Sistema para seleção automática de grupos de ajustes em relés de proteção

Abstract

The modern systems of measurement, protection, command, control and supervision (MPCCS) have contributed in a meaningful way to increase the security and reliability of the power systems. The most important part of this multifunctional system is the protection system, which has as the main goal to maintain the power system integrity when it is under a disturbance, assuring the people‟s safety as well as the continuation of the services to the part of the system not involved in the disturbance. For this, the protection system must fulfill some basic requirements such as: proper selectivity and coordination, prompt response, sensitivity to protect the largest zone as possible and reliability. In a system protection, one component takes on a prominent position, given its functional importance: the digital protection relay. It is in this device where the necessary adjustments are configured for proper operation of the protection scheme of a given electrical power system. The digital relays are devices that have several protection functions, with multiple levels of settings, measurements, oscillography, supervision, control and communication. Besides all these features, the digital relays have multiple groups of settings that can be previously configured and switched among them, according to operational needs. The changing of setting group in a relay is a very important resource at a protection system, extensively used by protection sectors of companies in the power sector, allowing the optimization of the protection system setting, making it compatible to a new topology taken on by the system after a fault or an intentional removal of some system component. Nowadays this procedure is performed manually, making it vulnerable to human errors that might occur as a consequence of an outage, with serious effect in the system performance indices. In this sense this work presents a system, based on Colored Petri Nets, able to automatically change the setting groups of a protection system when the power network topology changes. This system monitors in real time the status of the circuit breakers in order to take the decision whether a meaningful change in the network topology has taken place. If so, a command is automatically sent to the relays to change the active group setting so as to maintain a suitable coordination of the protection system.