I. Introduction
Market flow is widely used by ISOs/RTOs in the congestion management process. Market flow means the amount of energy flows (or parallel flows) on a specified flowgate or facility as a result of dispatch of generating resources serving market load within a market-based operating entity's market (excluding tagged transactions) [1], [2]. A flowgate is a proxy for transmission limitation and transmission service usage on the interconnected electric power network to maintain stability, keep voltages within appropriate limits, or keep loading within appropriate rating for both normal and contingency conditions. Flowgates are facilities or group of facilities that may act as significant constraint points on the system [1]. A transaction means the transporting of scheduled power from a seller to a buyer along a prescribed contract path. Since all of the bilateral transactions between different balancing authorities (BAs) are tagged in the North American Electric Reliability Corporation (NERC) congestion management process, they are called tagged transactions, and their parallel flow impacts on constraint are defined as tag impacts. In the RTO real-time market operations, the UDS dispatches generation resources and manages constraints or flowgates to meet load economically and reliably. The UDS calculates the UDS flow on a flowgate in a different manner than the market flow calculation. The identification of the relationship between the market flow and the UDS flow is critical to ensure the most cost-effective congestion management for market-operating entities. This paper will attempt to address the connection between them.