快速检测故障并准确实现故障隔离是柔性直流电网的基本运行要求。为提高直流电网运行的可靠性,以典型的4端口柔性直流输电工程为研究对象,针对工程中应用的高压直流断路器提出了一种就近检测电压变化率(rateofchange of voltage,ROCOV)...快速检测故障并准确实现故障隔离是柔性直流电网的基本运行要求。为提高直流电网运行的可靠性,以典型的4端口柔性直流输电工程为研究对象,针对工程中应用的高压直流断路器提出了一种就近检测电压变化率(rateofchange of voltage,ROCOV)的高压直流电网保护控制策略,通过对保护原理的分析提出了保护所需要的故障判据,并给出了动作阈值的整定方法。此外在目前的直流电网保护策略基础上进行了改进,针对易发生保护误动的情况具体地提出了抗扰动的方法和区分区内区外故障的控制策略,最后在PSCAD/EMTDC中搭建了4端口柔性直流输电模型,对不同的工况和故障进行仿真,验证了方法的准确性以及保护动作的选择性、可靠性和速动性,并证明了该方法具有一定的抗干扰性和抗过渡电阻的能力。展开更多
高压直流断路器是多端柔性直流输电工程换流站内重要的电气设备,直接关系到柔直系统运行的可靠性。根据±200 k V高压直流断路器在系统操作合闸过程中,出现的位置信号未及时返回控制系统,断路器后序无法进行分闸操作的故障现象,经...高压直流断路器是多端柔性直流输电工程换流站内重要的电气设备,直接关系到柔直系统运行的可靠性。根据±200 k V高压直流断路器在系统操作合闸过程中,出现的位置信号未及时返回控制系统,断路器后序无法进行分闸操作的故障现象,经报文分析判断和现场故障检测,得出故障原因是断路器开关内极柱分位传感器位置偏移,造成分位信号响应延迟、断路器拒动。最后通过将分位传感器调整至正常工作位置的方法解决了该问题,并提出了需要制定高压直流断路器检修规程及监控后台增加断路器操作次数统计功能的建议。展开更多
The use of overhead lines for power transmission in the future high-voltage and large-capacity voltagesource converter(VSC)-based direct current(DC) grid will significantly increase the probability of temporary faults...The use of overhead lines for power transmission in the future high-voltage and large-capacity voltagesource converter(VSC)-based direct current(DC) grid will significantly increase the probability of temporary faults.To eliminate potential adverse impacts such as erroneous protection, line-insulation failure, and even damage to power electronic devices resulting from a DC breaker reclosing operation with the traditional sequential autoreclosing strategy, a new sequential auto-reclosing strat-egy for hybrid HVDC breakers(HHBs) in VSC-based DC grids is proposed. This strategy is based on the step-by-step operation of the transfer branch in the HHB. As a result,du/dt resulting from the HHB reclosing operation is greatly reduced, and therefore those potential negative impacts can be eliminated. Several other advantages are also presented.The feasibility and validity of the proposed strategy are verified in a four-terminal annular VSC-based DC grid electromagnetic transient model.展开更多
文摘快速检测故障并准确实现故障隔离是柔性直流电网的基本运行要求。为提高直流电网运行的可靠性,以典型的4端口柔性直流输电工程为研究对象,针对工程中应用的高压直流断路器提出了一种就近检测电压变化率(rateofchange of voltage,ROCOV)的高压直流电网保护控制策略,通过对保护原理的分析提出了保护所需要的故障判据,并给出了动作阈值的整定方法。此外在目前的直流电网保护策略基础上进行了改进,针对易发生保护误动的情况具体地提出了抗扰动的方法和区分区内区外故障的控制策略,最后在PSCAD/EMTDC中搭建了4端口柔性直流输电模型,对不同的工况和故障进行仿真,验证了方法的准确性以及保护动作的选择性、可靠性和速动性,并证明了该方法具有一定的抗干扰性和抗过渡电阻的能力。
文摘高压直流断路器是多端柔性直流输电工程换流站内重要的电气设备,直接关系到柔直系统运行的可靠性。根据±200 k V高压直流断路器在系统操作合闸过程中,出现的位置信号未及时返回控制系统,断路器后序无法进行分闸操作的故障现象,经报文分析判断和现场故障检测,得出故障原因是断路器开关内极柱分位传感器位置偏移,造成分位信号响应延迟、断路器拒动。最后通过将分位传感器调整至正常工作位置的方法解决了该问题,并提出了需要制定高压直流断路器检修规程及监控后台增加断路器操作次数统计功能的建议。
基金supported by National Key R&D Program of China (No. 2017YFB0902400)
文摘The use of overhead lines for power transmission in the future high-voltage and large-capacity voltagesource converter(VSC)-based direct current(DC) grid will significantly increase the probability of temporary faults.To eliminate potential adverse impacts such as erroneous protection, line-insulation failure, and even damage to power electronic devices resulting from a DC breaker reclosing operation with the traditional sequential autoreclosing strategy, a new sequential auto-reclosing strat-egy for hybrid HVDC breakers(HHBs) in VSC-based DC grids is proposed. This strategy is based on the step-by-step operation of the transfer branch in the HHB. As a result,du/dt resulting from the HHB reclosing operation is greatly reduced, and therefore those potential negative impacts can be eliminated. Several other advantages are also presented.The feasibility and validity of the proposed strategy are verified in a four-terminal annular VSC-based DC grid electromagnetic transient model.
