Assessment of Market Flows for Interregional Congestion Management in Electricity Markets

This paper gives the background and role of the market flow in the interregional congestion management process for market-based operating entity and describes the market flow methodology. It proposes that the market flow method calculates the same impact result on a flowgate as the unit dispatch system (UDS) flow does and proves it mathematically. The equivalence of market flow and UDS flow shows that the UDS flow change on a constraint due to the UDS binding will have the same effect on the change in the market flow under the electricity market operations. In addition, it proves that, in an interconnected system, the sum of the market flows of all of the market entities, the generation-to-load impacts of nonmarket entities, and the total tagged transaction impact among the entities is equal to the dc flow for any constraint. The assessment of market flow methodology demonstrates the effectiveness of using the market flow in the congestion management process and coordinated management of transmission constraints. The proposed methodology can help identify the cause of loop flow problem in power systems. The numerical results on a 23-bus test system and a 7917-bus system are also illustrated.