Frequency deviation can be used as an indicator of imbalance between supply and demand. When generation is insufficient, it can cause frequency decline in a power system operation. Implementing under frequency load sh...Frequency deviation can be used as an indicator of imbalance between supply and demand. When generation is insufficient, it can cause frequency decline in a power system operation. Implementing under frequency load shedding (UFLS) is one of the common methods to overcome this problem. This paper proposes a novel approach for adaptive load shedding. The concept is an extension of shared and targeted load shedding using reserve margin. The optimal system configuration is then selected from those candidates to fulfill operational objectives. Operational constraints related to system parameters, threshold frequency, total of load shed and control area including line capacity are considered. An example using four sub-areas connected to an external system shows that the proposed regional coordination as an adaptive UFLS is feasible.展开更多
To restore the distribution systems in emergency states with the minimum load shedding, a novel Tabu search approach is put forward. The set of tripped switches is used as candidate solution. Some virtual tripped node...To restore the distribution systems in emergency states with the minimum load shedding, a novel Tabu search approach is put forward. The set of tripped switches is used as candidate solution. Some virtual tripped nodes are defined at the ends of the terminal nodes and by the source nodes. The neighborhood searching is committed by moving a tripped switch to the adjacent node of its upper stream and down stream, respectively. A Tabu list is formed for the tripped switches. The index is to energize as much as possible loads with as less as possible operated times. The electrical limitations and the voltage criterions are used as constrictions. The global aspiration criterion is adopted. An example is given, which shows that the proposed approach is feasible and can deal with complicated indexes.展开更多
为研究铁塔对重冰区高压双回输电线路脱冰跳跃的影响,以重冰区220 k V双回输电线路为对象,分别建立导线-绝缘子模型及考虑铁塔影响的塔线体系模型,并对比分析两种模型的计算结果。通过对比发现,无论是否有风,导线-绝缘子模型脱冰档导线...为研究铁塔对重冰区高压双回输电线路脱冰跳跃的影响,以重冰区220 k V双回输电线路为对象,分别建立导线-绝缘子模型及考虑铁塔影响的塔线体系模型,并对比分析两种模型的计算结果。通过对比发现,无论是否有风,导线-绝缘子模型脱冰档导线的跳跃高度较塔线体系模型大,而未脱冰档导线的跳跃高度却小于塔线模型,并且差值均随着脱冰率的增大而减小。除此之外,改变铁塔的刚度,发现其跳跃高度变化很小。这说明铁塔的刚度对于塔线体系模型的计算结果影响很小,进一步说明造成两种模型差异的主要原因是塔线耦合效应。展开更多
文摘Frequency deviation can be used as an indicator of imbalance between supply and demand. When generation is insufficient, it can cause frequency decline in a power system operation. Implementing under frequency load shedding (UFLS) is one of the common methods to overcome this problem. This paper proposes a novel approach for adaptive load shedding. The concept is an extension of shared and targeted load shedding using reserve margin. The optimal system configuration is then selected from those candidates to fulfill operational objectives. Operational constraints related to system parameters, threshold frequency, total of load shed and control area including line capacity are considered. An example using four sub-areas connected to an external system shows that the proposed regional coordination as an adaptive UFLS is feasible.
文摘To restore the distribution systems in emergency states with the minimum load shedding, a novel Tabu search approach is put forward. The set of tripped switches is used as candidate solution. Some virtual tripped nodes are defined at the ends of the terminal nodes and by the source nodes. The neighborhood searching is committed by moving a tripped switch to the adjacent node of its upper stream and down stream, respectively. A Tabu list is formed for the tripped switches. The index is to energize as much as possible loads with as less as possible operated times. The electrical limitations and the voltage criterions are used as constrictions. The global aspiration criterion is adopted. An example is given, which shows that the proposed approach is feasible and can deal with complicated indexes.
文摘为研究铁塔对重冰区高压双回输电线路脱冰跳跃的影响,以重冰区220 k V双回输电线路为对象,分别建立导线-绝缘子模型及考虑铁塔影响的塔线体系模型,并对比分析两种模型的计算结果。通过对比发现,无论是否有风,导线-绝缘子模型脱冰档导线的跳跃高度较塔线体系模型大,而未脱冰档导线的跳跃高度却小于塔线模型,并且差值均随着脱冰率的增大而减小。除此之外,改变铁塔的刚度,发现其跳跃高度变化很小。这说明铁塔的刚度对于塔线体系模型的计算结果影响很小,进一步说明造成两种模型差异的主要原因是塔线耦合效应。
