In order to improve the voltage quality of rural power distribution network, the series capacitor in distribution lines is proposed. The principle of series capacitor compensation technology to improve the quality of ...In order to improve the voltage quality of rural power distribution network, the series capacitor in distribution lines is proposed. The principle of series capacitor compensation technology to improve the quality of rural power distribution lines voltage is analyzed. The real rural power distribution network simulation model is established by Power System Power System Analysis Software Package (PSASP). Simulation analysis the effect of series capacitor compensation technology to improve the voltage quality of rural power distribution network, The simulation results show that the series capacitor compensation can effectively improve the voltage quality and reduce network losses and improve the transmission capacity of rural power distribution network.展开更多
The large variability in wind output power can adversely impact local loads that are sensitive to poor power quality. To mitigate large swings in power, the wind turbine output power can be conditioned by using a smal...The large variability in wind output power can adversely impact local loads that are sensitive to poor power quality. To mitigate large swings in power, the wind turbine output power can be conditioned by using a small energy buffer. A power conditioner is developed to smooth the wind power output by utilizing the energy of an electrochemical capacitor, or ultracapacitor. The conditioner is based on a single phase voltage source inverter connected between the grid inter-connection point and the ultracapacitor. The VSI shunt inverter injects or absorbs active power from the line to smooth the wind power output by utilizing the short term storage capabilities of the ultracapacitor. The ultracapacitor is connected to the DC link through a bidirectional DC-DC converter. The bidirectional DC-DC converter and VSI are constructed and field tested on a Skystream 3.7 wind turbine installed at the Missouri University of Science & Technology.展开更多
In this paper, a mathematical analysis of the EMI (Electromagnetic Interference) for a 20 kHz/10 kV capacitor charging power supply in frequency-domain is presented, and a related circuit model considering the transie...In this paper, a mathematical analysis of the EMI (Electromagnetic Interference) for a 20 kHz/10 kV capacitor charging power supply in frequency-domain is presented, and a related circuit model considering the transient switching interference is proposed. Due to the high working frequency and the device-switching transitions, the conducted EMI caused by the charging circuit which includes the harmonics of grid frequency, working frequency and device-switching transition frequencies. Thus under certain working situations or loads parallel power supply, the interference may cause charging failure. To solve this problem, a high frequency transformer modeled with stray capacitances and an approximation of the device-switching transition is applied in the Spice-based simulation model, and a mathematical analysis in frequency-domain is presented.展开更多
Rechargeable aqueous zinc-ion hybrid capacitors and zincion batteries are promising safe energy storage systems.In this study,amorphous RuO2·H2O for the first time was employed to achieve fast and ultralong-life ...Rechargeable aqueous zinc-ion hybrid capacitors and zincion batteries are promising safe energy storage systems.In this study,amorphous RuO2·H2O for the first time was employed to achieve fast and ultralong-life Zn2+storage based on a pseudocapacitive storage mechanism.In the RuO2·H2O||Zn zinc-ion hybrid capacitors with Zn(CF3SO3)2 aqueous electrolyte,the RuO2·H2O cathode can reversibly store Zn2+in a voltage window of 0.4-1.6 V(vs.Zn/Zn2+),delivering a high discharge capacity of 122 mAh g?1.In particular,the zinc-ion hybrid capacitors can be rapidly charged/discharged within 36 s with a very high power density of 16.74 kW kg?1 and a high energy density of 82 Wh kg?1.Besides,the zinc-ion hybrid capacitors demonstrate an ultralong cycle life(over 10,000 charge/discharge cycles).The kinetic analysis elucidates that the ultrafast Zn2+storage in the RuO2·H2O cathode originates from redox pseudocapacitive reactions.This work could greatly facilitate the development of high-power and safe electrochemical energy storage.展开更多
The main purpose of the electrical power system is to transport and distribute energy generated by the central power plants in a safe and reliable manner to the customer premises. Most of the electrical equipment is e...The main purpose of the electrical power system is to transport and distribute energy generated by the central power plants in a safe and reliable manner to the customer premises. Most of the electrical equipment is exposed within the open which suggests they can be vulnerable to lightning strikes, road dwindling, windstorms, and a few engineering activities with the potential of causing different degrees of damage to the electrical equipment. One of the ways to guard the equipment is to deploy switching devices. However, the operations of most of these switching devices produce oscillatory transient in the electrical transmission and distribution systems which result in voltage, current, and frequency fluctuations in the load. This paper investigates the effect of switching devices on power quality and proposes a positive sequence voltage power transient suppression technique that can spontaneously improve the distorted voltage at the instant of capacitor switching using the capacitor line model as a case study. MATLAB/Simulink software was utilized for the analysis on an electrical network model with bus voltages of 69 kV/12.47 kV and 480 V. The results showed that, during switching operations, the positive sequence voltage power detector block produces ripple-free accurate results.展开更多
The global rise in energy demand, particularly in remote and sparsely populated regions, necessitates innovative and cost-effective electrical distribution solutions. Traditional Rural Electrification (RE) methods, li...The global rise in energy demand, particularly in remote and sparsely populated regions, necessitates innovative and cost-effective electrical distribution solutions. Traditional Rural Electrification (RE) methods, like Conventional Rural Electrification (CRE), have proven economically unfeasible in such areas due to high infrastructure costs and low electricity demand. Consequently, Unconventional Rural Electrification (URE) technologies, such as Capacitor Coupled Substations (CCS), are gaining attention as viable alternatives. This study presents the design and simulation of an 80 kW CCS system, which taps power directly from a 132 kV transmission line to supply low-voltage consumers. The critical components of the CCS, the capacitors are calculated, then a MATLAB/Simulink model with the attained results is executed. Mathematical representation and state-space representation for maintaining the desired tapped voltage area also developed. The research further explores the feasibility and operational performance of this CCS configuration, aiming to address the challenges of rural electrification by offering a sustainable and scalable solution. The results show that the desired value of the tapped voltage can be achieved at any level of High Voltage (HV) with the selection of capacitors that are correctly rated. With an adequately designed control strategy, the research also shows that tapped voltage can be attained under both steady-state and dynamic loads. By leveraging CCS technology, the study demonstrates the potential for delivering reliable electricity to underserved areas, highlighting the system’s practicality and effectiveness in overcoming the limitations of conventional distribution methods.展开更多
新型电力系统和智能电网储能技术是实现“降碳、减排、节能”目标的重要路径,也是发展绿色经济和清洁能源的重要举措.对地铁列车能量调度及其制动能量回收与储存展开研究.首先,分析了超级电容器组和蓄电池组件混合储能技术原理和结构特...新型电力系统和智能电网储能技术是实现“降碳、减排、节能”目标的重要路径,也是发展绿色经济和清洁能源的重要举措.对地铁列车能量调度及其制动能量回收与储存展开研究.首先,分析了超级电容器组和蓄电池组件混合储能技术原理和结构特点.其次,改善列车制动能量回收率,加强荷电状态(State of Charge,SOC)调度过程的可控性和灵活性,为电能协同利用与回收提供安全运行保障和智能检测.实验与仿真结果表明,采用混合储能技术优化后的列车制动能量损失单位里程每小时降低2000 W,牵引网压电量回收率提升了15%,电流传输稳定效率提升8%,列车用电调度效率和SOC估算精准度分别提高了约10%和12%,有效验证该混合储能优化方案的可行性.展开更多
带脉冲功率负载的直流供电系统现已广泛应用于电动车、舰船及航空等领域。当脉冲负载发生突变时,整流发电机端电压会随之变化,对整个供电系统的稳定性造成负面影响,此时,滤波电容起到了关键作用。直流供电系统中的滤波电容通常采用电解...带脉冲功率负载的直流供电系统现已广泛应用于电动车、舰船及航空等领域。当脉冲负载发生突变时,整流发电机端电压会随之变化,对整个供电系统的稳定性造成负面影响,此时,滤波电容起到了关键作用。直流供电系统中的滤波电容通常采用电解电容。电解电容存在寄生参数等效串联电阻(equivalent series resistance,ESR),会引起输出电压波形畸变及电压大小的变化。为此,该文提出一种考虑滤波电容寄生参数ESR的双三相整流发电机带脉冲负载的瞬时电压计算方法。首先,建立考虑滤波电容寄生参数ESR的带脉冲功率负载的双三相整流发电机等效瞬态数学模型;其次,通过双三相整流发电机瞬态有限元仿真同负载突变实验进行对比,验证所提出的考虑滤波电容寄生参数ESR的双三相整流发电机等效模型负载突变的瞬时电压计算方法的必要性与可行性;最后,分析滤波电容C及其寄生参数ESR对双三相整流发电机直流侧电压的影响。结果表明,建立的等效模型具有较高的准确性,同时,表明考虑滤波电容寄生参数ESR对整流发电机直流测电压的研究对提高整个直流供电系统电能质量具有重要意义。展开更多
为了契合绿色可再生能源发展理念,自供电环境能量收集系统已逐渐成为替代传统电池的高效解决方案,可克服传统电池在重量、尺寸及循环寿命等方面的局限性。针对压电源的时变特性,设计了一种基于其特性的快速最大功率点跟踪(Maximum Power...为了契合绿色可再生能源发展理念,自供电环境能量收集系统已逐渐成为替代传统电池的高效解决方案,可克服传统电池在重量、尺寸及循环寿命等方面的局限性。针对压电源的时变特性,设计了一种基于其特性的快速最大功率点跟踪(Maximum Power Point Tracking,MPPT)电路架构。对压电源的阻抗特性进行分析,采用了基于快速开关电容采样的开路电压采样MPPT算法,有效实现跟踪精度和动态响应速度的协同优化。最后,基于0.18μm BCD工艺对电路进行设计,仿真结果表明:MPPT的跟踪时间为0.36 ms,最大追踪精度可达99.4%。展开更多
文摘In order to improve the voltage quality of rural power distribution network, the series capacitor in distribution lines is proposed. The principle of series capacitor compensation technology to improve the quality of rural power distribution lines voltage is analyzed. The real rural power distribution network simulation model is established by Power System Power System Analysis Software Package (PSASP). Simulation analysis the effect of series capacitor compensation technology to improve the voltage quality of rural power distribution network, The simulation results show that the series capacitor compensation can effectively improve the voltage quality and reduce network losses and improve the transmission capacity of rural power distribution network.
文摘The large variability in wind output power can adversely impact local loads that are sensitive to poor power quality. To mitigate large swings in power, the wind turbine output power can be conditioned by using a small energy buffer. A power conditioner is developed to smooth the wind power output by utilizing the energy of an electrochemical capacitor, or ultracapacitor. The conditioner is based on a single phase voltage source inverter connected between the grid inter-connection point and the ultracapacitor. The VSI shunt inverter injects or absorbs active power from the line to smooth the wind power output by utilizing the short term storage capabilities of the ultracapacitor. The ultracapacitor is connected to the DC link through a bidirectional DC-DC converter. The bidirectional DC-DC converter and VSI are constructed and field tested on a Skystream 3.7 wind turbine installed at the Missouri University of Science & Technology.
文摘In this paper, a mathematical analysis of the EMI (Electromagnetic Interference) for a 20 kHz/10 kV capacitor charging power supply in frequency-domain is presented, and a related circuit model considering the transient switching interference is proposed. Due to the high working frequency and the device-switching transitions, the conducted EMI caused by the charging circuit which includes the harmonics of grid frequency, working frequency and device-switching transition frequencies. Thus under certain working situations or loads parallel power supply, the interference may cause charging failure. To solve this problem, a high frequency transformer modeled with stray capacitances and an approximation of the device-switching transition is applied in the Spice-based simulation model, and a mathematical analysis in frequency-domain is presented.
基金the financial support by the Australian Research Council through the ARC Discovery projects(DP160104340 and DP170100436)Rail Manufacturing Cooperative Research Centre(RMCRC 1.1.1 and RMCRC 1.1.2 projects)+1 种基金financially supported by the International Science&Technology Cooperation Program of China(No.2016YFE0102200)Shenzhen Technical Plan Project(No.JCYJ20160301154114273).
文摘Rechargeable aqueous zinc-ion hybrid capacitors and zincion batteries are promising safe energy storage systems.In this study,amorphous RuO2·H2O for the first time was employed to achieve fast and ultralong-life Zn2+storage based on a pseudocapacitive storage mechanism.In the RuO2·H2O||Zn zinc-ion hybrid capacitors with Zn(CF3SO3)2 aqueous electrolyte,the RuO2·H2O cathode can reversibly store Zn2+in a voltage window of 0.4-1.6 V(vs.Zn/Zn2+),delivering a high discharge capacity of 122 mAh g?1.In particular,the zinc-ion hybrid capacitors can be rapidly charged/discharged within 36 s with a very high power density of 16.74 kW kg?1 and a high energy density of 82 Wh kg?1.Besides,the zinc-ion hybrid capacitors demonstrate an ultralong cycle life(over 10,000 charge/discharge cycles).The kinetic analysis elucidates that the ultrafast Zn2+storage in the RuO2·H2O cathode originates from redox pseudocapacitive reactions.This work could greatly facilitate the development of high-power and safe electrochemical energy storage.
文摘The main purpose of the electrical power system is to transport and distribute energy generated by the central power plants in a safe and reliable manner to the customer premises. Most of the electrical equipment is exposed within the open which suggests they can be vulnerable to lightning strikes, road dwindling, windstorms, and a few engineering activities with the potential of causing different degrees of damage to the electrical equipment. One of the ways to guard the equipment is to deploy switching devices. However, the operations of most of these switching devices produce oscillatory transient in the electrical transmission and distribution systems which result in voltage, current, and frequency fluctuations in the load. This paper investigates the effect of switching devices on power quality and proposes a positive sequence voltage power transient suppression technique that can spontaneously improve the distorted voltage at the instant of capacitor switching using the capacitor line model as a case study. MATLAB/Simulink software was utilized for the analysis on an electrical network model with bus voltages of 69 kV/12.47 kV and 480 V. The results showed that, during switching operations, the positive sequence voltage power detector block produces ripple-free accurate results.
文摘The global rise in energy demand, particularly in remote and sparsely populated regions, necessitates innovative and cost-effective electrical distribution solutions. Traditional Rural Electrification (RE) methods, like Conventional Rural Electrification (CRE), have proven economically unfeasible in such areas due to high infrastructure costs and low electricity demand. Consequently, Unconventional Rural Electrification (URE) technologies, such as Capacitor Coupled Substations (CCS), are gaining attention as viable alternatives. This study presents the design and simulation of an 80 kW CCS system, which taps power directly from a 132 kV transmission line to supply low-voltage consumers. The critical components of the CCS, the capacitors are calculated, then a MATLAB/Simulink model with the attained results is executed. Mathematical representation and state-space representation for maintaining the desired tapped voltage area also developed. The research further explores the feasibility and operational performance of this CCS configuration, aiming to address the challenges of rural electrification by offering a sustainable and scalable solution. The results show that the desired value of the tapped voltage can be achieved at any level of High Voltage (HV) with the selection of capacitors that are correctly rated. With an adequately designed control strategy, the research also shows that tapped voltage can be attained under both steady-state and dynamic loads. By leveraging CCS technology, the study demonstrates the potential for delivering reliable electricity to underserved areas, highlighting the system’s practicality and effectiveness in overcoming the limitations of conventional distribution methods.
文摘新型电力系统和智能电网储能技术是实现“降碳、减排、节能”目标的重要路径,也是发展绿色经济和清洁能源的重要举措.对地铁列车能量调度及其制动能量回收与储存展开研究.首先,分析了超级电容器组和蓄电池组件混合储能技术原理和结构特点.其次,改善列车制动能量回收率,加强荷电状态(State of Charge,SOC)调度过程的可控性和灵活性,为电能协同利用与回收提供安全运行保障和智能检测.实验与仿真结果表明,采用混合储能技术优化后的列车制动能量损失单位里程每小时降低2000 W,牵引网压电量回收率提升了15%,电流传输稳定效率提升8%,列车用电调度效率和SOC估算精准度分别提高了约10%和12%,有效验证该混合储能优化方案的可行性.
文摘带脉冲功率负载的直流供电系统现已广泛应用于电动车、舰船及航空等领域。当脉冲负载发生突变时,整流发电机端电压会随之变化,对整个供电系统的稳定性造成负面影响,此时,滤波电容起到了关键作用。直流供电系统中的滤波电容通常采用电解电容。电解电容存在寄生参数等效串联电阻(equivalent series resistance,ESR),会引起输出电压波形畸变及电压大小的变化。为此,该文提出一种考虑滤波电容寄生参数ESR的双三相整流发电机带脉冲负载的瞬时电压计算方法。首先,建立考虑滤波电容寄生参数ESR的带脉冲功率负载的双三相整流发电机等效瞬态数学模型;其次,通过双三相整流发电机瞬态有限元仿真同负载突变实验进行对比,验证所提出的考虑滤波电容寄生参数ESR的双三相整流发电机等效模型负载突变的瞬时电压计算方法的必要性与可行性;最后,分析滤波电容C及其寄生参数ESR对双三相整流发电机直流侧电压的影响。结果表明,建立的等效模型具有较高的准确性,同时,表明考虑滤波电容寄生参数ESR对整流发电机直流测电压的研究对提高整个直流供电系统电能质量具有重要意义。
文摘为了契合绿色可再生能源发展理念,自供电环境能量收集系统已逐渐成为替代传统电池的高效解决方案,可克服传统电池在重量、尺寸及循环寿命等方面的局限性。针对压电源的时变特性,设计了一种基于其特性的快速最大功率点跟踪(Maximum Power Point Tracking,MPPT)电路架构。对压电源的阻抗特性进行分析,采用了基于快速开关电容采样的开路电压采样MPPT算法,有效实现跟踪精度和动态响应速度的协同优化。最后,基于0.18μm BCD工艺对电路进行设计,仿真结果表明:MPPT的跟踪时间为0.36 ms,最大追踪精度可达99.4%。
