Flexible input relay architecture for a converter to operate from disparate power sources

Telecommunication service providers are adding renewable power sources for powering evermore of their telecommunication sites, such as central offices and cell towers. Such options bring benefits in operating costs and increased reliability especially in remote sites. However, it also introduces a host of new, often disparate equipment to the network that the service providers must maintain and replace as years go by. A rectifier that is capable of accepting disparate power sources and has the intelligence to identify and operate with maximum efficiency under any given operating conditions is highly desirable. However, it is important that the protection circuitry shall handle all scenarios of these disparate sources and protect the power converter circuitry from hard failures and thermal events. The most expensive and bulky option would be provide a protective relay circuitry for every source type and its associated fault scenarios. This paper presents a protection relay architecture that optimizes cost & size while protecting from disparate source types. It only uses AC relays for their smaller size and effectively isolates solar or utility grid inputs from any internal faults or failures.