A new approach of coordinated secondary voltage control applied in transmission and sub-transmission level

In this paper, a coordinated secondary voltage control (CSVC) applied to transmission and sub-transmission levels, in the context of deregulated power industry, is proposed. Using the principle of the CSVC, the system was divided into voltage control areas and some pilot nodes for each one were chosen to have voltages monitoring in order to describe the voltage behaviour inside the area. The automatic voltage regulators of LTC and switching of compensation devices (capacitors) provide the primary voltage control in the substation level (local control). The CSVC is carried out in two pilot node using information of the system (transmission and subtransmission margins) and local area (distribution system). Preliminary results the benefits of application of CSVC are illustrated through a real system of the electric power utility in South of Brazil. An area with a two pilot node was modeled to analyze the performance of the proposed CSVC. A steady-state approach was first used to determine the structure of the adequate control sequence to minimize system losses and reactive power interchanges and provide voltage stability and security.