Real-time Monitoring and Assessment of Circuit Breaker Operations for Diagnostics and Control Applications

Circuit breakers (CBs) are very important elements in the power system. They are used to switch other equipment in and out of service. Circuit breakers need to be reliable since their incorrect operation can cause major issues with power system protection and control. Today’s practice in monitoring circuit breaker operation and status in real time is reduced to the use of Remote Terminal Units (RTUs) of Supervisory Control and Data Acquisition (SCADA) system to assess CB status. More detailed information about the control circuit performance may be obtained by CB test equipment typically used for maintenance diagnostics [1]. This paper addresses two important issues: a) how improved CB monitoring may be implemented in real-time, and b) what would be the benefits of such an implementation. The results reported in this paper are coming from two research projects, conducted using funding from CenterPoint Energy and DOE-CERTS aimed at development of software for automated analysis of CB data and the other covering development of the CB data acquisition unit respectively. The paper is devoted to description of a prototype implementation of a real-time CB monitoring system. The system consists of a new CB monitoring data acquisition IED that is located at circuit breaker and captures detailed information about its operation in real-time. The CB files are transferred to the concentrator PC where the application software performs automated analysis and makes an assessment about the operational status of the breaker. The software is based on signal processing and expert system processing. Application example using actual field data is discussed. The paper ends with some conclusions, acknowledgments and a list of references.