N221-064 TITLE: Medium Voltage Direct Current Disconnect Switches
OUSD (R&E) MODERNIZATION PRIORITY: General Warfighting Requirements (GWR)
TECHNOLOGY AREA(S): Ground / Sea Vehicles
OBJECTIVE: Develop a family of disconnect switches and associated switchgear enclosures for 12 kV Medium Voltage Direct Current (MVDC) electrical distribution systems for naval combatant applications.
DESCRIPTION: Integrated Power and Energy System (IPES) offers the potential to provide revolutionary warfighting capability at an affordable cost. IPES utilizes integrated energy storage and power along with advanced controls to provide a distribution bus suitable for servicing highly dynamic mission loads and propulsion demands while keeping the lights on. Additionally, such a system can enhance survivability, reliability, and flexibility while providing new capabilities, such as the ability to quietly maneuver solely on energy storage. IPES development is focused on a Medium Voltage Direct Current (MVDC) system evolved from the DDG 1000 1kVDC Integrated-Fight-Through-Power system, combined with shared and distributed energy storage as well as advanced controls with active state anticipation data linkage between machinery and combat systems. As threat capabilities improve over the coming decades, the Navy anticipates a heavy reliance on high power, highly dynamic, pulsed weapons and sensors. Because the need for generator synchronism is eliminated, MVDC is anticipated to be able to support these systems at lower cost, lower weight, and lower space requirements. Details on IPES are provided in the Naval Power & Energy Systems (NPES) Technology Development Roadmap [Ref 1].
One of the key enablers of an MVDC IPES is a reliable means for MVDC equipment isolation to conduct maintenance and fault isolation on the MVDC bus. Disconnect switches, in conjunction with appropriate protection relays, offer the opportunity to fulfill these functions at a lower size, weight, and cost than MVDC circuit breakers. MVDC disconnect switches and associated switchgear are enablers for affordable naval power and energy systems to support multiple future high power, pulsed sensors, and weapons on future surface combatants. Commercial or military MVDC disconnect switches and associated switchgear are not currently manufactured by any company. More information on MVDC Fault Detection, Localization and Isolation can be found in Doerry and Amy [Ref 2].
The objective of this SBIR topic is to develop a family of MVDC two pole disconnect switches and associated switchgear for 12 kV MVDC distribution systems on naval ships with continuous current ratings ranging from 100 amps to 3,500 amps (threshold) and 4,000 amps (objective). The challenge will be to develop affordable, power dense disconnect switches suitable for naval surface ship applications that can be locally or remotely controlled and can be opened or closed within 50 milliseconds (ms) (threshold) or 10 ms (objective). The disconnect switches shall be capable of interrupting at least 2% (threshold) or 100% (objective) of the rated current. The disconnect switches shall have a design life of 30 years (threshold) or 50 years (objective) and be capable of up to 10,000 switch operations (threshold) or 20,000 switch operations (objective). The disconnect switches shall be compatible with 12 kV power as detailed in the Preliminary Interface Standard, Medium Voltage Electric Power, Direct Current [Ref 3]. The steady-state efficiency of the disconnect switch shall be greater than 99.98% (threshold) or 99.99% (objective).
The switchgear enclosure for the disconnect switches should be modular to enable custom configurations of disconnect switches based on the sources and loads within a zone. The switchgear should minimize weight and maximize power density. For a single 2,000 amp two pole disconnect switch, the associated switchgear module shall have a power density greater than 20 MW/m3 (threshold) or 50 MW/m3 (objective) and shall weigh (including the disconnect switch) no more than 1,200 kg (threshold) or 200 kg (objective). The switchgear should be deck mounted (threshold) or bulkhead mounted (objective) while still meeting Grade A shock requirements. The switchgear should be air cooled. The switchgear should be capable of being integrated with MVDC cables or with MVDC insulated bus pipe. All repair parts should fit through standard shipboard hatches. The contractor shall demonstrate through testing in their own facilities the ability of the switchgear and disconnect switches to achieve the design ratings.
These MVDC disconnect switches are anticipated to have commercial applications as MVDC systems are increasingly employed in micro grids, offshore wind, cruise ships, and solar power installations.
PHASE I: Develop initial design concepts for the disconnect switches and associated switchgear for the complete family of disconnect switches. Establish the standard disconnect ratings comprising the family based on minimizing cost and size of switchgear for shipboard applications. Conduct electrical, mechanical, and thermal dynamic simulations to demonstrate the feasibility of the design. Assess risks associated with the design and develop mitigation plans. Risks not requiring physical testing of the prototype shall be addressed in the Phase I option.
In the Phase I option, if exercised, develop test plans that include risk mitigation requiring physical testing of the prototype for Phase II. Develop interface descriptions and performance data for the disconnect switches and associated switchgear necessary for successful integration into a shipboard power system.
PHASE II: Develop, test, and deliver to the Navy prototype switchgear and installed prototype disconnect switches in accordance with the draft specifications developed in Phase I or an update to the draft specification. The ratings of the prototype disconnect switches and the configuration of the prototype switchgear shall be chosen to maximize learning and risk mitigation. Demonstrate through testing in their own facilities the ability of the switchgear and disconnect switches to achieve the design ratings. Validate or update simulations from Phase I based on test results. Deliver to the Navy an update to the interface descriptions and performance data and develop design guidance for configuring and integrating the disconnect switches and associated switchgear into an MVDC power system design.
PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology to Navy use. The MVDC disconnect switch and associated switchgear are planned to be incorporated into a future surface combatant to support high power and pulsed power weapon systems. Commercial applications may include cruise ships, offshore platforms, wind farms, and solar farms. Produce and test production representative disconnect switches and associated switchgear enclosures in accordance with the Phase III SOW. These production representative disconnect switches and associated switchgear shall be delivered to the Navy for integration into a test system to evaluate the disconnects and switchgear for application in a future surface combatant. Deliver to the Navy an update to the design guidance from Phase II, an update to the simulation models (as required), a maintenance manual, and user training material.
KEYWORDS: Medium Voltage Direct Current; MVDC Disconnect switch; Switchgear; MVDC Equipment Isolation; MVDC Distribution System; MVDC Bus; MVDC Fault Isolation
** TOPIC NOTICE **
The Navy Topic above is an "unofficial" copy from the overall DoD 22.1 SBIR BAA. Please see the official DoD Topic website at rt.cto.mil/rtl-small-business-resources/sbir-sttr/ for any updates.
The DoD issued its 22.1 SBIR BAA pre-release on December 1, 2021, which opens to receive proposals on January 12, 2022, and closes February 10, 2022 (12:00pm est).
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