Coordinated Economic Dispatch of Coupled Transmission and Distribution Systems Using Heterogeneous Decomposition

Because distributed generations are extensively integrated into active distribution grids (ADGs), the transmission and distribution coordinated economic dispatch (TDCED) should be investigated to optimally dispatch the generation resources and evaluate the locational marginal prices (LMPs) of the entire system. In this paper, the TDCED problem is formulated, and a new heterogeneous decomposition (HGD) algorithm is proposed. In the HGD algorithm, the transmission LMP at the boundary bus and ADGs' power are exchanged among transmission and ADGs. The optimality and convergency of HGD are proven and numerically verified. In addition, several related issues are further discussed: a) methods to improve the convergency of HGD, b) considerations regarding security issues and voltage constraints in TDCED and corresponding modified HGD algorithms, and c) the practicality of HGD in either separate or transparent interaction modes of transmission and distribution in future grids. Numerical simulations indicate that the generation resources are optimally utilized and that LMPs are reasonably evaluated in TDCED. Congestion in the traditional isolated dispatch mode can also be prevented. Moreover, simulations on several systems from T6D2 to T300D60 verify that the HGD algorithm is an efficient and robust algorithm with limited communication burdens to solve TDCED.