Voltage source converter(VSC) based high voltage direct current(HVDC) transmission is most suited for the wind farm as it allows flexibility for reactive power control in multi-terminal transmission lines and transmit...Voltage source converter(VSC) based high voltage direct current(HVDC) transmission is most suited for the wind farm as it allows flexibility for reactive power control in multi-terminal transmission lines and transmits low power over smaller distance. In this work, a new method has been proposed to detect the fault, identify the section of faults and classify the pole of the fault in DC transmission lines fed from onshore wind farm. In the proposed scheme, voltage signal from rectifier end terminal is extracted with sampling frequency of 1 k Hz given as the input to the detection, classification and section discrimi-nation module. In this work, severe AC faults are also considered for section discrimination. Proposed method uses fuzzy inference system(FIS) to carry out all relaying task. The reach setting of the relay is 99.9% of the transmission line. Besides, the protection covers and discriminates the grounding fault with fault resistance up to 300 Ω.Considering the results of the proposed method, it can beused effectively in real power network.展开更多
基于电压源换流器高压直流输电(voltage source converter based HVDC,VSC-HVDC)的直流系统存在与交流线路并联运行的情况。交直流系统之间相互切换的运行工况复杂,且切换过程存在切换依据难以确定、切换冲击大以及通信延时等问题。为...基于电压源换流器高压直流输电(voltage source converter based HVDC,VSC-HVDC)的直流系统存在与交流线路并联运行的情况。交直流系统之间相互切换的运行工况复杂,且切换过程存在切换依据难以确定、切换冲击大以及通信延时等问题。为解决该问题,在分析VSC-HVDC工作原理、数学模型及其控制策略的基础上,提出了一种大型风电场经VSC-HVDC交直流并联系统并网的运行控制策略,该策略在不改变换流站控制方式的情况下,可实现交直流并联系统运行方式的无缝切换。基于MATLAB/Simulink仿真软件,建立了系统仿真模型,对交直流并联系统稳态运行及动态切换过程进行了仿真分析。仿真结果表明,所提出的控制策略能够较好地实现交直流并联系统有功功率的精确分配和运行方式的无缝切换,算法简单,可靠性高。展开更多
过电流关断试验是柔性直流输电(voltage sourced converter based high voltage direct current transmission,VSC-HVDC)换流阀暂态试验之一,是为了检验换流阀设计的正确性及对桥臂直通工况应力耐受性进行的试验。研究阀过电流关断试验...过电流关断试验是柔性直流输电(voltage sourced converter based high voltage direct current transmission,VSC-HVDC)换流阀暂态试验之一,是为了检验换流阀设计的正确性及对桥臂直通工况应力耐受性进行的试验。研究阀过电流关断试验的试验方法,分析桥臂直通工况下的应力,提出等效试验方法并设计试验电路,最后给出试验电路中阀的应力波形与实际工况下应力波形的对比,结合关键应力等效性分析,验证试验方法和试验电路的等效性。展开更多
针对柔性直流输电(high voltage direct current transmission based on voltage source converter,VSC-HVDC)系统多变量、非线性强的特点,以及传统双闭环比例–积分(proportion integration,PI)控制策略参数整定困难的缺点,对VSC-HVDC...针对柔性直流输电(high voltage direct current transmission based on voltage source converter,VSC-HVDC)系统多变量、非线性强的特点,以及传统双闭环比例–积分(proportion integration,PI)控制策略参数整定困难的缺点,对VSC-HVDC系统换流站级的控制策略进行了讨论。首先对VSC-HVDC的双闭环矢量控制作了介绍,并基于模糊免疫反馈的思想,设计了内环电流控制器;再在MATLAB/Simulink平台中对整流侧有功功率提升和有功功率跌落情况进行了仿真。仿真结果表明:相对于传统的PI控制器,在功率跟踪的综合性能指标以及直流侧电压抗干扰的动态性能上都有较好的表现。展开更多
文摘Voltage source converter(VSC) based high voltage direct current(HVDC) transmission is most suited for the wind farm as it allows flexibility for reactive power control in multi-terminal transmission lines and transmits low power over smaller distance. In this work, a new method has been proposed to detect the fault, identify the section of faults and classify the pole of the fault in DC transmission lines fed from onshore wind farm. In the proposed scheme, voltage signal from rectifier end terminal is extracted with sampling frequency of 1 k Hz given as the input to the detection, classification and section discrimi-nation module. In this work, severe AC faults are also considered for section discrimination. Proposed method uses fuzzy inference system(FIS) to carry out all relaying task. The reach setting of the relay is 99.9% of the transmission line. Besides, the protection covers and discriminates the grounding fault with fault resistance up to 300 Ω.Considering the results of the proposed method, it can beused effectively in real power network.
文摘基于电压源换流器高压直流输电(voltage source converter based HVDC,VSC-HVDC)的直流系统存在与交流线路并联运行的情况。交直流系统之间相互切换的运行工况复杂,且切换过程存在切换依据难以确定、切换冲击大以及通信延时等问题。为解决该问题,在分析VSC-HVDC工作原理、数学模型及其控制策略的基础上,提出了一种大型风电场经VSC-HVDC交直流并联系统并网的运行控制策略,该策略在不改变换流站控制方式的情况下,可实现交直流并联系统运行方式的无缝切换。基于MATLAB/Simulink仿真软件,建立了系统仿真模型,对交直流并联系统稳态运行及动态切换过程进行了仿真分析。仿真结果表明,所提出的控制策略能够较好地实现交直流并联系统有功功率的精确分配和运行方式的无缝切换,算法简单,可靠性高。
文摘过电流关断试验是柔性直流输电(voltage sourced converter based high voltage direct current transmission,VSC-HVDC)换流阀暂态试验之一,是为了检验换流阀设计的正确性及对桥臂直通工况应力耐受性进行的试验。研究阀过电流关断试验的试验方法,分析桥臂直通工况下的应力,提出等效试验方法并设计试验电路,最后给出试验电路中阀的应力波形与实际工况下应力波形的对比,结合关键应力等效性分析,验证试验方法和试验电路的等效性。
文摘针对柔性直流输电(high voltage direct current transmission based on voltage source converter,VSC-HVDC)系统多变量、非线性强的特点,以及传统双闭环比例–积分(proportion integration,PI)控制策略参数整定困难的缺点,对VSC-HVDC系统换流站级的控制策略进行了讨论。首先对VSC-HVDC的双闭环矢量控制作了介绍,并基于模糊免疫反馈的思想,设计了内环电流控制器;再在MATLAB/Simulink平台中对整流侧有功功率提升和有功功率跌落情况进行了仿真。仿真结果表明:相对于传统的PI控制器,在功率跟踪的综合性能指标以及直流侧电压抗干扰的动态性能上都有较好的表现。
