An active / reactive power market dispatch model including soft constraints

Abstract

This paper describes an active / reactive dispatch model based on bids transmitted by market agents to the Market Operator. The Market Operator economic schedule is then conveyed to the System Operator in order to evaluate its technical feasibility. If it is unfeasible, the System Operator runs a secondary market based on adjustment bids aiming at regaining feasibility while changing as little as possible the initial economic schedule. This secondary market is modeled as a non-linear optimization problem including the AC power flow equations, branch flow and nodal voltage limits as well as constraints related with the capability curve of synchronous generators. This problem is converted into a Symmetric Fuzzy Decision formulation admitting that branch flow and nodal voltage limit constraints have a soft nature. The resulting problem is solved using a Sequential Linear Programming, SLP, approach. The paper includes a case study based on the 24 bus IEEE Test System to illustrate its application and interest of this approach to restructured power systems.