Research And Applications Of Power System Zone Partitioning Strategy Considering Transmission Congestion

With the continuous development of China's power system,the regional power grid gradually forms an interconnection pattern.Partition management is an important method for the operation and management of modern interconnected power system.Due to the limitation of network transmission capacity,transmission congestion may occur.Transmission congestion has regional influence on power system.Considering transmission congestion to decompose the system into several regions is beneficial to clearly characterize regional power pricing information,optimize regional power consumption structure and assist power grid planning.It also helps to allocate reserve resources reasonably and avoid reserve resource transmission problem caused by network restrictions.We consider the zonal influence of transmission congestion on power grid and research on power grid zone partitioning strategy and its applications.The main research is as follows:Firstly,a power system partition method based on improved spectral clustering algorithm is proposed.Based on the active set theory a potential congested transmission identification strategy is proposed.The power transfer distribution factor corresponding to the potential congested transmission is chosen as the measure of the similarity between nodes,then an undirected weighted graph model is established and the power system is partitioned based on improved spectral clustering algorithm.The marginal price of the nodes belonging to the same area after the partition is similar,which can represent the regional price signal and assist regional decision making.Secondly,to solve the problem of effective reserve resources supply and transmission due to transmission congestion,a dynamic reserve zone partitioning method based on the semi-supervised spectral clustering is proposed.Based on the results of energy-reserve joint optimization model,the risk of the transmission congestion is evaluated with the consideration of wind power uncertainty.The semi-supervision information of the unit group helps to guide the clustering process and divide the system into zones based on spectral clustering method through iteration.The proposed dynamic reserve partition algorithm can automatically determine the number of partitions and effectively solve the problem of reserve resource transmission.Finally,in order to reduce the complexity of power grid and simplify the calculation of power system,a static equivalent method based on zonal aggregation is proposed.Based on the spectral clustering algorithm,the system region is divided according to the potential congested transmission and main flow gate.According to the zone partitioning results,the node polymerization is carried out and the network structure of equivalent model is determined.The parameters of equivalent model are solved by the equivalence of inter-zonal power flow before and after equivalence.The equivalent model has similar structure compared to the complete power system with a low network complexity and high accuracy.It can provide quick and convenient analysis tools for the operation of power system,so that operators can quickly grasp the operation rules of the system and make reasonable scheduling and planning decisions.