Optimal power flow in VSC-HVDC networks for DC-ISO: Constant current operation

DC Independent System Operator (DC-ISO) is a revolutionary concept; a single entity designed to coordinate, to control and monitor the operation of the DC transmission system. It will be responsible for ensuring the reliability and security of the VSC-HVDC meshed networks in real-time and co-ordinate the supply of and demand for electricity, in a manner that avoids violations of technical and economic standards. This paper proposes a simple methodology for optimal power flow (OPF) allowing constant current operation in a series branch of the VSC-HVDC network in order to cope with one the possible DC-ISO objectives. One of the contribution of this paper is a methodology that allows including new operator objectives as in the OPF problem as a type linear equality constraints, it is based on nodal analysis. Proposed methodology has been thoroughly illustrated and tested with a simple 3-node MVSCDC system, and results show the validity of the proposed approach.