城市电网在发生N-1故障后,极可能新增运行风险,导致N-1-1时出现大面积停电事故。为管控城市电网N-1后运行风险,该文提出一种改进双智能体竞争双深度Q网络(dueling double deep Q network,D3QN)的城市电网N-1风险管控转供策略。根据风险...城市电网在发生N-1故障后,极可能新增运行风险,导致N-1-1时出现大面积停电事故。为管控城市电网N-1后运行风险,该文提出一种改进双智能体竞争双深度Q网络(dueling double deep Q network,D3QN)的城市电网N-1风险管控转供策略。根据风险管控原则,提出一种无需额外历史数据、考虑备自投装置、单供变电站风险和单供负荷母线风险的N-1场景指标;建立计及动作次序、指标间关系的负荷转供三阶段求解模型。以含预动作-变化探索值选择策略的改进双智能体D3QN方法,将负荷转供分为多个子转供环节学习,使转供思路清晰化,对动作空间进行降维,提高训练寻优效果,得到管控N-1风险的负荷转供策略。通过城市电网多场景算例分析,验证该文模型和方法的有效性。展开更多
The existing liability division methods for harmonic pollution are either inexplicit or incomplete in physical meaning. To compensate these defects, two new methods are proposed based on line-transferred power compone...The existing liability division methods for harmonic pollution are either inexplicit or incomplete in physical meaning. To compensate these defects, two new methods are proposed based on line-transferred power components in this paper. At first, all harmonic sources are represented by ideal equivalent current source, line current components and bus voltage components of a source are determined by stimulation of this source with all other sources disabled. Then, the line-trans- ferred power component owing to a source under all sources action together is determined by the theory of line-transferred power components, and called source’s line-transferred power component. At last, the liability of a source for line-end harmonic pollution is divided by two methods: the ration of the source’s line-transferred active power component to the total line-transferred power, and the ration of projection of the source’s line-transferred complex power component to absolute value of the total line-transferred complex power. These two methods are taken into account not only harmonic voltage but also harmonic current in the liability division. Simulation results show that the proposed liability division method based on active power component is the most effective and ideal one.展开更多
This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated i...This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated in isolated state are identified. Second, different schemes are proposed for generator mode switching from on-grid to off-grid state through comparison and mechanism analysis. Third, the time domain model and frequency domain model of the isolated generator governor are constructed to respectively estimate the primary frequency performance and small signal stability. Parameter sets that satisfy the primary frequency performance and small signal stability are acquired as optimal values of governor control parameters. Finally, the measurement-based parameters of the governor are identified and validated using simulations to demonstrate the feasibility and effectiveness of the method.展开更多
光伏发电系统大量接入电网,会导致电网强度下降,进而限制光伏并网逆变器(grid-connected inverter,GCI)功率输出能力。因此,需要对弱电网下GCI静态功率稳定运行区域与优化控制开展研究。以GCI静态功率稳定运行为目标,以输出电流幅值和...光伏发电系统大量接入电网,会导致电网强度下降,进而限制光伏并网逆变器(grid-connected inverter,GCI)功率输出能力。因此,需要对弱电网下GCI静态功率稳定运行区域与优化控制开展研究。以GCI静态功率稳定运行为目标,以输出电流幅值和公共连接点(point of common coupling,PCC)电压允许范围为约束,确定了GCI在不同短路比(short circuit ratio,SCR)区间内的运行方式,并给出了相应的电流参考值计算方法;为提高GCI在低SCR下运行的稳定性,提出了一种阻抗重塑优化控制方法。该方法在锁相环前级增加了基于准降阶谐振控制器的正负序分离环节,使得系统中频段相位整体较为平稳。同时在电流环引入幅值相位补偿环节,整体增大了系统中频段相位;搭建了仿真模型,在SCR值为1的情况下,所提阻抗重塑优化控制方法仍能保证GCI的稳定性,并基于所提阻抗重塑优化控制方法,验证了GCI静态功率稳定运行区域的正确性。展开更多
文摘城市电网在发生N-1故障后,极可能新增运行风险,导致N-1-1时出现大面积停电事故。为管控城市电网N-1后运行风险,该文提出一种改进双智能体竞争双深度Q网络(dueling double deep Q network,D3QN)的城市电网N-1风险管控转供策略。根据风险管控原则,提出一种无需额外历史数据、考虑备自投装置、单供变电站风险和单供负荷母线风险的N-1场景指标;建立计及动作次序、指标间关系的负荷转供三阶段求解模型。以含预动作-变化探索值选择策略的改进双智能体D3QN方法,将负荷转供分为多个子转供环节学习,使转供思路清晰化,对动作空间进行降维,提高训练寻优效果,得到管控N-1风险的负荷转供策略。通过城市电网多场景算例分析,验证该文模型和方法的有效性。
文摘The existing liability division methods for harmonic pollution are either inexplicit or incomplete in physical meaning. To compensate these defects, two new methods are proposed based on line-transferred power components in this paper. At first, all harmonic sources are represented by ideal equivalent current source, line current components and bus voltage components of a source are determined by stimulation of this source with all other sources disabled. Then, the line-trans- ferred power component owing to a source under all sources action together is determined by the theory of line-transferred power components, and called source’s line-transferred power component. At last, the liability of a source for line-end harmonic pollution is divided by two methods: the ration of the source’s line-transferred active power component to the total line-transferred power, and the ration of projection of the source’s line-transferred complex power component to absolute value of the total line-transferred complex power. These two methods are taken into account not only harmonic voltage but also harmonic current in the liability division. Simulation results show that the proposed liability division method based on active power component is the most effective and ideal one.
基金supported by the Fujian Provincial Government Project (Title: Research on whole process evaluation of dynamic stability and control strategy in condition of grid connection of ultra-high voltage and large scale penetration of nuclear power.No.2015H0023)the State Grid Science & Technology Project (Title: Research on the improvement on stability of primary frequency of generator in account of the tolerance of equipment.No.52130417002P)the Key project of State Grid Fujian Electric Power Company,Ltd (research on key technologies of primary frequency power oscillation mechanism analysis and inhibition measures in large-scale unit in Fujian power grid.No.52130417000J)
文摘This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated in isolated state are identified. Second, different schemes are proposed for generator mode switching from on-grid to off-grid state through comparison and mechanism analysis. Third, the time domain model and frequency domain model of the isolated generator governor are constructed to respectively estimate the primary frequency performance and small signal stability. Parameter sets that satisfy the primary frequency performance and small signal stability are acquired as optimal values of governor control parameters. Finally, the measurement-based parameters of the governor are identified and validated using simulations to demonstrate the feasibility and effectiveness of the method.
文摘光伏发电系统大量接入电网,会导致电网强度下降,进而限制光伏并网逆变器(grid-connected inverter,GCI)功率输出能力。因此,需要对弱电网下GCI静态功率稳定运行区域与优化控制开展研究。以GCI静态功率稳定运行为目标,以输出电流幅值和公共连接点(point of common coupling,PCC)电压允许范围为约束,确定了GCI在不同短路比(short circuit ratio,SCR)区间内的运行方式,并给出了相应的电流参考值计算方法;为提高GCI在低SCR下运行的稳定性,提出了一种阻抗重塑优化控制方法。该方法在锁相环前级增加了基于准降阶谐振控制器的正负序分离环节,使得系统中频段相位整体较为平稳。同时在电流环引入幅值相位补偿环节,整体增大了系统中频段相位;搭建了仿真模型,在SCR值为1的情况下,所提阻抗重塑优化控制方法仍能保证GCI的稳定性,并基于所提阻抗重塑优化控制方法,验证了GCI静态功率稳定运行区域的正确性。
