Health Monitoring for the Integrity of Electrical Pover Wiring and Power System Components

Control of electrical discharge is necessary to avoid degrading insulation in electrical wire cable. The need for such control is increased when the cable is used in aerospace systems where ambient pressures may be well below one atmosphere at flightaltitudes. The voltage required for onset of partial discharge at high frequencies can be significantly smaller than at low frequencies. For example, in wire at an altitude of 10 km, coronal onset voltage above 50 kHz was found to be 20% smaller than atfrequencies below 20 kHz, thus increasing the potential for partial discharge. Temperature and humidity also affect coronal onset voltage at high frequencies. In airborne and spacecraft electronic applications, insulated or even bare conductors may be usedfor high frequency signal transmission for radar or high power transmission applications. Continuous monitoring of such wiring is needed to predict incipient insulation failure.Therefore, Systems & Processes Engineering Corporation proposes to develop an Optical Health Monitoring System for wiring. The proposed system will permit real time, continuous monitoring of wiring at arbitrary pressures and excitation frequencies and willdetermine both magnitude and location of any discharge on the wire with spatial resolution of less than one foot. The transition of the technology to a commercial product is organic and central to the proposed program. The OHMS will permit monitoring the health of wiring systems' insulation in hazardous or otherwise inaccessible environments. This technology hasapplication to the commercial air industry, where it can be deployed in fuselages and wings to improve safe operation of hydraulic, fuel, and other critical control systems. Similar applications apply to ground vehicles and ships. The electric powerindustry can install the Optical Health Monitoring System (OHMS) along high voltage transmission lines to enable remote monitoring of voltage discharges.In addition, the system could easily be modified to also monitor temperature along the wires usingSPEC's Distributed Temperature Sensor (DTS) technology originally developed for NASA. Similar applications also exist for the commercial broadcast industry to monitor and protect critical communication lines.