Medium Voltage Direct Current Protection Relays and Associated Sensors

The Navy requires a reliable high speed fault protection system for Medium Voltage Direct Current (MVDC) distribution networks to support advanced shipboard power systems. These MVDC systems are an evolution of the DDG 1000 1kV DC Integrated-Fight-Through-Power (IFTP) systems combined with advanced controls, shared/distributed energy storage, and data linkages. This allows for the power distribution bus to service highly dynamic mission loads and propulsion demands at a high reliability. The utility of the MVDC systems is further enhanced by additional use cases including quiet maneuvers on energy storage. The DDG(X), FFG-62, DDG-1000, CVN-78 (and any other ship with MVDC elements) will stand to benefit greatly from the maturation of MVDC technology through improved affordability and power density compared to legacy power systems.The successful realization of this technology hinges on the development of a reliable and affordable MVDC fault protection system. In a complex and distributed power architecture such as that of the DDG(X) and beyond, there is significant need for such a system to be capable of localizing and isolating the faults rapidly (to prevent the activation of overcurrent protection in Solid State Circuit Breakers (SSCBs)) without coordination with other parts of the system. The development of such a system is complex and requires an extensive life span (40-50 years), high reliability (>99% accuracy and uptime), and have limited false positives (30,000-300,000 hours between false positives).The purpose of this project is to develop a fault protection relay and sensor architecture to detect the presence of a fault, determine if a fault is within the protection zone, and initiate isolation commands within 8µS (1µS objective). This system will be required to interface with breakerless, breakered, and disconnect switch-type interfaces, requiring a flexible output and integration architecture to support current and future load integration. Ultimately, this design will be used for 1kV, 6kV, and 12kVMVDC systems for both directional and differential configurations.To accomplish this, EMA will develop and implement a flexible architecture to accurately sense, locate, and isolate faults within a zone architecture that can support both directional and differential architectures. Such a system, if successfully realized, has significant commercialization potential for other large ship architectures such as ferries, cruise ships, and similar.EMA will investigate the feasibility of several sensor paradigms and identify critical functional evaluations needed to down-select the most appropriate protection relay/sensor combination during the Phase I program. FPGA/comparator circuit combinations and mechanical directional/differential relays with logic circuitry are of interest here.