Medium Term Horizon

The planning process for electric operation gives rise to two basic products: Medium Term Electrical Operation Plan (PEL) and the Guidelines for Electrical Operation with Four-Monthly Horizon (QEL).

PEL presents the evaluations of electrical performance of the BIPS for the period between the months of January 2013 and April 2014, while the QEL details for each four months of the current year, the operative measures necessary to the operation to meet the standards and criteria established in the Grid Procedures, to reconcile electrical restrictions and compliance with load with energy policies. All aimed at the lowest cost in operation and maximum operational security of the BIPS.

PEL 2013/2014 studies have been mainly developed to evaluate the performance of regional interconnections, the need for thermal generation due to transmission constraints and compliance with electrical areas of the BIPS. From these evaluations, stand out the main results of studies of the adaptation proposals of the schedule of planned works to the needs of the BIPS, operative solutions - such as the deployment of Special Protection Systems (EPS) -, the change of the grid topology, plus operational strategies to be used in the operation of the BIPS in this horizon.
In PEL 2013/2014, studies have aimed at identifying the necessary actions to ensure greater reliability for cities that will participate in the Confederations Cup: Brasilia, Belo Horizonte, Rio de Janeiro, Salvador, Recife and Fortaleza. The diagnosis considered the current system and works likely to be completed by May 2013.

Several actions have been proposed, with emphasis on the need for thermal generation and implementation / review of Special Protection Systems, aiming to ensure additional security to the BIPS during the event of the Confederations Cup.

The four-month study (QEL) has the aim to support the development of the operating instructions used by ONS to fulfill its mandate of coordinating the operation of the BIPS. Furthermore, they also help assessing the performance of Special Protection Systems (SEP) in operation, indicating the need for revision or deactivation of existing and installation of new ones. They define the need for thermal generation by electrical constraints as well as the limits of transmission in regional interconnections and geoelectric areas.

Within four-monthly studies, there is the search for alternatives to meet Distrito Federal, considering the existing transmission system and its evolution until April 2013, when it is anticipated that the works that will allow the closing of the ring in 138 kV between substations Samambaia and Brasilia Sul. In this context, conjunctural alternatives have been presented to provide greater security and reliability to the system supply to the nation's capital.

Regarding the aspects related to operational electrical security, ONS has coordinated several actions together with the agents of transmission, generation and distribution in order to diagnose the main weaknesses of the BIPS and indicate the measures to be made in order to revitalize the existing facilities, adapting them to the security standards set in the Grid Procedures.

The Plan for Facilities Modernization (PMI) indicates the works of revitalization and improvements needed to maintain adequate service provision by the transmission utilities, and also lists the interventions improvements and reinforcements that must be implemented by generators and distributors.

PMI developed in 2012 includes the period between 2012 and 2015 and recommended the implementation of 264 renovations, with a few small facilities, with 247 for transmission companies, 16 for distribution companies and one for a generation company.

Short Term Horizon

Throughout 2012, ONS developed studies and implemented contingency measures that allowed operating the grid in accordance with the criteria of continuity, reliability and quality of supply set out in the Grid Procedures, as outlined below.

Among the studies carried out, it is worth mentioning:

• The analysis of about 40,000 interventions in the Brazilian Interconnected Power System - BIPS, in which it was guaranteed systemic security during the period of the mentioned interventions.
• The deployment and monitoring of the performance of autoreclosing schemes of BIPS transmission lines to ensure continuity of service with increased reliability.
• Optimization of generators control systems to ensure adequate damping of oscillations and prevent loss of synchronization in the occurrence of disturbances.
• The definition of the Special Protection Systems in order to ensure operational security of the BIPS, even in the occurrence of multiple contingencies.
• The definition of new fluent restoration corridors of the BIPS, as well as updating the existing ones, in order to accelerate the normalization of supply after disturbances.

Among the results, we highlight the beginning of the services needed at 138 kV Samambaia substation , belonging to Furnas, to power the new 138 kV transmission line Riacho Fundo - Samambaia, belonging to CEB, which contributed to the improvement of loads supply in Distrito Federal.

At the end of 2012, new export limits from Southeast and Midwest to the North and Northeast were set, aiming at preventing that the North / Northeast system frequency ranges less than 57.1 Hz, in the event of loss of interconnections North / South and Southeast / Northeast.

Another highlight was the entry into operation of Araraquara 2 substation in 2012, part of the receiving system of the power to be transmitted by the dipoles 1 and 2 Porto Velho - Araraquara 2, allowing the flow of the plants of the Madeira Complex to Southeast .

It should be noted that the entry into operation of substation Araraquara 2, consisting of three 500/440 kV - 3x1250 MVA transformers, two circuits of 500 kV TL Araraquara 2 - Araraquara and two circuits of 440 kV TL Araraquara 2 - Araraquara, allowed the coupling of 500 kV and 440 kV grids in São Paulo, providing the BIPS important additional resource for balancing reactive power in 500 kV, 440 kV and 345 kV trunks. This provided relief in the generation of reactive power by synchronous compensators located in substations Ibiúna, Tijuco Preto, Embu Guaçu and Santo Ângelo.

It is noteworthy that these new developments have contributed to the mitigation of problems related to the control voltage in 440 kV São Paulo substations, especially in situations of high exchanges to the Southeast.