Controlling reactive power flows in boundary transformers

This paper presents the results of a study of the different alternatives that System Operators use to address the reactive power flow control problem in transmission/subtransmission boundary transformers. The control problem is formulated and solved using a conventional OPF algorithm including additional constraints to keep reactive power flows between imposed limits. The problems arising from the inclusion of these new restrictions, along with the need to distinguish between networks operated by different agents (TSO, DSOs), are presented and discussed.