Feasibility assessment of simultaneous bilateral transactions in a competitive energy market

A large number of transmission transactions is expected to take place with the introduction of competition into the electricity industry. These transactions need to be evaluated ahead of their scheduling time to check their feasibility with regard to the system conditions at the time of scheduling. Transmission system operators would have to honor and execute only transactions as far as the system design and system operating conditions permit. This paper describes a method for determining the available transfer capability (ATC) between any two locations in transmission system (single-area or multi-area) under a given set of system operating conditions. The method is then used to assess the feasibility of simultaneous bilateral transactions with regard to the system economic dispatch and transmission system constraints. Transactions will be classified into feasible and infeasible. Feasible transactions can be accommodated without violating the system economic dispatch and transmission network constraints. Infeasible transactions violate transmission network constraints and cannot be accommodated fully without altering the system economic dispatch. The assessment method provides information on where and how much generation is to be rescheduled in order to accommodate an infeasible transaction. Such information will be useful in deciding whether a particular infeasible transaction is worth serving or not. The IEEE Reliability Test System is used to illustrate the assessment method.