This paper describes a prototype power delivery system developed for high voltage electronic current transformer （ECT） that uses laser light to transfer power to and communicates with the primary converter. The desi...This paper describes a prototype power delivery system developed for high voltage electronic current transformer （ECT） that uses laser light to transfer power to and communicates with the primary converter. The design is based on optical-to-electrical power converters, solid-state diode lasers and optical fibers. Command signals are transmitted via the same up-fiber used to send power from secondary power supply to primary converter. The upward data transmission is completed during the brief interruption of power delivery without affecting steady power-supply. A simple comparator added to the primary converter can take the command data. Experimental results show that the fibers can provide reliable up-link for data transmission at 200 kb/s from the secondary to the primary converter. Based on the delivery system, the secondary converter can control three auxiliary channels to provide additional information. These monitoring channels are used in a time-multiplexing mode to provide information about the operation temperature, voltage and current at the remote unit for monitoring the ECT. This preventive maintenance or built-in test can increase reliability by giving early warning for necessary maintenance request.展开更多
A high performance current and voltage measurement system has been developed in power system. The system is composed of two parts: one current measurement element and one voltage measurement element. A Rogowski coil ...A high performance current and voltage measurement system has been developed in power system. The system is composed of two parts: one current measurement element and one voltage measurement element. A Rogowski coil and a capacitive voltage divider are used respectively for the line current and voltage measurements. Active electronic components are used to modulate signal, and power supply for these components is drawn from power line via an auxiliary current transformer. Measurement signal is transmitted by optical fibers, which is resistant to electromagnetic induction and noise. With careful design and the use of digital signal processing technology, the whole system can meet 0.5% accuracy for metering and provides large dynamic range coupled with good accuracy for protective relaying use.展开更多
Power electronic zigzag transformer is an attractive solution for the flexible interconnection of smart distribution networks.It is constituted by slow-response and low-precision thyristor converters and fast-response...Power electronic zigzag transformer is an attractive solution for the flexible interconnection of smart distribution networks.It is constituted by slow-response and low-precision thyristor converters and fast-response and high-accuracy voltage source converters.This paper models its primary circuit and addresses its basic operation mechanism.Then a dual-timescale control scheme is investigated to realize the coordinated regulation of both types of converter.A simulation case is established in PSCAD containing interconnected mid-voltage distribution networks.Simulations with poor-and well-matched control timescales are both carried out.And accordingly,the power flow controllability under these conditions is compared.When the shorter control timescale is no more than tenth of the longer one,the power electronic zigzag transformer will operate with satisfying performances.展开更多
为有效降低电容型电子式电压互感器EVT(electronic voltage transformer)的主电容量,以研制的110k V电容型EVT分压器为例,建立了其有限元模型并仿真研究了施加屏蔽对分压器性能的影响,优化结构参数并获得了主电容量的最优值。仿真和计...为有效降低电容型电子式电压互感器EVT(electronic voltage transformer)的主电容量,以研制的110k V电容型EVT分压器为例,建立了其有限元模型并仿真研究了施加屏蔽对分压器性能的影响,优化结构参数并获得了主电容量的最优值。仿真和计算结果表明:施加屏蔽可以有效减小杂散电容对测量准确度的影响;外屏蔽的半径和安装高度是设计时需要考虑的重要参数;通过优化结构参数,可使主电容量为500 p F的EVT分压器的测量准确度小于0.1%。展开更多
双电源输入级联型电力电子变压器(dual power supply cascaded-type power electronic transformer,DPSC-PET)与两路供电电源相连,运行可靠性高、方式灵活,在中低压配电网中应用前景广泛,深入研究其电压暂降耐受能力与调节方法,对于维...双电源输入级联型电力电子变压器(dual power supply cascaded-type power electronic transformer,DPSC-PET)与两路供电电源相连,运行可靠性高、方式灵活,在中低压配电网中应用前景广泛,深入研究其电压暂降耐受能力与调节方法,对于维持暂降期间DPSC-PET的高效能量传输、保证系统优质供电具有重要意义。首先,分析DPSC-PET的拓扑与控制策略;其次,针对引起系统传输功率缺额最严重的三相对称电压暂降,分析DPSC-PET暂降耐受能力限制因素;然后,从功率平衡角度出发,提出一种不同输入侧发生暂降时DPSC-PET耐受能力实时分析与双输入端口功率协同调节方法,以实现暂降下低压直流母线电压恢复,提升DPSC-PET应对暂态扰动的能力;最后,搭建DPSC-PET仿真模型,对不同输入侧发生不同程度的电压暂降场景进行仿真。结果表明,所提调节方法能有效提升DPSC-PET的暂降耐受能力。展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No.50447006）
文摘This paper describes a prototype power delivery system developed for high voltage electronic current transformer （ECT） that uses laser light to transfer power to and communicates with the primary converter. The design is based on optical-to-electrical power converters, solid-state diode lasers and optical fibers. Command signals are transmitted via the same up-fiber used to send power from secondary power supply to primary converter. The upward data transmission is completed during the brief interruption of power delivery without affecting steady power-supply. A simple comparator added to the primary converter can take the command data. Experimental results show that the fibers can provide reliable up-link for data transmission at 200 kb/s from the secondary to the primary converter. Based on the delivery system, the secondary converter can control three auxiliary channels to provide additional information. These monitoring channels are used in a time-multiplexing mode to provide information about the operation temperature, voltage and current at the remote unit for monitoring the ECT. This preventive maintenance or built-in test can increase reliability by giving early warning for necessary maintenance request.
文摘A high performance current and voltage measurement system has been developed in power system. The system is composed of two parts: one current measurement element and one voltage measurement element. A Rogowski coil and a capacitive voltage divider are used respectively for the line current and voltage measurements. Active electronic components are used to modulate signal, and power supply for these components is drawn from power line via an auxiliary current transformer. Measurement signal is transmitted by optical fibers, which is resistant to electromagnetic induction and noise. With careful design and the use of digital signal processing technology, the whole system can meet 0.5% accuracy for metering and provides large dynamic range coupled with good accuracy for protective relaying use.
基金This work was supported by the National Natural Science Foundation of China(51490680,51490683).
文摘Power electronic zigzag transformer is an attractive solution for the flexible interconnection of smart distribution networks.It is constituted by slow-response and low-precision thyristor converters and fast-response and high-accuracy voltage source converters.This paper models its primary circuit and addresses its basic operation mechanism.Then a dual-timescale control scheme is investigated to realize the coordinated regulation of both types of converter.A simulation case is established in PSCAD containing interconnected mid-voltage distribution networks.Simulations with poor-and well-matched control timescales are both carried out.And accordingly,the power flow controllability under these conditions is compared.When the shorter control timescale is no more than tenth of the longer one,the power electronic zigzag transformer will operate with satisfying performances.
文摘为有效降低电容型电子式电压互感器EVT(electronic voltage transformer)的主电容量,以研制的110k V电容型EVT分压器为例,建立了其有限元模型并仿真研究了施加屏蔽对分压器性能的影响,优化结构参数并获得了主电容量的最优值。仿真和计算结果表明:施加屏蔽可以有效减小杂散电容对测量准确度的影响;外屏蔽的半径和安装高度是设计时需要考虑的重要参数;通过优化结构参数,可使主电容量为500 p F的EVT分压器的测量准确度小于0.1%。
文摘双电源输入级联型电力电子变压器(dual power supply cascaded-type power electronic transformer,DPSC-PET)与两路供电电源相连,运行可靠性高、方式灵活,在中低压配电网中应用前景广泛,深入研究其电压暂降耐受能力与调节方法,对于维持暂降期间DPSC-PET的高效能量传输、保证系统优质供电具有重要意义。首先,分析DPSC-PET的拓扑与控制策略;其次,针对引起系统传输功率缺额最严重的三相对称电压暂降,分析DPSC-PET暂降耐受能力限制因素;然后,从功率平衡角度出发,提出一种不同输入侧发生暂降时DPSC-PET耐受能力实时分析与双输入端口功率协同调节方法,以实现暂降下低压直流母线电压恢复,提升DPSC-PET应对暂态扰动的能力;最后,搭建DPSC-PET仿真模型,对不同输入侧发生不同程度的电压暂降场景进行仿真。结果表明,所提调节方法能有效提升DPSC-PET的暂降耐受能力。
