav Dragicevic, Frede BlaabjergAbstract:In modern power electronics-based power systems, accurate modeling is necessary in order to analyze stability and the interaction between the different elements, which are connected to it. State space modeling seems a valid approach to study the modes of a certain system and their correlation with its states. Unfortunately, this approach may require complicated calculations and it is difficult to model advanced or emerging control techniques for grid-tied converters, such as cascaded controllers (e.g., voltage and current) and virtual synchronous generators (VSGs). Moreover, this approach does not allow an easy reconfiguration of the modeled system by adding, removing of modifying certain elements. To solve such problems, this paper presents a step-by-step approach to the converter modeling based on the Component Connection Method (CCM). The CCM is explained in detail and a practical example is given, by modeling one exemplary VSG model available in the literature. The obtained model is finally validated experimentally to demonstrate the practical accuracy of such approach.
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A Hybrid Cable Connection Structure for Wind Farms With Reliability Consideration
IEEE Access, 2019Co-Authors: Junxian Li, Weihao Hu, Xiawei Wu, Qi Huang, Zhou Liu, Zhe Chen, Frede BlaabjergAbstract:The collector system in wind farm has a large number of cables. When one of the cable fails, the power generated by the wind turbine (WT) cannot be collected into the substation through the faulty cable. That would make the profits for the wind farm reduced. Therefore, it is necessary to find a more reliable cable structure, which can transfer power as much as possible even if the cable failure occurs. In this paper, a new cable Connection Method is proposed in two main steps to improve both the reliability of the cable Connection and the economic. Two different wind farms with the same climatological information and high voltage substation location are investigated and compared in the case study. In the first step, the minimum spanning tree (MST) algorithm is adopted to connect all wind turbines (WTs) to the substation. The cables used in collector system are the 33-kV middle voltage alternating current (MVAC) cables. Then the power production generated by WTs is transmitted from substation to the high voltage substation via a 132-kV transmission cable. The initial cable Connection layout is obtained in the first step and the total trenching length is optimized to be minimum. In addition, cable selection in each branch can be determined based on the cable current carrying capacity. In the second step, reliability assessment is implemented by analyzing the expected energy not supplied (EENS). Based on EENS, the evaluation index ${LPC}_{rel}$ is obtained. This index takes both reliability and economy into account. Additional cables found by particle swarm optimization (PSO) algorithm are added to the initial cable Connection layout. Finally, a cable layout called hybrid structure is formed. What is more, by adding additional cables, the ${LPC}_{rel}$ is reduced by 1.5%. The simulation results clearly indicate that the proposed Method is better when the cable failure is considered.
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small signal stability analysis of inverter fed power systems using component Connection Method
IEEE Transactions on Smart Grid, 2018Co-Authors: Yanbo Wang, Zhe Chen, Xiongfei Wang, Frede BlaabjergAbstract:The small time constants of power electronics devices lead to dynamic couplings with the electromagnetic transients of power networks, and thus complicate the modeling and stability analysis of power-electronics-based power systems. This paper presents a computationally efficient approach to assess the small-signal stability of inverter-fed power systems. The power system is partitioned into individual components, including the power inverters, network impedances, and power loads. The state-space model of individual inverter is first built, where the frequency response and eigenvalue analysis collectively characterize the contributions of different controller parameters to the terminal behavior in a wide frequency range. These component models, together with the network equations, are then algebraically assembled based on the interConnection relations at their terminals. As a consequence, the state matrix of the whole system, which is essential to the system stability analysis, can be reformulated in a computationally efficient way. The experimental results are finally given to validate the effectiveness of the modeling Method and system stability analysis.
Zhe Chen - One of the best experts on this subject based on the ideXlab platform.
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small signal modelling of ac mtdc hybrid power systems using multi layer component Connection Method
Energy Reports, 2020Co-Authors: Guozhou Zhang, Hao Wang, Yuanhong Tang, Shi Jing, Zhe ChenAbstract:Abstract In order to simplify the stability analysis of an AC/MTDC (multi-terminal direct current) power system, this paper presents a Multi-Layer Component Connection Method (MLCCM)-based small signal model for AC/MTDC hybrid power systems. Based on ML-CCM, the system is partitioned as small individual system or components, including generator units, voltage source converter (VSC) units, time delay units, AC network and DC network. The modelling procedure can be 3 steps. First, the individual components are independently modelled. Second, several small individual components are assembled together to build the AC system model based on component interConnection relationship. Third, all AC power systems and DC network model are assembled together to build the whole hybrid power based on the interConnection relationship. There are three features for the MLCCM: (1) these component models can be built individually; (2) their interConnection relationship is a linear algebra matrix; (3) subsystem model can be verified or debugged individually. Due to the three features, the whole hybrid power can be built easily and it is convenient for finding modelling fault and debugging. An AC/DC hybrid system model in MATLAB/Simulink is also built to validate the effectiveness of the MLCCM-based small signal model.
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A Hybrid Cable Connection Structure for Wind Farms With Reliability Consideration
IEEE Access, 2019Co-Authors: Junxian Li, Weihao Hu, Xiawei Wu, Qi Huang, Zhou Liu, Zhe Chen, Frede BlaabjergAbstract:The collector system in wind farm has a large number of cables. When one of the cable fails, the power generated by the wind turbine (WT) cannot be collected into the substation through the faulty cable. That would make the profits for the wind farm reduced. Therefore, it is necessary to find a more reliable cable structure, which can transfer power as much as possible even if the cable failure occurs. In this paper, a new cable Connection Method is proposed in two main steps to improve both the reliability of the cable Connection and the economic. Two different wind farms with the same climatological information and high voltage substation location are investigated and compared in the case study. In the first step, the minimum spanning tree (MST) algorithm is adopted to connect all wind turbines (WTs) to the substation. The cables used in collector system are the 33-kV middle voltage alternating current (MVAC) cables. Then the power production generated by WTs is transmitted from substation to the high voltage substation via a 132-kV transmission cable. The initial cable Connection layout is obtained in the first step and the total trenching length is optimized to be minimum. In addition, cable selection in each branch can be determined based on the cable current carrying capacity. In the second step, reliability assessment is implemented by analyzing the expected energy not supplied (EENS). Based on EENS, the evaluation index ${LPC}_{rel}$ is obtained. This index takes both reliability and economy into account. Additional cables found by particle swarm optimization (PSO) algorithm are added to the initial cable Connection layout. Finally, a cable layout called hybrid structure is formed. What is more, by adding additional cables, the ${LPC}_{rel}$ is reduced by 1.5%. The simulation results clearly indicate that the proposed Method is better when the cable failure is considered.
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small signal stability analysis of inverter fed power systems using component Connection Method
IEEE Transactions on Smart Grid, 2018Co-Authors: Yanbo Wang, Zhe Chen, Xiongfei Wang, Frede BlaabjergAbstract:The small time constants of power electronics devices lead to dynamic couplings with the electromagnetic transients of power networks, and thus complicate the modeling and stability analysis of power-electronics-based power systems. This paper presents a computationally efficient approach to assess the small-signal stability of inverter-fed power systems. The power system is partitioned into individual components, including the power inverters, network impedances, and power loads. The state-space model of individual inverter is first built, where the frequency response and eigenvalue analysis collectively characterize the contributions of different controller parameters to the terminal behavior in a wide frequency range. These component models, together with the network equations, are then algebraically assembled based on the interConnection relations at their terminals. As a consequence, the state matrix of the whole system, which is essential to the system stability analysis, can be reformulated in a computationally efficient way. The experimental results are finally given to validate the effectiveness of the modeling Method and system stability analysis.
Chiaming Uang - One of the best experts on this subject based on the ideXlab platform.
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effects of panel zone strength and beam web Connection Method on seismic performance of reduced beam section steel moment Connections
Journal of Structural Engineering-asce, 2005Co-Authors: Sangwoo Jeon, Chiaming UangAbstract:This paper presents test results on eight reduced beam section (RBS) steel moment Connections. The testing program addressed web Connection type (bolted versus welded) and panel zone (PZ) strength as the key variables. Specimens with medium PZ strength were designed to promote energy dissipation from both PZ and RBS regions such that expensive doubler plates were not needed. Both strong and medium PZ specimens with a welded web Connection were able to provide satisfactory Connection rotation capacity for special moment-resisting frames. However, specimens with a bolted web Connection performed poorly due to premature brittle fracture of the beam flange at the weld access hole. A plausible explanation for the higher incidence of base metal fracture in bolted web specimens was presented based on the measured strain data. Test results from this study and by others showed that panel zones could easily develop a plastic rotation of 0.01 rad without causing distress to the beam flange groove welds. At this deformation level, the amount of beam distortion (i.e., buckling) was about one half that developed in strong PZ specimens. A criterion for a balanced PZ strength that improves the plastic rotation capacity while reducing the amount of beam buckling is proposed.
Yanbo Wang - One of the best experts on this subject based on the ideXlab platform.
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small signal stability analysis of inverter fed power systems using component Connection Method
IEEE Transactions on Smart Grid, 2018Co-Authors: Yanbo Wang, Zhe Chen, Xiongfei Wang, Frede BlaabjergAbstract:The small time constants of power electronics devices lead to dynamic couplings with the electromagnetic transients of power networks, and thus complicate the modeling and stability analysis of power-electronics-based power systems. This paper presents a computationally efficient approach to assess the small-signal stability of inverter-fed power systems. The power system is partitioned into individual components, including the power inverters, network impedances, and power loads. The state-space model of individual inverter is first built, where the frequency response and eigenvalue analysis collectively characterize the contributions of different controller parameters to the terminal behavior in a wide frequency range. These component models, together with the network equations, are then algebraically assembled based on the interConnection relations at their terminals. As a consequence, the state matrix of the whole system, which is essential to the system stability analysis, can be reformulated in a computationally efficient way. The experimental results are finally given to validate the effectiveness of the modeling Method and system stability analysis.
Hao Wang - One of the best experts on this subject based on the ideXlab platform.
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small signal modelling of ac mtdc hybrid power systems using multi layer component Connection Method
Energy Reports, 2020Co-Authors: Guozhou Zhang, Hao Wang, Yuanhong Tang, Shi Jing, Zhe ChenAbstract:Abstract In order to simplify the stability analysis of an AC/MTDC (multi-terminal direct current) power system, this paper presents a Multi-Layer Component Connection Method (MLCCM)-based small signal model for AC/MTDC hybrid power systems. Based on ML-CCM, the system is partitioned as small individual system or components, including generator units, voltage source converter (VSC) units, time delay units, AC network and DC network. The modelling procedure can be 3 steps. First, the individual components are independently modelled. Second, several small individual components are assembled together to build the AC system model based on component interConnection relationship. Third, all AC power systems and DC network model are assembled together to build the whole hybrid power based on the interConnection relationship. There are three features for the MLCCM: (1) these component models can be built individually; (2) their interConnection relationship is a linear algebra matrix; (3) subsystem model can be verified or debugged individually. Due to the three features, the whole hybrid power can be built easily and it is convenient for finding modelling fault and debugging. An AC/DC hybrid system model in MATLAB/Simulink is also built to validate the effectiveness of the MLCCM-based small signal model.