  With the deregulation of power industry, large power users can buy
electricity directly from power producers. For trades between different
regional markets, it is necessary to research on the method to find the
cheapest route for power exchanging. Moreover, as there exists no coordinator
above regional markets, the power routing problem must be solved in a
distributed way. Most previous research are based on power electronic
transformers. Some research proposed EMS of sub-networks as energy routers, but
failed to consider the power flow constraints or did not converge in some
specific cases. Our method is based on the EMS of multiple markets, which saves
cost by eliminating expensive electronic transformers and has high efficiency
in systems with numerous nodes by considering the regional markets as
generalized nodes. We take transmission costs and congestion costs into
consideration, and uses Bellman-Ford algorithm to determine the cheapest route
for power transmission between different regional markets and make convergence
analysis about our algorithm. This method proves effective and convergent when
there is no loop among the markets. A four-market loop-free case was used to
illustrate the efficiency of the method.
