Utilizing Spread Spectrum Time Domain Reflectometry (SSTDR) to Automatically Detect Ground Faults in Live Shipboard Control Systems Navy SBIR FY2011.2 Sol No.: Navy SBIR FY2011.2 Topic No.: N112-133 Topic Title: Utilizing Spread Spectrum Time Domain Reflectometry (SSTDR) to Automatically Detect Ground Faults in Live Shipboard Control Systems Proposal No.: N112-133-1189 Firm: LiveWire Test Labs, Inc. 575 East 4500 South, Suite B-125 Salt Lake City, Utah 84107 Contact: James Stephenson Phone: (801) 293-8300 Web Site: www.livewiretest.com Abstract: The use of Spread Spectrum Time Domain Reflectometry (SSTDR) that has already been proven in aerospace applications will be adapted and optimized for detection and location of wiring faults in shipboard systems. SSTDR is the only technology that allows MCS fault detection and isolation, on fully powered systems without taking the console offline or disconnecting any of the system components, thus accelerating the mitigation and repair process. SSTDR detects and locates a full range of impedance changes and is therefore suitable for detecting when the minimum isolation resistance of 250K ohms, and locating the fault within 3% of the cable length. In contrast to traditional TDR methods that inject disruptive signals and require decoupling, LiveWire's SSTDR technology injects a very low amplitude Pseudo Noise (PN) code, which is well below a typical noise floor (<1V). The Phase 1 effort will demonstrate the ability to detect and locate a ground fault at a single location. The Phase 2 effort will leverage a multiplexed solution leveraging LiveWire's ASIC to detect and locate simultaneous grounds, including signal returns and signal shields connected to the ship's hull. We envision an ASIC SSTDR device integrated and leveraged within a ship's health management system architecture. Benefits: The proposed system operates on live (powered) systems, thus enabling ground fault detection and location while a ship is operating under typical naval conditions at sea, with a completely non-invasive, non-intrusive approach. While the Phase 1 system will simply display the type and distance (location) of a ground fault relative to the SSTDR test signal injection point, or MCS Control System, future generations will overlay this information on a visual map of the entire ship's wiring and control system, making it easy for even newly trained technicians to quickly troubleshoot and resolve wiring problems. The Linux-based operating system and standard data file format will allow interoperability with partners to merge the ground fault location and historical information with visual maps to enable best-in-class troubleshooting. We estimate that the operational availability of a ship can be improved to greater than 95% via real-time detection of intermittent faults ranging from dead short conditions to broken wires or open circuits. In addition, the LiveWire SSTDR technology has already demonstrated the ability to detect very short duration faults (<3 milliseconds), thus providing a powerful foundation on which to develop an intermittent shipboard ground fault solution and associated information management infrastructure. Return