Brazilian Experience Regarding Interactions between Series Capacitors and SVCs - Main Challenges of Tucurui-Macapa-Manaus Interconnection Project

摘要

The power supply for both Amazonas and Amapa States, located in Amazon region, was done before 2012 through isolated systems. Techno-economic feasibility studies concluded that the best alternative for integrating these isolated systems was the erection of a 500 kV double circuit, on the same tower, connecting the Tucurui hydropower plant to the city of Manaus, forming the long 500 kV trunk Tucurui - Xingu - Jurupari - Oriximina - Silves - Lechuga with a total length of 1418 km. To supply the state of Amapa, a 230 kV double circuit, on the same tower, was recommended from Jurupari to Laranjal and further to Macapa, totaling 334 km. This project called Tucurui-Macapa-Manaus interconnection (TMMI) was divided for the purpose of auctioning in three lots involving 18 Fixed Series Capacitor Banks (FSC) with an average series compensation level of 70% and 4 SVCs. The basic characteristics of these SVCs and FSCs have been presented along with the interactions between them, explaining the process for which the subsynchronous oscillation (SSO) has an impact on the SVC voltage regulators. In this sense, the resonances of a typical series-shunt-compensated power system have been categorized. This article describes the issues related to all TMMI SVCs involved and the main findings regarding the possible instabilities caused by these SSOs as well as the solution adopted by each SVC manufacturer. Although the solutions are conceptually different, both of them fulfill the requirement for the SVCs to stop responding to sideband frequencies as far as possible in addition to being prepared for further action if a new contingency occurs subsequently. The strategy to prevent hunting among the SVCs has been described and its deployment explained. One can state that the solutions adopted have shown to be robust to provide both a flexible and safe operation for those SVCs running on TMMI. Finally the operational experience of TMMI with its SVCs has been shown to be in compliance with integration and RTS (real time simulation) studies. Some real disturbances have been recorded and they confirm the adequacy of SVCs to meet TMMI's system requirements. No power transfer limitation has been observed after the commissioning work and commercial operation of TMMI due to unforeseen aspects.