**7. Conclusion**

optimized procedures for reconnecting. The suggestions are done in an interactive way through descriptions, visualization of the flowchart of the reconnecting maps and other re‐

b) When the mode "Training" is selected, the Paraconsistent Expert System - PESPAL2v will simulate the failure and step by step will present details about the procedures of the recon‐ necting flowchart. In order to begin the process the user has to inform the application the

When this information is input, the application shows on the reserved space at the left of the screen the unifilar representation of the selected substation. The next step is the user's action which selects the breakers which will be simulated as "off" in order to configurate a type of

When the simulation process is started the application, based on the breakers selected as "off" by the user, detects the type of alarm (CRs) which represents the disconnections and performs a search on the substation's database for the date that such failure occurred.

When the date of the occurrence is detected the application activates the networks of para‐ consistent analysis obtaining the evidence degrees of overload risk and other specific infor‐ mation together with the first suggestions from the flowchart of the reconnecting map.

The interactive process is similar to the one presented in the "Analysis" mode: the sugges‐ tions and actions already determined by the flowchart will be step by step presented until the end of the optimized reconnecting. Doing so, the training is totally performed from real

Figure 17 shows a screen of an operating substation in its unifilar diagram with all available values obtained by the paraconsistent analysis. A menu, where restoring sequences of the

data of failure occurrences represented by values stored in the database.

**Figure 17.** Analysis screen – Unifilar diagram and menu with information generated by PESPAL2v.

electric power system after a contingency, is shown to the user.

striction graphs.

56 Advances in Expert Systems

failure occurrence.

name of the substation he or she wants to simulate.

In this work it was shown that the paraconsistent logics has a great capability of application in technological processes with the aim to solve complex problems. The Paraconsistent Ex‐ pert System - PESPAL2v was designed with an analyzing block of contingency which is capa‐ ble of computing the risk degrees of outage by overloading of the electric power system. Moreover, given such occurrence, it is also capable of analyzing the conditions and of offer‐ ing a list of sequences of optimized restoring for the operation.

Currently the expert system built with the PAL2v is being used to assist operation and train‐ ing of operators at the operational substations of the electric power system of the AES-Ele‐ tropaulo – electric utility in Brazil. In the practice the paraconsistent expert system PESPAL2v has shown to be an efficient tool, with which the user understands and accepts the reason‐ ing methods used in the problem solving, since paraconsistent logics are more intuitive and has algorithms with simple structure. Generally speaking, it reached the following goals:


Together to the above three main features, we can add three more:


In operation, the PESPAL2v has shown to be computational software where the modulation parameters are easy to adjust and the analyzing block of contingencies is adapted to provide resulting information in a satisfactory way. It was tested under several conditions using real values which were stored into a database for 12 months.

The sub-transmission system which was tested was composed of 12 substations where it was possible to modify and test several topological configurations. Under all tested condi‐ tions, PESPAL2v showed good results and responded well to various situations in comparison to previous situations which were also stored into database.

The prototype application build in this first phase leave the necessary conditions fulfilled, so that the analysis process can be automatically started for the online implementation, topic which is for future projects. In this case, the alarms activated due to failures at the substa‐ tions whose data were stored in the database, will start the application so that the analysis phases of the process are started in real-time. Under these conditions PESPAL2v will with no doubt a very useful tool to the operation of the electric power system.

With this work it was shown that an expert system can be built with the algorithms of the paraconsistent logics and is capable of performing its fundamental task of analyzing contra‐ dicting information. Moreover, it is also capable to clearly show the user the reasoning meth‐ ods it is using, so that the user can interact with the system with high confidence degree.

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