Decision-making information from substation IEDs drives equipment life extension, modernization, and retrofitting

Much of the power system equipment in use today is nearing or has passed its predicted operating life, and we are pushing equipment to increasingly higher levels to meet demands. Injuries, failed equipment, unscheduled downtime, and loss of production are concerns that require knowledge of in-service power system apparatus. This is coupled with the competitiveness of the electrical energy market. The prevention of faults and defects in substation primary equipment is considered a major differentiating factor in the quality of power delivered by utilities. The reduction of faults and defects that cause interruptions in the supply of electrical energy significantly improves service performance rates. To achieve this objective, more efficient and intelligent maintenance practices are required and material, human, and financial resources must be invested correctly. The rules and requirements of the modern market no longer permit numerous corrective maintenance procedures or periodic maintenance practices. Recent cost-effective improvements in performance and power supply quality indexes have been demonstrated by utilities that have migrated from periodic and intensive corrective maintenance practices to predictive maintenance identified by substation equipment monitoring systems. The substation equipment monitoring system described in this paper meets the requirements of maintenance engineering teams by monitoring substation equipment, such as power transformers, circuit breakers, dc battery systems, and disconnect switches. Collection of this information is a convenient byproduct of the digitalization of communications messages among protection, control, and monitoring intelligent electronic devices (IEDs) in distribution substations for real-time automation and protection applications. Reuse of data within these IEDs for the purpose of equipment monitoring minimizes the need for new devices, such as special-purpose meters and sensors. Using protection, control, and m- nitoring IEDs as the source of information to understand the health and performance of substation apparatus makes the implementation of a monitoring system economical and technically attractive.