Integrated Substation Automation Enable New Strategies for Power

INTRODUCTION In view of the envisaged competitive electricity market era, utilities are examining the application of information technology (IT) as an alternative to support corporate business strategies that focus on improving service, power quality and reducing cost of operation and maintenance. Key issues for the improvement of the overall productivity are more and better information concerning the entire system behaviour, service condition of physical assets, e.g. circuit breakers and power transformers, as well as cost efficient operation and maintenance management. In the increasingly competitive arena there is significant pressure on power providers for greater system reliability and improvement of customer satisfaction, while similar emphasis is placed on cost reduction. These cost reductions focus on reducing operating and maintenance (O&M) expenses, and minimizing investments in new plants and equipment. If plant investments are to be made only for that which is absolutely necessary and the existing system equipment must be pushed to greater limits in order to defer capital investments. Substation Automation (SA) in comparison with a remote terminal (RTU) concept means decentralisation of computer capacity, which shall be used e.g. for intelligent automatic power restoration procedures after faults and for powerful decentralised processing of service and environment condition related data. Utility executives, on the other hand, are increasingly examining automation solution alternatives to support corporate business strategies that focus on improving service reliability and reducing cost of operation and maintenance. In the past, utility engineers often struggled with the fact that too little data was available when they attempted to analyze problems within their power systems. They also did not have enough information to predict or ascertain the level of maintenance needed of when it would be required for the major equipment located within their substations. As new and higher levels of digital technologies have made its way into substations in terms of numerical protection devices and control systems, these same engineers are suffering from data overload. They have more data than can be processed and assimilated in the time available. Today the challenge is to automatically convert data to knowledge, which frees manpower to implement corrective or preventive maintenance. It is suggested that intelligent electronic devices (IED) shall be implemented for protection and control tasks in substations to substitute electro-mechanical or static devices. In a modern SA system theses IEDs provide an infrastructure to collect, to process and to transmit data and information, which are utilised for cost effective condition monitoring of circuit breakers, power transformers, instrument transformers etc. This idea is illustrated by an example for power transformer condition monitoring. The SA system provides a user-friendly overview for the actual transformer condition. This comprises condition-related parameters like: service current, temperatures, and quality of insulation oil, partial discharge measurements and loads. WORKING PLANTS HARDER The integration of the various SA systems in a high performance communication network allows system wide adaptive protection and real time automatic power restoration procedures Various aspects of the utilities needs have been revealed in the Cigré 99 London Symposium on the subject: “Working Plant and Systems harder”. Enhancing the management and performance of plant and power systems is being discussed widely at many international conferences. The overall conclusion perceived is that there are a lot of new technologies available, which will help planners and operators to find new solutions to maximise the use of the power systems and adapt to the fast changing environment.