Flexibility in transmission switching for congestion management
In decentralized dispatch philosophy, system operator (SO) only deviate the final schedules in order to maintain network security (i.e. line overloading, outages, voltage and frequency deviations, etc. in real time operation. Before going for the dispatch deviations, SO has the option of changing the network topology (i.e. switching of transmission lines) so as to redistribute the power from anticipated overloaded lines to under utilized lines based on Kirschoff's laws. Presently, this is performed based on SO's experience which may alleviate the overloading, however, this may not be the optimal way. Moreover, change of network topology may initiate steady state angular stability issues in case of any erroneous set of schedules. Therefore, this paper proposes a mixed integer type transmission switching problem (TSP) so as to optimally define the set of lines to be opened in order to alleviate overloading such that the angular stability is maintained. A detailed comparison of the proposed formulation with and without steady state angular stability constraints are presented. It is observed that for the same set of schedules, the number of lines to be opened changes with respect to the steady state angular stability constraints. The proposed formulation is verified on PJM 5 bus and IEEE 118 bus system.
2016 National Power Systems Conference (NPSC)