Replace, refurbish, or retain? Evaluating aging electrical systems and equipment

Many electrical facilities were constructed or experienced major expansions in the 1950s and 1960s. We are now having to deal with electrical switchgear and systems that are 40 to 50 years old. Depending upon the environment and application of the equipment, they may be at or near the end of their useful lives. In order to make an objective evaluation of the equipment´s condition and develop a forward plan for operation, reconditioning, or replacement, a detailed application guide for condition assessment of their aged medium-voltage (MV) switchgear was developed and described in this article. Over the past 40 to 50 years, the equipment has not only aged, but the electrical systems have often expanded to meet the needs of future growth and expansion. This growth has sometimes followed a well-planned strategy based on up-front conceptual studies integrated into long range plans. On other occasions, this growth has been achieved by adding on to existing facilities in an often haphazard manner, or by duplicating existing facilities, equipment, and designs. For a number of reasons, the reliability of our electrical facilities and related losses due to power failures may not be meeting our management´s expectations. This article describes a process developed to model an electrical system and calculate system reliability and related financial risks based on the actual system components and process unit cost impacts.