Joint time-frequency optimized reference for surface wave reflectometry-based insulation health assessment

In this paper, we present a time-frequency based reflectometry solution that focuses on the practical implementation of in-situ and non-destructive cable diagnostic tests. Towards this ideal health monitoring approach, we have explored the implementation of alternative monitoring techniques using surface wave injection for monitoring of cable insulation health toward nondestructive tests. Through use of surface wave propagation, a diagnostic signal can be injected in control, instrumentation, and power cable without removing installed samples under test. However, in practical implementation of surface wave tests through antenna, problems are presented in the form of dispersive media distorting the response of the frequency sweeping reference signal in either frequency or time-frequency domains. We present an optimal reference signal and time-frequency cross correlation diagnostic and prognostic algorithm to allow for implementation of joint time-frequency domain reflectometry (JTFDR) in minimal bandwidth to reduce attenuation in surface wave reflectometry.