A circuit breaker is an important equipment to power electric networks. Its importance is due to the protection role it is playing. Hence, it is imperative to assure its proper operation. This is only possible by applying suitable maintenance. The main purpose is to help us understand, accurately, the real condition of the breaker being tested thus helping targeting the corrective actions. This targeting helps minimize maintenance spending and increase network reliability, hence leading to efficient network management. A power circuit breaker is equipment intended to switch on and off electric currents on power transmission and distribution networks for routine operations and protection of other equipment. Electric transmission system breakups and equipment destruction can occur if a circuit breaker fails to operate because of a lack of preventive maintenance.
Its name, circuit breaker, indicates clearly its role. It breaks electric circuits. To achieve this purpose, it separates mechanically two points in the circuit to a
certain distance large enough to break the flow of electric currents. Circuit breakers come in a great variety and use different technologies:
Despite the big difference all types share common principals, they all have to provide two main functionalities highly related:
• Electrical functionality (Interrupter).
• Mechanical functionality (Mechanism).
The need for maintenance of circuit breakers is often not obvious, as circuit breakers may remain idle, either open or closed, for long periods of time. The need to
predict the proper function of circuit breakers grew over the years as transmission networks expanded and carried increasing energy to longer distances.
The technology advance over the years brought low maintenance breakers but it did not bring more reassurance to network management as to the reliability
of operation. The circuit breaker is, in fact, a black box. The only way to be sure of its condition is to open it for physical inspection. Unfortunately, this way is costly and must be reduced to minimum to prevent unnecessarily maintenance.