Protecting A Low Voltage Direct Current System Using Solid-State Switching Devices for DC Grid Applications

Abstract

LVDC transmission has fewer distributional losses than AC distribution, integrating renewable sources, greatly increasing the mix of clean energy sources in the standard grid in the next decade and this has become a trend that is likely to continue.  As an additional benefit, DC electrical power is oftentimes seen as beneficial to applications that use cleanly generated, renewable power. Considering DC power system design, and focusing on fault protection and the systems DC circuit breaker, are system priorities. Only solid-state circuit breakers (SSCB) should be considered to obtain advanced system topography. A new type of solid state circuit breaker is being developed as a new power device for LVDC power networks to replace the EMCB. The only suitable candidate for this task is the insulated gate bipolar transistor (IGBT). Development of DC grid protection allows for the development and improvement of new power electronic devices, focusing in on the application for medium to low voltage DC grids, a rapidly acting switching function as well as fault current limiting features. To avoid nuisance tripping, fault current limiting function can be satisfactorily accomplished by extending the elapsed time using the same control circuit. This paper introduces a novel circuit breaker model for LVDC, which utilizes a coupled inductor circuit breaker, and a mathematical model of IGBT has been developed.