Research On The Effect Of Thermal Units' Start-up Time On Power System Restoration

The network reconfiguration is an important stage in the process of the power system black start, attracted by many uncertain factors because of its system structure changes constantly,control operation frequently. In power systems mainly consisting of thermal units, the time for unit's start-up and restoration determines the duration of network reconfiguration following large-area blackout. In this paper, centralized-operation simulator of power plant is first employed to investigate the starting process of thermal units thereby establishing the relation between start-up time and the cumulative downtime corresponding to typical unit types. On this basis, a parallel recovery strategy is proposed for network reconfiguration. According to this strategy, the unit nodes are viewed as the load nodes with the highest priority and dealt with the other load nodes together. After available crank power in each stage is used as constraints, parallel restoration paths are optimized with Prim algorithm. The application to IEEE 30-bus system and IEEE 57-bus system verify that reconfiguration scheme achieved can make full use of the crank power thereby restoring multi units and paths simultaneously so that the duration is reduced effectively, which is significant for organizing restoration scenarios rapidly and orderly following a large-scale blackout. Also it receives the unit recovery time which provides the time information of important guiding significance for network reconfiguration after blackout. This paper also considered the grid units start reconstruction after the failed recovery, and the establishment of the related index on the transfer path of uncertainty assessment, identification of unit start failure subsequent recovery of the system. Finally, to verify the relevant examples, the results show that the recovery strategy is effective and practical, has a more realistic operational guidance for dispatchers.