Medium Term Horizon

The process of electric operation planning, in the context of the annual cycle of the operation planning, resulted in two basic products. The Medium Term Electrical Operation Planning, PEL 2012/2013, presents the evaluations of the electrical performance of the BIPS for the period between the months of January 2012 and April 2013. The second product is composed of the Quarterly Electrical Studies (QEL), which detail - every quarter of the current year - the operational measures so that the operation meets the standards and criteria established in the Grid Procedures, in order to reconcile the electrical constraints and services to the load with energy policies, aiming at the lowest cost of operation and maximum operational security of the BIPS.

 Load forecasts informed by agents and consolidated by ONS, as well as the program of works presented in the 2011-2013 Basic Grid Expansions and Reinforcements Plan (PAR) and in the 2011-2013 Basic Grid Works Consolidation, which considers the dates updated by the Power Sector Monitoring Department (DMSE/MME) for the schedules of transmission and generation works authorized by ANEEL are basic information for the evaluations carried out by ONS.

The studies of PEL 2012/2013 were developed primarily to assess the performance of regional interconnections, the need for thermal generation due to transmission constraints and the service to electric areas of the BIPS.

From these evaluations, stand out as main results of the studies of PEL 2012/2013: proposals to adapt the schedule of the planned works to the needs of the BIPS; operational solutions, such as the deployment of Special Protection Systems (EPS) and the change of the grid topology, as well as operational strategies that will be used in the power operation of the BIPS in this horizon.

In 2011, in parallel with the studies of PEL and QEL, ONS conducted analyzes with particular focus on supply to some states through specific working groups, whose results were discussed in section 2.1.2.

The highlight of this annual cycle of power operation planning was the integration of the studies elaboration processes of PAR and PEL, which first occurred in 2011. This process integration has brought a new approach to ONS studies horizons, through which it was possible to rationalize the efforts of the technical teams and get a better adjustment of the time horizons for deployment of the resulting recommendations from each study. In addition, to the agents there was an improvement of their interaction with ONS, since the task of providing data for the studies of PAR and PEL is now performed only once. The integration of these processes resulted in elimination of shadow areas, more concise products and more robust results and recommendations.

In addition to subsidizing short-term electrical studies with monthly horizon in the scope of Operation Scheduling, quarterly studies evaluate the performance of Special Protection Systems in operation, indicating the need for revision or deactivation of the existing ones and the installation of new SEPs; define need for thermal generation for electrical constraints as well as transmission limits in the regional interconnections and to geoelectric areas. QEL also subsidizes the development of the operating instructions used by ONS to fulfill its duties of coordinating the operation of the BIPS in real time.

The results of 2011 Power Operation Annual Planning also supported ONS participation on working groups and task forces dealing with the power supply to the host cities during the World Cup 2014, which results were discussed in section 2.1.4.

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

Through the Normative Resolution No. 443 of 07.26.2011, ANEEL established a new systematic to be adopted by ONS and the agents for the development of the Facilities Modernization Plan (PMI), which shall be submitted annually to the regulatory agency. This Plan indicates the revitalization works and improvements necessary to maintain adequate service provision for the transmission utilities. In addition to the set of works of improvements in facilities under the responsibility of the transmission utilities, PMI also lists the improvements and reinforcement interventions to be implemented by distribution utilities or permit holders, and utilities or authorized generators. In this new form of work, the reinforcement of the transmission companies were consolidated in the Expansions and Reinforcements Plan (PAR).

PMI developed in 2011 covers the period between 2011 and 2014 and recommends the deployment of 232 revitalizations, with some smaller installations, being 202 for the transmission companies, 25 for the distribution companies and five for generation companies.

Short Term Horizon

Throughout 2011, ONS developed studies and implemented conjunctural measures that allowed operating the grid in compliance with the criteria of continuity, reliability and quality of supply set out in the Grid Procedures, as outlined below.

The entry into operation of 525 kV525 kV Foz do Iguaçu-Cascavel Oeste transmission line in December increased the power transfer capacity between Southeast and South subsystems, and allowed to expand the use of Itaipu power plant generation in  60 Hz to attend the demand of the BIPS.

Among the studies carried out, following stand out:

• Implementation and performance monitoring of automatic restart schemes of the BIPS’ transmission lines in order to ensure the continuity of services with increased reliability.
• Optimization of generators control systems to ensure adequate damping of electromechanical oscillations and to avoid loss of synchronization in the event of disturbances.
• Calibration of Special Protection Systems, to ensure operational security of the BIPS, even in the event of multiple contingencies.
• Definition of new corridors for system fluent restoration and upgrading of existing ones in order to accelerate the normalization of supply after disturbances.

Among the results obtained stands out the feasibility of serving priority loads in the city center of Sao Paulo in the process of restoration of the system, depending on the revision of the fluent corridor of Luiz Carlos Barreto hydroelectric power plant.

The operative conjunctural measures adopted were intended to prevent unacceptable conditions in normal operation as well as reduce the impacts of the occurrence of emergencies.

For example, the opening of a 230 kV busbar at Aimorés substation allowed reducing overloads on the equipment of the transmission grid at 138 kV of Escelsa and minimizing the spillage at Aimorés hydroelectric plant, avoiding the flooding of areas downstream, which would cause risk to the local population.

Another example of these measures occurred in the state of Goiás. The load increase due to high temperatures simultaneously to the unavailability of one of the transformers of Bandeirantes substation – which serves most of the state load – resulted in the transformation overload, being necessary high cost thermal dispatch for its control. In this situation, ONS decided to open the 230 kV of Cachoeira Dourada substation, directing much of Cachoeira Dourad generation to serve Goiás loads, easing the transformation of Bandeirantes and minimizing or eliminating thermal dispatch.