Modernization of Existing Low and Medium Voltage Switchgear and Motor Control Centers

Reliability of the electric supply is largely influenced by the reliability of the major components of the power distribution system. Amongst these, reliability of medium and low voltage switchgear and motor control centers (MCCs) have a key influence on power system reliability. The switchgear and MCCs installed three or four decades ago do not necessarily present the same levels of reliability as modern state-of-the-art equipment. Many end users including utilities and large industrials have older switchgear with air-magnetic or first-generation vacuum switchgear technologies that do not provide the level of arc fault protection which has come to be expected from modern industry standards. As such, this aging equipment does not provide an equivalent level of safety during maintenance and operation when compared to newer equipment. The maintenance issues are also complicated by the lack of spare parts, supply chain interruptions, limited opportunities for maintenance, capital budgets, and lengthy outages associated with the replacement of the aged equipment. Retrofitting, retrofilling or other modifications of the switchgear and MCCs can be more practical, cost effective, and more of an expeditious approach over the replacement of the switchgear. Additionally, modifying the protection, control, and metering, and creating a comprehensive communication network to analyze the data from the new relays, meters and condition monitoring systems allows for further improvements in operation and maintenance as well as successful conversion from time-based to condition-based maintenance programs. This paper addresses the various methods of modernization of low and medium voltage switchgear and MCCs.