Poorly damped electromechanical oscillation in the 345 kV interconnection between Argentina and Chile

Abstract

Small signal stability problems are one of the major threats to grid stability and reliability. An unstable oscillatory mode can cause large-amplitude oscillations and may result in system breakup and large scale blackouts. There is an existent and non-operating, 345 kV transmission line between Argentinean Interconnected System (SADI) and the Northern Interconnected System (SING), which is one of the two major electrical isolated power systems in Chile with current surplus capacity and ongoing renewable energy developments. In the past, this line was only dedicated to transmit power to Chile from a power plant located in Argentina but isolated from its power system. Recently, there has been an increasing interest in restarting the operation of the 345 kV transmission line to allow the interconnected operation of both systems, SADI and SING, with growing power flows in both directions. Last year, the Company AES GENER (owner of the 345 kV transmission line and some generation plants in Argentina and Chile) received the authorization from both governments to start interconnection feasibility studies [5], to make interconnection tests and to develop operational procedures. Starting up the operation of the transmission line, in order to establish power transactions between both countries, requires the involvement of many energy market players like: system operators, transmission operators, energy policy makers, generation companies, consumers and governmental entities. The “Instituto de Investigaciones Tecnológicas para Redes y Equipos Eléctricos” (IITREE) from La Plata National University, was responsible for performing power measurements, due to the fact that according to power system studies performed by the IITREE and the “Compañía Administradora del Mercado Mayorista Eléctrico S.A." (CAMMESA), a poorly damped electromechanical oscillation in the electrical power was expected.