The liquid metal current limiter(LMCL)is regarded as a viable solution for reducing the fault current in a power grid.But demonstrating the liquid metal arc plasma self-pinching process of the resistive wall,and reduc...The liquid metal current limiter(LMCL)is regarded as a viable solution for reducing the fault current in a power grid.But demonstrating the liquid metal arc plasma self-pinching process of the resistive wall,and reducing the erosion of the LMCL are challenging,not only theoretically,but also practically.In this work,a novel LMCL is designed with a resistive wall that can be connected to the current-limiting circuit inside the cavity.Specifically,a novel fault current limiter(FCL)topology is put forward where the novel LMCL is combined with a fast switch and current-limiting reactor.Further,the liquid metal self-pinch effect is modeled mathematically in three dimensions,and the gas-liquid two-phase dynamic diagrams under different short-circuit currents are obtained by simulation.The simulation results indicate that with the increase of current,the time for the liquid metal-free surface to begin depressing is reduced,and the position of the depression also changes.Different kinds of bubbles formed by the depressions gradually extend,squeeze,and break.With the increase of current,the liquid metal takes less time to break,but breaks still occur at the edge of the channel,forming arc plasma.Finally,relevant experiments are conducted for the novel FCL topology.The arcing process and current transfer process are analyzed in particular.Comparisons of the peak arc voltage,arcing time,current limiting efficiency,and electrode erosion are presented.The results demonstrate that the arc voltage of the novel FCL topology is reduced by more than 4.5times and the arcing time is reduced by more than 12%.The erosions of the liquid metal and electrodes are reduced.Moreover,the current limiting efficiency of the novel FCL topology is improved by 1%–5%.This work lays a foundation for the topology and optimal design of the LMCL.展开更多
The fault current limiter(FCL)is an effective measure for improving system stability and suppressing short-circuit fault current.Because of space and economic costs,the optimum placement of FCLs is vital in industrial...The fault current limiter(FCL)is an effective measure for improving system stability and suppressing short-circuit fault current.Because of space and economic costs,the optimum placement of FCLs is vital in industrial applications.In this study,two objectives with the same dimensional measurement unit,namely,the total capital investment cost of FCLs and circuit breaker loss related to short-circuit currents,are considered.The circuit breaker loss model is developed based on the attenuation rule of the circuit breaker service life.The circuit breaker loss is used to quantify the current-limiting effect to avoid the problem of weight selection in a multi-objective problem.The IEEE 10-generator 39-bus system in New England is used to evaluate the performance of the proposed genetic algorithm(GA)method.Comparative and sensitivity analyses are performed.The results of the optimized plan are validated through simulations,indicating the significant potential of the GA for such optimization.展开更多
---For a saturated iron core fault current limiter, superconductor is the only suitable material to make the dc bias coil, especially when the device is used in a high voltage power grid. Commonly, superconducting wir...---For a saturated iron core fault current limiter, superconductor is the only suitable material to make the dc bias coil, especially when the device is used in a high voltage power grid. Commonly, superconducting wires are used to wind the dc bias coil Since the performance of the wires changes greatly under magnetic fields, the calculation of the field spatial distraction is essential to the optimization of the superconducting magnet. A superconducting coil with 141000 ampere-turns magnetizing capacity made of 17600 meters of BSCCO 2223 HTS tapes was fabricated. This coil was built for a 35 kV/90 MVA saturated iron-core fault current limiter. Computer simulations on magnetic field distribution were carried out to optimize the structural design, and experiments were done to verify the performance of the coil The configuration and the key parameters of the coil will be reported in this paper.展开更多
提出了一种故障限流器(Fault Current Limiter,FCL)的全局优化配置算法。FCL在电网正常情况下等效阻抗接近于0,且对电网无不利影响,短路故障时迅速增大等效阻抗限制短路电流,从而确保断路器可靠开断短路电流。FCL的配置是在满足限制短...提出了一种故障限流器(Fault Current Limiter,FCL)的全局优化配置算法。FCL在电网正常情况下等效阻抗接近于0,且对电网无不利影响,短路故障时迅速增大等效阻抗限制短路电流,从而确保断路器可靠开断短路电流。FCL的配置是在满足限制短路电流的前提下,使得加装FCL的数量和阻抗值最小,同时保证系统正常运行。通过进行短路计算,首先确定安装FCL能够可靠启动的支路,应用支路追加法形成导纳矩阵。基于PSO算法对候选支路进行优化选择,通过FCL的启动条件缩小搜索范围,实现FCL的安装位置、数量以及阻抗值的优化配置。最后,应用该算法对湖南电网2015规划数据进行了计算分析,得出了相应的FCL的优化配置方案。展开更多
混合式高压直流断路器分断速度快且通态损耗低,能够保证不闭锁换流站的情况下实现线路故障的快速隔离,减小故障范围,是直流电网保护的关键设备之一。首先研究了含混合式直流断路器的柔直系统直流故障限流机理,分析影响直流故障电流峰值...混合式高压直流断路器分断速度快且通态损耗低,能够保证不闭锁换流站的情况下实现线路故障的快速隔离,减小故障范围,是直流电网保护的关键设备之一。首先研究了含混合式直流断路器的柔直系统直流故障限流机理,分析影响直流故障电流峰值以及故障电流持续时间的关键因素,并在现有混合式高压直流断路器基础上,提出一种快速限流的优化技术方案,在转移支路加入故障限流子模块(fault current limiter submodule,FCL_SM),FCL_SM由二极管桥、限流电阻以及限压电路组成,通过在故障过程中投入FCL_SM来降低故障电流峰值以及MOV吸收能量。最后通过PSCAD/EMTDC仿真分析,验证了所提优化方案的可行性与有效性。仿真结果表明,优化方案可有效降低直流故障电流峰值(降低幅度达14%)、故障电流持续时间以及直流断路器MOV吸收能量(降低幅度达16.2%),并可有效降低设备设计成本。展开更多
基金supported by National Natural Science Foundation of China(Nos.51777025,52177131)the Interdisciplinary Program of the Wuhan National High Magnetic Field Center(No.WHMFC202130)Huazhong University of Science and Technology。
文摘The liquid metal current limiter(LMCL)is regarded as a viable solution for reducing the fault current in a power grid.But demonstrating the liquid metal arc plasma self-pinching process of the resistive wall,and reducing the erosion of the LMCL are challenging,not only theoretically,but also practically.In this work,a novel LMCL is designed with a resistive wall that can be connected to the current-limiting circuit inside the cavity.Specifically,a novel fault current limiter(FCL)topology is put forward where the novel LMCL is combined with a fast switch and current-limiting reactor.Further,the liquid metal self-pinch effect is modeled mathematically in three dimensions,and the gas-liquid two-phase dynamic diagrams under different short-circuit currents are obtained by simulation.The simulation results indicate that with the increase of current,the time for the liquid metal-free surface to begin depressing is reduced,and the position of the depression also changes.Different kinds of bubbles formed by the depressions gradually extend,squeeze,and break.With the increase of current,the liquid metal takes less time to break,but breaks still occur at the edge of the channel,forming arc plasma.Finally,relevant experiments are conducted for the novel FCL topology.The arcing process and current transfer process are analyzed in particular.Comparisons of the peak arc voltage,arcing time,current limiting efficiency,and electrode erosion are presented.The results demonstrate that the arc voltage of the novel FCL topology is reduced by more than 4.5times and the arcing time is reduced by more than 12%.The erosions of the liquid metal and electrodes are reduced.Moreover,the current limiting efficiency of the novel FCL topology is improved by 1%–5%.This work lays a foundation for the topology and optimal design of the LMCL.
基金supported by State Grid Science and Technology Projects(SGTYHT/17-JS-199)National Natural Science Foundation of China(51577163).
文摘The fault current limiter(FCL)is an effective measure for improving system stability and suppressing short-circuit fault current.Because of space and economic costs,the optimum placement of FCLs is vital in industrial applications.In this study,two objectives with the same dimensional measurement unit,namely,the total capital investment cost of FCLs and circuit breaker loss related to short-circuit currents,are considered.The circuit breaker loss model is developed based on the attenuation rule of the circuit breaker service life.The circuit breaker loss is used to quantify the current-limiting effect to avoid the problem of weight selection in a multi-objective problem.The IEEE 10-generator 39-bus system in New England is used to evaluate the performance of the proposed genetic algorithm(GA)method.Comparative and sensitivity analyses are performed.The results of the optimized plan are validated through simulations,indicating the significant potential of the GA for such optimization.
基金This work was supported by the Chinese Ministry of Science and Technology under Grant No. 2006AA03Z234Tianjin Municipal Science and Technology Commission under Grant No. 05FZZDGX00700Yunnan Provincial Science and Technology Department under Grant No. 2005GG07.
文摘---For a saturated iron core fault current limiter, superconductor is the only suitable material to make the dc bias coil, especially when the device is used in a high voltage power grid. Commonly, superconducting wires are used to wind the dc bias coil Since the performance of the wires changes greatly under magnetic fields, the calculation of the field spatial distraction is essential to the optimization of the superconducting magnet. A superconducting coil with 141000 ampere-turns magnetizing capacity made of 17600 meters of BSCCO 2223 HTS tapes was fabricated. This coil was built for a 35 kV/90 MVA saturated iron-core fault current limiter. Computer simulations on magnetic field distribution were carried out to optimize the structural design, and experiments were done to verify the performance of the coil The configuration and the key parameters of the coil will be reported in this paper.
文摘提出了一种故障限流器(Fault Current Limiter,FCL)的全局优化配置算法。FCL在电网正常情况下等效阻抗接近于0,且对电网无不利影响,短路故障时迅速增大等效阻抗限制短路电流,从而确保断路器可靠开断短路电流。FCL的配置是在满足限制短路电流的前提下,使得加装FCL的数量和阻抗值最小,同时保证系统正常运行。通过进行短路计算,首先确定安装FCL能够可靠启动的支路,应用支路追加法形成导纳矩阵。基于PSO算法对候选支路进行优化选择,通过FCL的启动条件缩小搜索范围,实现FCL的安装位置、数量以及阻抗值的优化配置。最后,应用该算法对湖南电网2015规划数据进行了计算分析,得出了相应的FCL的优化配置方案。
文摘混合式高压直流断路器分断速度快且通态损耗低,能够保证不闭锁换流站的情况下实现线路故障的快速隔离,减小故障范围,是直流电网保护的关键设备之一。首先研究了含混合式直流断路器的柔直系统直流故障限流机理,分析影响直流故障电流峰值以及故障电流持续时间的关键因素,并在现有混合式高压直流断路器基础上,提出一种快速限流的优化技术方案,在转移支路加入故障限流子模块(fault current limiter submodule,FCL_SM),FCL_SM由二极管桥、限流电阻以及限压电路组成,通过在故障过程中投入FCL_SM来降低故障电流峰值以及MOV吸收能量。最后通过PSCAD/EMTDC仿真分析,验证了所提优化方案的可行性与有效性。仿真结果表明,优化方案可有效降低直流故障电流峰值(降低幅度达14%)、故障电流持续时间以及直流断路器MOV吸收能量(降低幅度达16.2%),并可有效降低设备设计成本。
