Targeted conversion of AC lines to DC lines for improved power system dispatch

Abstract

In this paper the concept of targeted conversion of AC lines to DC lines is proposed for improved securityconstrained economic dispatch by incorporating the converted line into the formulation to improve flow pattern control and relieve flow constraints on both the converted line and the remaining AC system. The proposed model treats the flow on the converted line as an independent control variable for the operator to utilize. It is shown that the introduction of this additional control variable significantly decreases the dispatch cost through congestion relief. Wind curtailment due to transmission congestion, is also shown to be significantly relieved. The technical feasibility of the implementation, combined with the economic benefits, suggests that targeted conversion of AC lines to DC lines a promising approach to best utilizing transmission grid for maximized social welfare. Illustrative examples on a 24-bus system demonstrate the technical feasibility and economic benefits for renewable energy resources by use of the proposed conversion.

A Hybrid Transmission Grid Architecture Enabling Efficient Optimal Power Flow

“…To this end, the conversion of AC lines to high-voltage direct current (HVDC) lines is a possible option [5]- [8]. HVDC lines feature a controllable power flow and provide dynamic voltage support at the terminals [9], which can further enhance the capacity of the connected AC grid [9], [10] and renders it particularly appealing from a technological point of view.…”

Upgrading the Power Capacity of a Three-Conductor MVAC Line by Converting to DC

“…Hence, the IEEE forecast for 2050 [4] assumes that power systems of the future will combine the advantages of variable frequency AC and DC. Several works have shown that a combination of AC and DC in power systems may bring significant benefits at both transmission and distribution levels [8][9][10][11][12][13]. The advantages of hybrid AC/DC grids include better power flow and nodes voltage control as well as reduced power and voltage losses.…”