High voltage circuit breakers signals in substation automation

Circuit breakers are composed of one or several sealed interrupting chambers that contain a dielectric gas (primarily SF6 gas), an insulating structure predominantly based on porcelain insulators, a set of components designed to supply the mechanical power necessary for quickly closing and opening the primary contacts, and a series of devices required for handling control commands and sensing relevant parameters and conditions.

Owing to the rigorous service that the circuit breaker is dedicated to, strict monitoring and signaling are essential. This is to ensure that the equipment can respond appropriately when a switching operation is commanded by protective relays or a bay controller. This situation gives rise to the necessity of proper management in SAS projects. There are a number of input signals related to the indication of the circuit breaker's position and the monitoring of various supporting media conditions. Additionally, there are output signals consisting of opening/closing command orders, as exemplified in the table below.