The Device-to-Device(D2D)communication underlaying cellular networks is considered in this study.The D2D transmitter in the D2D mode can directly transmit messages to a receiver,but it may interfere with the transmiss...The Device-to-Device(D2D)communication underlaying cellular networks is considered in this study.The D2D transmitter in the D2D mode can directly transmit messages to a receiver,but it may interfere with the transmission of another cellular user who shares the same uplink channel.The transmitter can also operate in a cellular mode in which no interference to another cellular user occurs.We propose a mode selection scheme that aims to minimize the transmission power of the D2D transmitter subject to constraints on the minimum required data rate and maximum interference to other cellular users.The proposed scheme is based on bounds for transmission power and is less complex than the optimal scheme.Furthermore,it requires only a few statistics and does not need a fading channel distribution.The performance of the scheme is close to optimum when the number of Base Station(BS)antennas is large,and the mean absolute deviation of the fading terms is small.We verify this with numerical results of the Rician and Rayleigh fading channels by assuming that the BS antennas are independent.The simulation results for the two correlated BS antennas are presented herein.展开更多
With the rapid development of renewable energy,wind-thermal-bundled power transmission by line-commutated converter based high-voltage direct current(LCC-HVDC)systems has been widely developed.The dynamic interaction ...With the rapid development of renewable energy,wind-thermal-bundled power transmission by line-commutated converter based high-voltage direct current(LCC-HVDC)systems has been widely developed.The dynamic interaction mechanisms among permanent magnet synchronous generators(PMSGs),synchronous generators(SGs),and LCC-HVDC system become complex.To deal with this issue,a path analysis method(PAM)is proposed to study the dynamic interaction mechanism,and the damping reconstruction is used to analyze the damping characteristic of the system.First,based on the modular modeling,linearized models for the PMSG subsystem,the LCC-HVDC subsystem,and the SG subsystem are established.Second,based on the closed-loop transfer function diagram of the system,the disturbance transfer path and coupling relationship among subsystems are analyzed by the PAM,and the damping characteristic analysis of the SG-dominated oscillation mode is studied based on the damping reconstruction.Compared with the PAM,the small-signal model of the system is obtained and eigenvalue analysis results are presented.Then,the effect of the control parameters on the damping characteristic is analyzed and the conclusions are verified by time-domain simulations.Finally,the penalty functions of the oscillation modes and decay modes are taken as the objective function,and an optimization strategy based on the Monte Carlo method is proposed to solve the parameter optimization problem.Numerical simulation results are presented to validate the effectiveness of the proposed strategy.展开更多
The 10-GW-class Jiuquan Wind Power Base in Gansu Province is to get its Phase I Project completed soon, and will further expand and become the world largest wind power base in the future. Whether electricity from the ...The 10-GW-class Jiuquan Wind Power Base in Gansu Province is to get its Phase I Project completed soon, and will further expand and become the world largest wind power base in the future. Whether electricity from the wind power base can be delivered on such a large scale becomes the focus of attention of the world. This paper analyzes four challenges facing the wind power base, including transmission capability, peak regulation and frequency modulation, capacity balance and generation accommodation, as well as system stability.展开更多
远距离海上风电越来越多地选择柔性直流经海缆送出的方式。采用电缆的柔性直流(voltage source converter based high voltage direct current,VSC-HVDC)输电系统,其故障特性比传统架空线直流输电系统更加复杂。文中基于对称单极拓扑的...远距离海上风电越来越多地选择柔性直流经海缆送出的方式。采用电缆的柔性直流(voltage source converter based high voltage direct current,VSC-HVDC)输电系统,其故障特性比传统架空线直流输电系统更加复杂。文中基于对称单极拓扑的双端VSC-HVDC海上风电送出工程,简化了电缆和VSC-HVDC输电系统的数学模型,分析换流变阀侧交流系统单相接地和直流电缆线路单极接地等典型故障下的故障特性,运用叠加原理对故障机理进行解释;根据不同故障类型的故障源等效出不同的故障回路,得到了长距离电缆显著的电容效应对VSC-HVDC系统故障特征的复杂影响;利用实时数字仿真平台,搭建远海风电送出系统硬件在环仿真模型,验证了故障机理解析分析的正确性。展开更多
To reduce the probability of commutation failure(CF)of a line commutated converter based high-voltage direct current(LCC-HVDC)transmission,a DC chopper topology composed of power consumption sub-modules based on thyri...To reduce the probability of commutation failure(CF)of a line commutated converter based high-voltage direct current(LCC-HVDC)transmission,a DC chopper topology composed of power consumption sub-modules based on thyristor full-bridge module(TFB-PCSM)is proposed.Firstly,the mechanism of the proposed topology to mitigate CF is analyzed,and the working modes of TFB-PCSM in different operation states are introduced.Secondly,the coordinated control strategy between the proposed DC chopper and LCC-HVDC is designed,and the voltage-current stresses of the TFB-PCSMs are investigated.Finally,the ability to mitigate the CF issues and the fault recovery performance of LCC-HVDC system are studied in PSCAD/EMTDC.The results show that the probability of CF of LCC-HVDC is significantly reduced,and the performances of fault recovery are effectively improved by the proposed DC chopper.展开更多
基金This work was supported by Kasetsart University Research and Development Institute(KURDI)under the FY2016 Kasetsart University research grant,and the Royal Golden Jubilee Ph.D.program.
文摘The Device-to-Device(D2D)communication underlaying cellular networks is considered in this study.The D2D transmitter in the D2D mode can directly transmit messages to a receiver,but it may interfere with the transmission of another cellular user who shares the same uplink channel.The transmitter can also operate in a cellular mode in which no interference to another cellular user occurs.We propose a mode selection scheme that aims to minimize the transmission power of the D2D transmitter subject to constraints on the minimum required data rate and maximum interference to other cellular users.The proposed scheme is based on bounds for transmission power and is less complex than the optimal scheme.Furthermore,it requires only a few statistics and does not need a fading channel distribution.The performance of the scheme is close to optimum when the number of Base Station(BS)antennas is large,and the mean absolute deviation of the fading terms is small.We verify this with numerical results of the Rician and Rayleigh fading channels by assuming that the BS antennas are independent.The simulation results for the two correlated BS antennas are presented herein.
基金supported in part by the National Natural Science Foundation of China(No.U22B20109).
文摘With the rapid development of renewable energy,wind-thermal-bundled power transmission by line-commutated converter based high-voltage direct current(LCC-HVDC)systems has been widely developed.The dynamic interaction mechanisms among permanent magnet synchronous generators(PMSGs),synchronous generators(SGs),and LCC-HVDC system become complex.To deal with this issue,a path analysis method(PAM)is proposed to study the dynamic interaction mechanism,and the damping reconstruction is used to analyze the damping characteristic of the system.First,based on the modular modeling,linearized models for the PMSG subsystem,the LCC-HVDC subsystem,and the SG subsystem are established.Second,based on the closed-loop transfer function diagram of the system,the disturbance transfer path and coupling relationship among subsystems are analyzed by the PAM,and the damping characteristic analysis of the SG-dominated oscillation mode is studied based on the damping reconstruction.Compared with the PAM,the small-signal model of the system is obtained and eigenvalue analysis results are presented.Then,the effect of the control parameters on the damping characteristic is analyzed and the conclusions are verified by time-domain simulations.Finally,the penalty functions of the oscillation modes and decay modes are taken as the objective function,and an optimization strategy based on the Monte Carlo method is proposed to solve the parameter optimization problem.Numerical simulation results are presented to validate the effectiveness of the proposed strategy.
文摘The 10-GW-class Jiuquan Wind Power Base in Gansu Province is to get its Phase I Project completed soon, and will further expand and become the world largest wind power base in the future. Whether electricity from the wind power base can be delivered on such a large scale becomes the focus of attention of the world. This paper analyzes four challenges facing the wind power base, including transmission capability, peak regulation and frequency modulation, capacity balance and generation accommodation, as well as system stability.
文摘远距离海上风电越来越多地选择柔性直流经海缆送出的方式。采用电缆的柔性直流(voltage source converter based high voltage direct current,VSC-HVDC)输电系统,其故障特性比传统架空线直流输电系统更加复杂。文中基于对称单极拓扑的双端VSC-HVDC海上风电送出工程,简化了电缆和VSC-HVDC输电系统的数学模型,分析换流变阀侧交流系统单相接地和直流电缆线路单极接地等典型故障下的故障特性,运用叠加原理对故障机理进行解释;根据不同故障类型的故障源等效出不同的故障回路,得到了长距离电缆显著的电容效应对VSC-HVDC系统故障特征的复杂影响;利用实时数字仿真平台,搭建远海风电送出系统硬件在环仿真模型,验证了故障机理解析分析的正确性。
基金supported by National Natural Science Foundation of China(No.51877077)。
文摘To reduce the probability of commutation failure(CF)of a line commutated converter based high-voltage direct current(LCC-HVDC)transmission,a DC chopper topology composed of power consumption sub-modules based on thyristor full-bridge module(TFB-PCSM)is proposed.Firstly,the mechanism of the proposed topology to mitigate CF is analyzed,and the working modes of TFB-PCSM in different operation states are introduced.Secondly,the coordinated control strategy between the proposed DC chopper and LCC-HVDC is designed,and the voltage-current stresses of the TFB-PCSMs are investigated.Finally,the ability to mitigate the CF issues and the fault recovery performance of LCC-HVDC system are studied in PSCAD/EMTDC.The results show that the probability of CF of LCC-HVDC is significantly reduced,and the performances of fault recovery are effectively improved by the proposed DC chopper.
