HVDC Link Benefits for the AC Transmission System Operation. Technical and Economic Aspects.

Abstract

This work explores the benefits that can be obtained in a conventional alternating current electrical power system (HVAC) by means of proper operation of a direct current transmission link (HVDC). The technical and economic advantages of HVDC systems compared to HVAC are well known mainly for their convenience for long distances and large power transmissions; however, a study dedicated to the operation criteria of HVDC links may maximize its benefits. Some examples include power loss minimization for the entire interconnection system, reduction in the number of operations of compensation equipment (shunt reactors and capacitors, series capacitors bypass, tap changer movement) and extension of its life cycle, reducing maintenance costs, and better performance of existing control and automatic schemes through joint coordinated operation of the HVDC link in disturbances events scenarios, minimizing the impact on the system. The increase and demographic characteristics of the electrical load in the Argentinian Interconnection System (SADI), along with the fact that the primary resources of energy are far away of the principal consumption centers. As part of those studies, the new HVDC link operation (in a bipolar configuration with optional earth return) was modeled for different load scenarios and seasonality up to 2026-year horizon. The obtained results showed a clear economic advantage due to the operation of the system in an optimum point, minimizing the total system losses and a reduction in the number of maneuvers in the reactive compensation equipment of more than 60%. On the other hand, it was possible to show that there was a more effective utilization of a new network security automation based on an Automatic Generation Disconnection (AGD) scheme designed by contingency events in the SADI, working together with the HVDC link power setpoints, achieving an effectiveness of 100%.