Decision model for End of Life management of switchgears

Due to a wave of investment in the 1960´s-70´s, a large amount of switchgear in W-Europe is now 30-45 years old. The number of ageing phenomena is increasing, and indicates that for certain types the end of service-life is showing up. Theoretically then, the switchgear should be replaced. In practice, however, service-life extension can be an option to reduce the required investment cost. Minimum long term cost of ownership should be the drive for the final decision. Based on case studies, a financial model has been developed that compares future costs for use-up, retrofit, re-conditioning, and full replacement. The model performs a financial analysis of the different scenarios, and provides the net present value of additional investments versus the minimum investment. A variety of factors representing financial value, are observed, such as power availability, safety, knowledge-management, resource allocation and risk on economical catastrophes. The data is derived from asset management strategies, field experiences, literature, historical manufacturer data, workshop experiences and case studies. The financial indicators of this method can validate the technical recommendations, and provide the required input to make a rational replacement decision for circuit breakers and switchgear.