| Generally transmission section means a group of transmission lines which haveclosely connection with each other and have the same power flow direction betweenregional power grids. It’s very important in power system safety and stability analysis. Ithas different definition from different points of view. From the perspective of power gridmanagement, it means the tie lines that connect individual power grids. From theperspective of safety and stability of power system, it means the tie lines which should bemonitored and controlled importantly under the constraints of power system static securityand dynamic security.Occurrences of line outages in power systems, in most cases, render the load flowtransferred from the faulted line to the parallel transmission section, which have the samegeneration sources or/and load areas as the outage lines. Analysis of several well-knowblackouts also reveals this characteristic of flow transferring, leading to a conclusion thatpeak vulnerability resides in the parallel transmission section, where power flow increasesmost intensively and cascading trips are most likely to occur. Accordingly, it is necessaryand also of great importance for the security and reliability of the whole network to deploya security protection scheme to this key transmission section.To solve these questions, this paper proposed a new transmission section partition andsearch method which based on the electrical partitioning. According to this method,transmission sections are divided into three kinds, which are initial section (IS), ordinarysection (OS) and key section (KS). They are found out step by step based on differentconstraints. And then, practical and linearizing mathematical models are establishedrespectively for calculating the transfer capability of transmission section restricted byN1security principle. The essential of transmission section power limit is analyzedaccording to the DC power flow. Finally, the validity and availability of proposed methodis verified by the calculation result of CEPRI-36bus system and Hunan power grid. |
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