Strategic Installations

The concept of strategic installations covers power plants, substations and transmission trunks which, if turned off by electric problems or destroyed / damaged due to other reasons, the interruption of its services may lead to the occurrence of loss of large energyblocks and / or load, causing a major impact on society.

From the awareness of the strategic installations, ONS, since 2012, with the participation of the Agents involved, has undertaken the following actions:

• Identification / update ofthe set of assisted substations.
• Improving of information involving: environmental weather conditions (rain and direction of windstorms, lightning, air temperature, atmospheric pressure) and bushfires, available at Operation Centers, to prepare the BIPS for any multiple contingencies.
• Interaction with the expansion planning area for defining reinforcements that minimize the consequences of certain multiple losses.
• Implementation of new Special Protection Systems (SEP)
• Improvement of new SEPs design to minimize accidental or incorrect actuations.
• Adoption of more conservative criteria when maintenance services are carried out in those installations.
• Adoption of special criteria for testing of black-start generating units devices.

 

In order to make the BIPs more resilient, a working group composed by representatives of MME, ANEEL, EPE, ONS and Cepel was created,under technical coordination of ONS. The studies had the participation of agents owninginstallations. The goal was to identify the substations that needed arrangement complementarities or other measures to improve their intrinsic security.

The prevention from sequences of events can cause major disturbancesinvolving substations engineering,aiming to:

• Minimize the risk of human error in the facilities’ operation and maintenance;
• Provide protection, automation, control, monitoring and supervision in accordance with the Grid Procedures, which may be exceeded whenever the peculiarities of the installations require.
• The preparation of the work consisted of verifying full compliance with the requirements set in Sub-module 2.3 of the Procedures regarding busbar arrangement:
• In substations with double bus arrangement with single circuit breaker, the deployment of an adaptive bus protection was proposed, together with the circuit breaker failure protection;
• Assessment of the possibility of reducing contingencies consequences, which may lead to major disturbances, such as of failure in the circuit breaker opening;
• Measures to minimize risks through improvements regarding busbar arrangements;
• Possible use of hybrid technology, with compact modules for equipment baysand construction of new sectors using GIS technology (Gas Insulated Switchgear).

 

As a result of the analysis, it was possible to identify the substations that needed arrangement complementarities or other measures considered necessary to improve substations’ intrinsic security, and along with that the Brazilian Interconnected Power System’s performance as a whole. 439 Main Gridinstallations 13 substations, which are part of ONS Operation Network were analyzed.

Figure 1 shows the general diagnosisin compliance withthe Grid Procedures after the implementation of all the recommended improvements.

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Figure1 – Compliance with Grid Procedures– General Diagnosis

 

Performance Evaluation of Special Protection Systems

The criteria and procedures for the implementation of functional tests on the Special Protection Systems (SEPs) installed on the BIPS were set in 2012 in order to ensure proper performance. Between 2012 and 2014, tests were performed on 81 SEPs installed in several areas of the system. In 2015, continuing the process, 11 additionaltests were carried out. For each test, a report was elaborated, containing a brief description of the system, its purpose, the tests carried out, that abnormalities that could be encountered and the measures taken. Besides, in order to consolidating all tests performed in the previous year, a Technical Note was published by ONS in April / 2015.