Digital Methods for the Detection of Incipient Fault Conditions in Spaceborne Power Systems

The early detection and correction of fault conditions in spaceborne power systems is critical. For permanent space: installations it is absolutely necessary that catastrophic failure of power deliver systems be avoided when possible. Research has shown that advanced digital relaying and computer diagnostic techniques can be used to detect "incipient" fault conditions and low grade faults prior to catastrophic failure. This paper describes the application of classical detection theory to the detection of high impedance faults. The intent is that these new algorithms and approaches be implemented in "intelligent" relaying systems with adaptive capabilities. The systems are suitable for implementation using programmable digital signal processors. The fault detection problem is formulated as a statistical hypothesis testing in the presence of deterministic signals with random parameters and additive noise. The resulting optimal fault detector is a power detector and can be realized using a digital notch filter and a sliding sum of the squared output of the notched filter. A count of the number of energy bursts at the harmonic frequencies during a time interval is used to distinguish between faults and routine events. The method proposed can be used to detect faults and incipient failure conditions that cannot be detected by conventional protection methods used for spaceborne systems.