Research On Multi-level Coordinated Real-time Scheduling Method Under Large-scale Power Loss

The transmission capacity of ultra high voltage DC(UHVDC)is very large,and DC blocking will cause a large-scale power loss in the receiving power grid.At present,scheduling plan of the state,regional and provincial grid is independent,which is not conducive to the multi-level integrated adjustment and active power rebalance of the power system.At the same time,in a provincial power grid,there are units that are managed by different dispatching agencies at the same time.The conventional real-time dispatching method cannot achieve the coordinated scheduling of units that managed by different dispatch agencies.Aiming at the above issues,multi-level coordinated real-time scheduling strategy dealing with large-scale power loss was studied in this paper.Firstly,calculation method for the safe callable reserve of units and provincial grids were studied.Based on available transfer capability(ATC),a calculation model of maximum callable capacity for regional power grid after large-scale power loss was constructed.According to the maximum callable capacity of power grid and amount of power loss,the hierarchical division method of power loss and the principle of integrated adjustment of multi-level planning at different levels were proposed.For different scheduling plan startup levels,a multi-level real-time scheduling plan coordination process was designed based on the existing real-time planning of the state,regional and provincial grid.Then,in view of problems that both provincial dispatching units and regional dispatching units existed in a provincial grid,and conventional real-time scheduling methods could not be applied under large-scale power loss cases,a model for the allocation of active power adjustment and output tracking between provincial dispatching units and regional dispatching units was constructed.For the cases that the provincial dispatching units or regional dispatching units might not be able to track the allocated active adjustment,a coordination strategy for provincial dispatching units and regional dispatching units was proposed,followed by an output correction model.Together,a set of real-time scheduling method coordinated provincial and regional dispatching units that were suitable for provincial power grids under large power loss was formed.Finally,on the basis of considering the transmission capacity of the tie line and the regional active power balance constraints,a cross-regional tie line plan adjustment model was constructed based on the principle of minimum adjustment.Taking into account the constraint conditions such as provincial reserve,tie line transmission capacity,and regional active power balance,the optimization model of the regional tie line plan was constructed with the target of minimizing the total power generation cost and tie line plan adjustment cost.Research results show that callable capacity calculation of the regional grid based on ATC and power loss hierarchy was reasonable.Coordinated output adjustment of provincial dispatching units and regional dispatching units is conducive to the rebalance of provincial grid.The tie-line planning adjustment model could achieve the optimal allocation of large-scale power loss among the provincial power grids,with all the tie line power under safety limits.