A New Economic Dispatch for Coupled Transmission and Active Distribution Networks via Hierarchical Communication Structure

Traditionally, the economic dispatch problem (EDP) of the bulk generators connected to transmission networks (TNs) is solved in a centralized dispatching center (CDC) while modeling distribution networks as passive loads. With the increasing penetration levels of distributed generation, coordinating the economic dispatch between TNs and active distribution networks (ADNs) became vital to maximizing system efficiency. This article proposes a hierarchical communication structure, which requires minimal upgrades to the CDC, for solving the EDP of coupled TNs and ADNs. Based on the minimal data transfer between the CDC and distribution network operators, the problem is formulated and solved while considering the network losses in both TNs and ADNs. Furthermore, a sensitivity analysis is conducted to assess the effect of the R/X ratio of the distribution lines on the economic dispatch solution and the operational cost of the system. The numerical results demonstrate the effectiveness of the proposed centralized scheme and highlight the significance of considering the network losses of both TNs and ADNs when solving the EDP. The results show that the proposed framework can achieve savings of up to 17.98% by taking into account the network losses of TNs and ADNs.